mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-06 02:24:14 +08:00
14d071134c
This reverts commit cd544fd1dc
.
As discussed in [1] this commit was a no-op because the mapping type was
checked in vma_to_resize before move_vma is ever called. This meant that
vm_ops->mremap() would never be called on such mappings. Furthermore,
we've since expanded support of MREMAP_DONTUNMAP to non-anonymous
mappings, and these special mappings are still protected by the existing
check of !VM_DONTEXPAND and !VM_PFNMAP which will result in a -EINVAL.
1. https://lkml.org/lkml/2020/12/28/2340
Link: https://lkml.kernel.org/r/20210323182520.2712101-2-bgeffon@google.com
Signed-off-by: Brian Geffon <bgeffon@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Alejandro Colomar <alx.manpages@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Michael S . Tsirkin" <mst@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sonny Rao <sonnyrao@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2274 lines
56 KiB
C
2274 lines
56 KiB
C
/*
|
|
* An async IO implementation for Linux
|
|
* Written by Benjamin LaHaise <bcrl@kvack.org>
|
|
*
|
|
* Implements an efficient asynchronous io interface.
|
|
*
|
|
* Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.
|
|
* Copyright 2018 Christoph Hellwig.
|
|
*
|
|
* See ../COPYING for licensing terms.
|
|
*/
|
|
#define pr_fmt(fmt) "%s: " fmt, __func__
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/time.h>
|
|
#include <linux/aio_abi.h>
|
|
#include <linux/export.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/refcount.h>
|
|
#include <linux/uio.h>
|
|
|
|
#include <linux/sched/signal.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/file.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/percpu.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/timer.h>
|
|
#include <linux/aio.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/workqueue.h>
|
|
#include <linux/security.h>
|
|
#include <linux/eventfd.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/compat.h>
|
|
#include <linux/migrate.h>
|
|
#include <linux/ramfs.h>
|
|
#include <linux/percpu-refcount.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/pseudo_fs.h>
|
|
|
|
#include <linux/uaccess.h>
|
|
#include <linux/nospec.h>
|
|
|
|
#include "internal.h"
|
|
|
|
#define KIOCB_KEY 0
|
|
|
|
#define AIO_RING_MAGIC 0xa10a10a1
|
|
#define AIO_RING_COMPAT_FEATURES 1
|
|
#define AIO_RING_INCOMPAT_FEATURES 0
|
|
struct aio_ring {
|
|
unsigned id; /* kernel internal index number */
|
|
unsigned nr; /* number of io_events */
|
|
unsigned head; /* Written to by userland or under ring_lock
|
|
* mutex by aio_read_events_ring(). */
|
|
unsigned tail;
|
|
|
|
unsigned magic;
|
|
unsigned compat_features;
|
|
unsigned incompat_features;
|
|
unsigned header_length; /* size of aio_ring */
|
|
|
|
|
|
struct io_event io_events[];
|
|
}; /* 128 bytes + ring size */
|
|
|
|
/*
|
|
* Plugging is meant to work with larger batches of IOs. If we don't
|
|
* have more than the below, then don't bother setting up a plug.
|
|
*/
|
|
#define AIO_PLUG_THRESHOLD 2
|
|
|
|
#define AIO_RING_PAGES 8
|
|
|
|
struct kioctx_table {
|
|
struct rcu_head rcu;
|
|
unsigned nr;
|
|
struct kioctx __rcu *table[];
|
|
};
|
|
|
|
struct kioctx_cpu {
|
|
unsigned reqs_available;
|
|
};
|
|
|
|
struct ctx_rq_wait {
|
|
struct completion comp;
|
|
atomic_t count;
|
|
};
|
|
|
|
struct kioctx {
|
|
struct percpu_ref users;
|
|
atomic_t dead;
|
|
|
|
struct percpu_ref reqs;
|
|
|
|
unsigned long user_id;
|
|
|
|
struct __percpu kioctx_cpu *cpu;
|
|
|
|
/*
|
|
* For percpu reqs_available, number of slots we move to/from global
|
|
* counter at a time:
|
|
*/
|
|
unsigned req_batch;
|
|
/*
|
|
* This is what userspace passed to io_setup(), it's not used for
|
|
* anything but counting against the global max_reqs quota.
|
|
*
|
|
* The real limit is nr_events - 1, which will be larger (see
|
|
* aio_setup_ring())
|
|
*/
|
|
unsigned max_reqs;
|
|
|
|
/* Size of ringbuffer, in units of struct io_event */
|
|
unsigned nr_events;
|
|
|
|
unsigned long mmap_base;
|
|
unsigned long mmap_size;
|
|
|
|
struct page **ring_pages;
|
|
long nr_pages;
|
|
|
|
struct rcu_work free_rwork; /* see free_ioctx() */
|
|
|
|
/*
|
|
* signals when all in-flight requests are done
|
|
*/
|
|
struct ctx_rq_wait *rq_wait;
|
|
|
|
struct {
|
|
/*
|
|
* This counts the number of available slots in the ringbuffer,
|
|
* so we avoid overflowing it: it's decremented (if positive)
|
|
* when allocating a kiocb and incremented when the resulting
|
|
* io_event is pulled off the ringbuffer.
|
|
*
|
|
* We batch accesses to it with a percpu version.
|
|
*/
|
|
atomic_t reqs_available;
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
struct {
|
|
spinlock_t ctx_lock;
|
|
struct list_head active_reqs; /* used for cancellation */
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
struct {
|
|
struct mutex ring_lock;
|
|
wait_queue_head_t wait;
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
struct {
|
|
unsigned tail;
|
|
unsigned completed_events;
|
|
spinlock_t completion_lock;
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
struct page *internal_pages[AIO_RING_PAGES];
|
|
struct file *aio_ring_file;
|
|
|
|
unsigned id;
|
|
};
|
|
|
|
/*
|
|
* First field must be the file pointer in all the
|
|
* iocb unions! See also 'struct kiocb' in <linux/fs.h>
|
|
*/
|
|
struct fsync_iocb {
|
|
struct file *file;
|
|
struct work_struct work;
|
|
bool datasync;
|
|
struct cred *creds;
|
|
};
|
|
|
|
struct poll_iocb {
|
|
struct file *file;
|
|
struct wait_queue_head *head;
|
|
__poll_t events;
|
|
bool done;
|
|
bool cancelled;
|
|
struct wait_queue_entry wait;
|
|
struct work_struct work;
|
|
};
|
|
|
|
/*
|
|
* NOTE! Each of the iocb union members has the file pointer
|
|
* as the first entry in their struct definition. So you can
|
|
* access the file pointer through any of the sub-structs,
|
|
* or directly as just 'ki_filp' in this struct.
|
|
*/
|
|
struct aio_kiocb {
|
|
union {
|
|
struct file *ki_filp;
|
|
struct kiocb rw;
|
|
struct fsync_iocb fsync;
|
|
struct poll_iocb poll;
|
|
};
|
|
|
|
struct kioctx *ki_ctx;
|
|
kiocb_cancel_fn *ki_cancel;
|
|
|
|
struct io_event ki_res;
|
|
|
|
struct list_head ki_list; /* the aio core uses this
|
|
* for cancellation */
|
|
refcount_t ki_refcnt;
|
|
|
|
/*
|
|
* If the aio_resfd field of the userspace iocb is not zero,
|
|
* this is the underlying eventfd context to deliver events to.
|
|
*/
|
|
struct eventfd_ctx *ki_eventfd;
|
|
};
|
|
|
|
/*------ sysctl variables----*/
|
|
static DEFINE_SPINLOCK(aio_nr_lock);
|
|
unsigned long aio_nr; /* current system wide number of aio requests */
|
|
unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
|
|
/*----end sysctl variables---*/
|
|
|
|
static struct kmem_cache *kiocb_cachep;
|
|
static struct kmem_cache *kioctx_cachep;
|
|
|
|
static struct vfsmount *aio_mnt;
|
|
|
|
static const struct file_operations aio_ring_fops;
|
|
static const struct address_space_operations aio_ctx_aops;
|
|
|
|
static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
|
|
{
|
|
struct file *file;
|
|
struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
|
|
if (IS_ERR(inode))
|
|
return ERR_CAST(inode);
|
|
|
|
inode->i_mapping->a_ops = &aio_ctx_aops;
|
|
inode->i_mapping->private_data = ctx;
|
|
inode->i_size = PAGE_SIZE * nr_pages;
|
|
|
|
file = alloc_file_pseudo(inode, aio_mnt, "[aio]",
|
|
O_RDWR, &aio_ring_fops);
|
|
if (IS_ERR(file))
|
|
iput(inode);
|
|
return file;
|
|
}
|
|
|
|
static int aio_init_fs_context(struct fs_context *fc)
|
|
{
|
|
if (!init_pseudo(fc, AIO_RING_MAGIC))
|
|
return -ENOMEM;
|
|
fc->s_iflags |= SB_I_NOEXEC;
|
|
return 0;
|
|
}
|
|
|
|
/* aio_setup
|
|
* Creates the slab caches used by the aio routines, panic on
|
|
* failure as this is done early during the boot sequence.
|
|
*/
|
|
static int __init aio_setup(void)
|
|
{
|
|
static struct file_system_type aio_fs = {
|
|
.name = "aio",
|
|
.init_fs_context = aio_init_fs_context,
|
|
.kill_sb = kill_anon_super,
|
|
};
|
|
aio_mnt = kern_mount(&aio_fs);
|
|
if (IS_ERR(aio_mnt))
|
|
panic("Failed to create aio fs mount.");
|
|
|
|
kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
|
|
kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
|
|
return 0;
|
|
}
|
|
__initcall(aio_setup);
|
|
|
|
static void put_aio_ring_file(struct kioctx *ctx)
|
|
{
|
|
struct file *aio_ring_file = ctx->aio_ring_file;
|
|
struct address_space *i_mapping;
|
|
|
|
if (aio_ring_file) {
|
|
truncate_setsize(file_inode(aio_ring_file), 0);
|
|
|
|
/* Prevent further access to the kioctx from migratepages */
|
|
i_mapping = aio_ring_file->f_mapping;
|
|
spin_lock(&i_mapping->private_lock);
|
|
i_mapping->private_data = NULL;
|
|
ctx->aio_ring_file = NULL;
|
|
spin_unlock(&i_mapping->private_lock);
|
|
|
|
fput(aio_ring_file);
|
|
}
|
|
}
|
|
|
|
static void aio_free_ring(struct kioctx *ctx)
|
|
{
|
|
int i;
|
|
|
|
/* Disconnect the kiotx from the ring file. This prevents future
|
|
* accesses to the kioctx from page migration.
|
|
*/
|
|
put_aio_ring_file(ctx);
|
|
|
|
for (i = 0; i < ctx->nr_pages; i++) {
|
|
struct page *page;
|
|
pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
|
|
page_count(ctx->ring_pages[i]));
|
|
page = ctx->ring_pages[i];
|
|
if (!page)
|
|
continue;
|
|
ctx->ring_pages[i] = NULL;
|
|
put_page(page);
|
|
}
|
|
|
|
if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
|
|
kfree(ctx->ring_pages);
|
|
ctx->ring_pages = NULL;
|
|
}
|
|
}
|
|
|
|
static int aio_ring_mremap(struct vm_area_struct *vma)
|
|
{
|
|
struct file *file = vma->vm_file;
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
struct kioctx_table *table;
|
|
int i, res = -EINVAL;
|
|
|
|
spin_lock(&mm->ioctx_lock);
|
|
rcu_read_lock();
|
|
table = rcu_dereference(mm->ioctx_table);
|
|
for (i = 0; i < table->nr; i++) {
|
|
struct kioctx *ctx;
|
|
|
|
ctx = rcu_dereference(table->table[i]);
|
|
if (ctx && ctx->aio_ring_file == file) {
|
|
if (!atomic_read(&ctx->dead)) {
|
|
ctx->user_id = ctx->mmap_base = vma->vm_start;
|
|
res = 0;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
spin_unlock(&mm->ioctx_lock);
|
|
return res;
|
|
}
|
|
|
|
static const struct vm_operations_struct aio_ring_vm_ops = {
|
|
.mremap = aio_ring_mremap,
|
|
#if IS_ENABLED(CONFIG_MMU)
|
|
.fault = filemap_fault,
|
|
.map_pages = filemap_map_pages,
|
|
.page_mkwrite = filemap_page_mkwrite,
|
|
#endif
|
|
};
|
|
|
|
static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
vma->vm_flags |= VM_DONTEXPAND;
|
|
vma->vm_ops = &aio_ring_vm_ops;
|
|
return 0;
|
|
}
|
|
|
|
static const struct file_operations aio_ring_fops = {
|
|
.mmap = aio_ring_mmap,
|
|
};
|
|
|
|
#if IS_ENABLED(CONFIG_MIGRATION)
|
|
static int aio_migratepage(struct address_space *mapping, struct page *new,
|
|
struct page *old, enum migrate_mode mode)
|
|
{
|
|
struct kioctx *ctx;
|
|
unsigned long flags;
|
|
pgoff_t idx;
|
|
int rc;
|
|
|
|
/*
|
|
* We cannot support the _NO_COPY case here, because copy needs to
|
|
* happen under the ctx->completion_lock. That does not work with the
|
|
* migration workflow of MIGRATE_SYNC_NO_COPY.
|
|
*/
|
|
if (mode == MIGRATE_SYNC_NO_COPY)
|
|
return -EINVAL;
|
|
|
|
rc = 0;
|
|
|
|
/* mapping->private_lock here protects against the kioctx teardown. */
|
|
spin_lock(&mapping->private_lock);
|
|
ctx = mapping->private_data;
|
|
if (!ctx) {
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* The ring_lock mutex. The prevents aio_read_events() from writing
|
|
* to the ring's head, and prevents page migration from mucking in
|
|
* a partially initialized kiotx.
|
|
*/
|
|
if (!mutex_trylock(&ctx->ring_lock)) {
|
|
rc = -EAGAIN;
|
|
goto out;
|
|
}
|
|
|
|
idx = old->index;
|
|
if (idx < (pgoff_t)ctx->nr_pages) {
|
|
/* Make sure the old page hasn't already been changed */
|
|
if (ctx->ring_pages[idx] != old)
|
|
rc = -EAGAIN;
|
|
} else
|
|
rc = -EINVAL;
|
|
|
|
if (rc != 0)
|
|
goto out_unlock;
|
|
|
|
/* Writeback must be complete */
|
|
BUG_ON(PageWriteback(old));
|
|
get_page(new);
|
|
|
|
rc = migrate_page_move_mapping(mapping, new, old, 1);
|
|
if (rc != MIGRATEPAGE_SUCCESS) {
|
|
put_page(new);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* Take completion_lock to prevent other writes to the ring buffer
|
|
* while the old page is copied to the new. This prevents new
|
|
* events from being lost.
|
|
*/
|
|
spin_lock_irqsave(&ctx->completion_lock, flags);
|
|
migrate_page_copy(new, old);
|
|
BUG_ON(ctx->ring_pages[idx] != old);
|
|
ctx->ring_pages[idx] = new;
|
|
spin_unlock_irqrestore(&ctx->completion_lock, flags);
|
|
|
|
/* The old page is no longer accessible. */
|
|
put_page(old);
|
|
|
|
out_unlock:
|
|
mutex_unlock(&ctx->ring_lock);
|
|
out:
|
|
spin_unlock(&mapping->private_lock);
|
|
return rc;
|
|
}
|
|
#endif
|
|
|
|
static const struct address_space_operations aio_ctx_aops = {
|
|
.set_page_dirty = __set_page_dirty_no_writeback,
|
|
#if IS_ENABLED(CONFIG_MIGRATION)
|
|
.migratepage = aio_migratepage,
|
|
#endif
|
|
};
|
|
|
|
static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
|
|
{
|
|
struct aio_ring *ring;
|
|
struct mm_struct *mm = current->mm;
|
|
unsigned long size, unused;
|
|
int nr_pages;
|
|
int i;
|
|
struct file *file;
|
|
|
|
/* Compensate for the ring buffer's head/tail overlap entry */
|
|
nr_events += 2; /* 1 is required, 2 for good luck */
|
|
|
|
size = sizeof(struct aio_ring);
|
|
size += sizeof(struct io_event) * nr_events;
|
|
|
|
nr_pages = PFN_UP(size);
|
|
if (nr_pages < 0)
|
|
return -EINVAL;
|
|
|
|
file = aio_private_file(ctx, nr_pages);
|
|
if (IS_ERR(file)) {
|
|
ctx->aio_ring_file = NULL;
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ctx->aio_ring_file = file;
|
|
nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
|
|
/ sizeof(struct io_event);
|
|
|
|
ctx->ring_pages = ctx->internal_pages;
|
|
if (nr_pages > AIO_RING_PAGES) {
|
|
ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
|
|
GFP_KERNEL);
|
|
if (!ctx->ring_pages) {
|
|
put_aio_ring_file(ctx);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < nr_pages; i++) {
|
|
struct page *page;
|
|
page = find_or_create_page(file->f_mapping,
|
|
i, GFP_HIGHUSER | __GFP_ZERO);
|
|
if (!page)
|
|
break;
|
|
pr_debug("pid(%d) page[%d]->count=%d\n",
|
|
current->pid, i, page_count(page));
|
|
SetPageUptodate(page);
|
|
unlock_page(page);
|
|
|
|
ctx->ring_pages[i] = page;
|
|
}
|
|
ctx->nr_pages = i;
|
|
|
|
if (unlikely(i != nr_pages)) {
|
|
aio_free_ring(ctx);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ctx->mmap_size = nr_pages * PAGE_SIZE;
|
|
pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
|
|
|
|
if (mmap_write_lock_killable(mm)) {
|
|
ctx->mmap_size = 0;
|
|
aio_free_ring(ctx);
|
|
return -EINTR;
|
|
}
|
|
|
|
ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size,
|
|
PROT_READ | PROT_WRITE,
|
|
MAP_SHARED, 0, &unused, NULL);
|
|
mmap_write_unlock(mm);
|
|
if (IS_ERR((void *)ctx->mmap_base)) {
|
|
ctx->mmap_size = 0;
|
|
aio_free_ring(ctx);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
|
|
|
|
ctx->user_id = ctx->mmap_base;
|
|
ctx->nr_events = nr_events; /* trusted copy */
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
ring->nr = nr_events; /* user copy */
|
|
ring->id = ~0U;
|
|
ring->head = ring->tail = 0;
|
|
ring->magic = AIO_RING_MAGIC;
|
|
ring->compat_features = AIO_RING_COMPAT_FEATURES;
|
|
ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
|
|
ring->header_length = sizeof(struct aio_ring);
|
|
kunmap_atomic(ring);
|
|
flush_dcache_page(ctx->ring_pages[0]);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
|
|
#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
|
|
#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
|
|
|
|
void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
|
|
{
|
|
struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw);
|
|
struct kioctx *ctx = req->ki_ctx;
|
|
unsigned long flags;
|
|
|
|
if (WARN_ON_ONCE(!list_empty(&req->ki_list)))
|
|
return;
|
|
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags);
|
|
list_add_tail(&req->ki_list, &ctx->active_reqs);
|
|
req->ki_cancel = cancel;
|
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(kiocb_set_cancel_fn);
|
|
|
|
/*
|
|
* free_ioctx() should be RCU delayed to synchronize against the RCU
|
|
* protected lookup_ioctx() and also needs process context to call
|
|
* aio_free_ring(). Use rcu_work.
|
|
*/
|
|
static void free_ioctx(struct work_struct *work)
|
|
{
|
|
struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx,
|
|
free_rwork);
|
|
pr_debug("freeing %p\n", ctx);
|
|
|
|
aio_free_ring(ctx);
|
|
free_percpu(ctx->cpu);
|
|
percpu_ref_exit(&ctx->reqs);
|
|
percpu_ref_exit(&ctx->users);
|
|
kmem_cache_free(kioctx_cachep, ctx);
|
|
}
|
|
|
|
static void free_ioctx_reqs(struct percpu_ref *ref)
|
|
{
|
|
struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
|
|
|
|
/* At this point we know that there are no any in-flight requests */
|
|
if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count))
|
|
complete(&ctx->rq_wait->comp);
|
|
|
|
/* Synchronize against RCU protected table->table[] dereferences */
|
|
INIT_RCU_WORK(&ctx->free_rwork, free_ioctx);
|
|
queue_rcu_work(system_wq, &ctx->free_rwork);
|
|
}
|
|
|
|
/*
|
|
* When this function runs, the kioctx has been removed from the "hash table"
|
|
* and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
|
|
* now it's safe to cancel any that need to be.
|
|
*/
|
|
static void free_ioctx_users(struct percpu_ref *ref)
|
|
{
|
|
struct kioctx *ctx = container_of(ref, struct kioctx, users);
|
|
struct aio_kiocb *req;
|
|
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
|
|
while (!list_empty(&ctx->active_reqs)) {
|
|
req = list_first_entry(&ctx->active_reqs,
|
|
struct aio_kiocb, ki_list);
|
|
req->ki_cancel(&req->rw);
|
|
list_del_init(&req->ki_list);
|
|
}
|
|
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
percpu_ref_kill(&ctx->reqs);
|
|
percpu_ref_put(&ctx->reqs);
|
|
}
|
|
|
|
static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
|
|
{
|
|
unsigned i, new_nr;
|
|
struct kioctx_table *table, *old;
|
|
struct aio_ring *ring;
|
|
|
|
spin_lock(&mm->ioctx_lock);
|
|
table = rcu_dereference_raw(mm->ioctx_table);
|
|
|
|
while (1) {
|
|
if (table)
|
|
for (i = 0; i < table->nr; i++)
|
|
if (!rcu_access_pointer(table->table[i])) {
|
|
ctx->id = i;
|
|
rcu_assign_pointer(table->table[i], ctx);
|
|
spin_unlock(&mm->ioctx_lock);
|
|
|
|
/* While kioctx setup is in progress,
|
|
* we are protected from page migration
|
|
* changes ring_pages by ->ring_lock.
|
|
*/
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
ring->id = ctx->id;
|
|
kunmap_atomic(ring);
|
|
return 0;
|
|
}
|
|
|
|
new_nr = (table ? table->nr : 1) * 4;
|
|
spin_unlock(&mm->ioctx_lock);
|
|
|
|
table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) *
|
|
new_nr, GFP_KERNEL);
|
|
if (!table)
|
|
return -ENOMEM;
|
|
|
|
table->nr = new_nr;
|
|
|
|
spin_lock(&mm->ioctx_lock);
|
|
old = rcu_dereference_raw(mm->ioctx_table);
|
|
|
|
if (!old) {
|
|
rcu_assign_pointer(mm->ioctx_table, table);
|
|
} else if (table->nr > old->nr) {
|
|
memcpy(table->table, old->table,
|
|
old->nr * sizeof(struct kioctx *));
|
|
|
|
rcu_assign_pointer(mm->ioctx_table, table);
|
|
kfree_rcu(old, rcu);
|
|
} else {
|
|
kfree(table);
|
|
table = old;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void aio_nr_sub(unsigned nr)
|
|
{
|
|
spin_lock(&aio_nr_lock);
|
|
if (WARN_ON(aio_nr - nr > aio_nr))
|
|
aio_nr = 0;
|
|
else
|
|
aio_nr -= nr;
|
|
spin_unlock(&aio_nr_lock);
|
|
}
|
|
|
|
/* ioctx_alloc
|
|
* Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
|
|
*/
|
|
static struct kioctx *ioctx_alloc(unsigned nr_events)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct kioctx *ctx;
|
|
int err = -ENOMEM;
|
|
|
|
/*
|
|
* Store the original nr_events -- what userspace passed to io_setup(),
|
|
* for counting against the global limit -- before it changes.
|
|
*/
|
|
unsigned int max_reqs = nr_events;
|
|
|
|
/*
|
|
* We keep track of the number of available ringbuffer slots, to prevent
|
|
* overflow (reqs_available), and we also use percpu counters for this.
|
|
*
|
|
* So since up to half the slots might be on other cpu's percpu counters
|
|
* and unavailable, double nr_events so userspace sees what they
|
|
* expected: additionally, we move req_batch slots to/from percpu
|
|
* counters at a time, so make sure that isn't 0:
|
|
*/
|
|
nr_events = max(nr_events, num_possible_cpus() * 4);
|
|
nr_events *= 2;
|
|
|
|
/* Prevent overflows */
|
|
if (nr_events > (0x10000000U / sizeof(struct io_event))) {
|
|
pr_debug("ENOMEM: nr_events too high\n");
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
if (!nr_events || (unsigned long)max_reqs > aio_max_nr)
|
|
return ERR_PTR(-EAGAIN);
|
|
|
|
ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
|
|
if (!ctx)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
ctx->max_reqs = max_reqs;
|
|
|
|
spin_lock_init(&ctx->ctx_lock);
|
|
spin_lock_init(&ctx->completion_lock);
|
|
mutex_init(&ctx->ring_lock);
|
|
/* Protect against page migration throughout kiotx setup by keeping
|
|
* the ring_lock mutex held until setup is complete. */
|
|
mutex_lock(&ctx->ring_lock);
|
|
init_waitqueue_head(&ctx->wait);
|
|
|
|
INIT_LIST_HEAD(&ctx->active_reqs);
|
|
|
|
if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
|
|
goto err;
|
|
|
|
if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
|
|
goto err;
|
|
|
|
ctx->cpu = alloc_percpu(struct kioctx_cpu);
|
|
if (!ctx->cpu)
|
|
goto err;
|
|
|
|
err = aio_setup_ring(ctx, nr_events);
|
|
if (err < 0)
|
|
goto err;
|
|
|
|
atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
|
|
ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
|
|
if (ctx->req_batch < 1)
|
|
ctx->req_batch = 1;
|
|
|
|
/* limit the number of system wide aios */
|
|
spin_lock(&aio_nr_lock);
|
|
if (aio_nr + ctx->max_reqs > aio_max_nr ||
|
|
aio_nr + ctx->max_reqs < aio_nr) {
|
|
spin_unlock(&aio_nr_lock);
|
|
err = -EAGAIN;
|
|
goto err_ctx;
|
|
}
|
|
aio_nr += ctx->max_reqs;
|
|
spin_unlock(&aio_nr_lock);
|
|
|
|
percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
|
|
percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
|
|
|
|
err = ioctx_add_table(ctx, mm);
|
|
if (err)
|
|
goto err_cleanup;
|
|
|
|
/* Release the ring_lock mutex now that all setup is complete. */
|
|
mutex_unlock(&ctx->ring_lock);
|
|
|
|
pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
|
|
ctx, ctx->user_id, mm, ctx->nr_events);
|
|
return ctx;
|
|
|
|
err_cleanup:
|
|
aio_nr_sub(ctx->max_reqs);
|
|
err_ctx:
|
|
atomic_set(&ctx->dead, 1);
|
|
if (ctx->mmap_size)
|
|
vm_munmap(ctx->mmap_base, ctx->mmap_size);
|
|
aio_free_ring(ctx);
|
|
err:
|
|
mutex_unlock(&ctx->ring_lock);
|
|
free_percpu(ctx->cpu);
|
|
percpu_ref_exit(&ctx->reqs);
|
|
percpu_ref_exit(&ctx->users);
|
|
kmem_cache_free(kioctx_cachep, ctx);
|
|
pr_debug("error allocating ioctx %d\n", err);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
/* kill_ioctx
|
|
* Cancels all outstanding aio requests on an aio context. Used
|
|
* when the processes owning a context have all exited to encourage
|
|
* the rapid destruction of the kioctx.
|
|
*/
|
|
static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
|
|
struct ctx_rq_wait *wait)
|
|
{
|
|
struct kioctx_table *table;
|
|
|
|
spin_lock(&mm->ioctx_lock);
|
|
if (atomic_xchg(&ctx->dead, 1)) {
|
|
spin_unlock(&mm->ioctx_lock);
|
|
return -EINVAL;
|
|
}
|
|
|
|
table = rcu_dereference_raw(mm->ioctx_table);
|
|
WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id]));
|
|
RCU_INIT_POINTER(table->table[ctx->id], NULL);
|
|
spin_unlock(&mm->ioctx_lock);
|
|
|
|
/* free_ioctx_reqs() will do the necessary RCU synchronization */
|
|
wake_up_all(&ctx->wait);
|
|
|
|
/*
|
|
* It'd be more correct to do this in free_ioctx(), after all
|
|
* the outstanding kiocbs have finished - but by then io_destroy
|
|
* has already returned, so io_setup() could potentially return
|
|
* -EAGAIN with no ioctxs actually in use (as far as userspace
|
|
* could tell).
|
|
*/
|
|
aio_nr_sub(ctx->max_reqs);
|
|
|
|
if (ctx->mmap_size)
|
|
vm_munmap(ctx->mmap_base, ctx->mmap_size);
|
|
|
|
ctx->rq_wait = wait;
|
|
percpu_ref_kill(&ctx->users);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* exit_aio: called when the last user of mm goes away. At this point, there is
|
|
* no way for any new requests to be submited or any of the io_* syscalls to be
|
|
* called on the context.
|
|
*
|
|
* There may be outstanding kiocbs, but free_ioctx() will explicitly wait on
|
|
* them.
|
|
*/
|
|
void exit_aio(struct mm_struct *mm)
|
|
{
|
|
struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);
|
|
struct ctx_rq_wait wait;
|
|
int i, skipped;
|
|
|
|
if (!table)
|
|
return;
|
|
|
|
atomic_set(&wait.count, table->nr);
|
|
init_completion(&wait.comp);
|
|
|
|
skipped = 0;
|
|
for (i = 0; i < table->nr; ++i) {
|
|
struct kioctx *ctx =
|
|
rcu_dereference_protected(table->table[i], true);
|
|
|
|
if (!ctx) {
|
|
skipped++;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* We don't need to bother with munmap() here - exit_mmap(mm)
|
|
* is coming and it'll unmap everything. And we simply can't,
|
|
* this is not necessarily our ->mm.
|
|
* Since kill_ioctx() uses non-zero ->mmap_size as indicator
|
|
* that it needs to unmap the area, just set it to 0.
|
|
*/
|
|
ctx->mmap_size = 0;
|
|
kill_ioctx(mm, ctx, &wait);
|
|
}
|
|
|
|
if (!atomic_sub_and_test(skipped, &wait.count)) {
|
|
/* Wait until all IO for the context are done. */
|
|
wait_for_completion(&wait.comp);
|
|
}
|
|
|
|
RCU_INIT_POINTER(mm->ioctx_table, NULL);
|
|
kfree(table);
|
|
}
|
|
|
|
static void put_reqs_available(struct kioctx *ctx, unsigned nr)
|
|
{
|
|
struct kioctx_cpu *kcpu;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
kcpu = this_cpu_ptr(ctx->cpu);
|
|
kcpu->reqs_available += nr;
|
|
|
|
while (kcpu->reqs_available >= ctx->req_batch * 2) {
|
|
kcpu->reqs_available -= ctx->req_batch;
|
|
atomic_add(ctx->req_batch, &ctx->reqs_available);
|
|
}
|
|
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static bool __get_reqs_available(struct kioctx *ctx)
|
|
{
|
|
struct kioctx_cpu *kcpu;
|
|
bool ret = false;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
kcpu = this_cpu_ptr(ctx->cpu);
|
|
if (!kcpu->reqs_available) {
|
|
int old, avail = atomic_read(&ctx->reqs_available);
|
|
|
|
do {
|
|
if (avail < ctx->req_batch)
|
|
goto out;
|
|
|
|
old = avail;
|
|
avail = atomic_cmpxchg(&ctx->reqs_available,
|
|
avail, avail - ctx->req_batch);
|
|
} while (avail != old);
|
|
|
|
kcpu->reqs_available += ctx->req_batch;
|
|
}
|
|
|
|
ret = true;
|
|
kcpu->reqs_available--;
|
|
out:
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
}
|
|
|
|
/* refill_reqs_available
|
|
* Updates the reqs_available reference counts used for tracking the
|
|
* number of free slots in the completion ring. This can be called
|
|
* from aio_complete() (to optimistically update reqs_available) or
|
|
* from aio_get_req() (the we're out of events case). It must be
|
|
* called holding ctx->completion_lock.
|
|
*/
|
|
static void refill_reqs_available(struct kioctx *ctx, unsigned head,
|
|
unsigned tail)
|
|
{
|
|
unsigned events_in_ring, completed;
|
|
|
|
/* Clamp head since userland can write to it. */
|
|
head %= ctx->nr_events;
|
|
if (head <= tail)
|
|
events_in_ring = tail - head;
|
|
else
|
|
events_in_ring = ctx->nr_events - (head - tail);
|
|
|
|
completed = ctx->completed_events;
|
|
if (events_in_ring < completed)
|
|
completed -= events_in_ring;
|
|
else
|
|
completed = 0;
|
|
|
|
if (!completed)
|
|
return;
|
|
|
|
ctx->completed_events -= completed;
|
|
put_reqs_available(ctx, completed);
|
|
}
|
|
|
|
/* user_refill_reqs_available
|
|
* Called to refill reqs_available when aio_get_req() encounters an
|
|
* out of space in the completion ring.
|
|
*/
|
|
static void user_refill_reqs_available(struct kioctx *ctx)
|
|
{
|
|
spin_lock_irq(&ctx->completion_lock);
|
|
if (ctx->completed_events) {
|
|
struct aio_ring *ring;
|
|
unsigned head;
|
|
|
|
/* Access of ring->head may race with aio_read_events_ring()
|
|
* here, but that's okay since whether we read the old version
|
|
* or the new version, and either will be valid. The important
|
|
* part is that head cannot pass tail since we prevent
|
|
* aio_complete() from updating tail by holding
|
|
* ctx->completion_lock. Even if head is invalid, the check
|
|
* against ctx->completed_events below will make sure we do the
|
|
* safe/right thing.
|
|
*/
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
head = ring->head;
|
|
kunmap_atomic(ring);
|
|
|
|
refill_reqs_available(ctx, head, ctx->tail);
|
|
}
|
|
|
|
spin_unlock_irq(&ctx->completion_lock);
|
|
}
|
|
|
|
static bool get_reqs_available(struct kioctx *ctx)
|
|
{
|
|
if (__get_reqs_available(ctx))
|
|
return true;
|
|
user_refill_reqs_available(ctx);
|
|
return __get_reqs_available(ctx);
|
|
}
|
|
|
|
/* aio_get_req
|
|
* Allocate a slot for an aio request.
|
|
* Returns NULL if no requests are free.
|
|
*
|
|
* The refcount is initialized to 2 - one for the async op completion,
|
|
* one for the synchronous code that does this.
|
|
*/
|
|
static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
|
|
{
|
|
struct aio_kiocb *req;
|
|
|
|
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
|
|
if (unlikely(!req))
|
|
return NULL;
|
|
|
|
if (unlikely(!get_reqs_available(ctx))) {
|
|
kmem_cache_free(kiocb_cachep, req);
|
|
return NULL;
|
|
}
|
|
|
|
percpu_ref_get(&ctx->reqs);
|
|
req->ki_ctx = ctx;
|
|
INIT_LIST_HEAD(&req->ki_list);
|
|
refcount_set(&req->ki_refcnt, 2);
|
|
req->ki_eventfd = NULL;
|
|
return req;
|
|
}
|
|
|
|
static struct kioctx *lookup_ioctx(unsigned long ctx_id)
|
|
{
|
|
struct aio_ring __user *ring = (void __user *)ctx_id;
|
|
struct mm_struct *mm = current->mm;
|
|
struct kioctx *ctx, *ret = NULL;
|
|
struct kioctx_table *table;
|
|
unsigned id;
|
|
|
|
if (get_user(id, &ring->id))
|
|
return NULL;
|
|
|
|
rcu_read_lock();
|
|
table = rcu_dereference(mm->ioctx_table);
|
|
|
|
if (!table || id >= table->nr)
|
|
goto out;
|
|
|
|
id = array_index_nospec(id, table->nr);
|
|
ctx = rcu_dereference(table->table[id]);
|
|
if (ctx && ctx->user_id == ctx_id) {
|
|
if (percpu_ref_tryget_live(&ctx->users))
|
|
ret = ctx;
|
|
}
|
|
out:
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
|
|
static inline void iocb_destroy(struct aio_kiocb *iocb)
|
|
{
|
|
if (iocb->ki_eventfd)
|
|
eventfd_ctx_put(iocb->ki_eventfd);
|
|
if (iocb->ki_filp)
|
|
fput(iocb->ki_filp);
|
|
percpu_ref_put(&iocb->ki_ctx->reqs);
|
|
kmem_cache_free(kiocb_cachep, iocb);
|
|
}
|
|
|
|
/* aio_complete
|
|
* Called when the io request on the given iocb is complete.
|
|
*/
|
|
static void aio_complete(struct aio_kiocb *iocb)
|
|
{
|
|
struct kioctx *ctx = iocb->ki_ctx;
|
|
struct aio_ring *ring;
|
|
struct io_event *ev_page, *event;
|
|
unsigned tail, pos, head;
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* Add a completion event to the ring buffer. Must be done holding
|
|
* ctx->completion_lock to prevent other code from messing with the tail
|
|
* pointer since we might be called from irq context.
|
|
*/
|
|
spin_lock_irqsave(&ctx->completion_lock, flags);
|
|
|
|
tail = ctx->tail;
|
|
pos = tail + AIO_EVENTS_OFFSET;
|
|
|
|
if (++tail >= ctx->nr_events)
|
|
tail = 0;
|
|
|
|
ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
|
|
event = ev_page + pos % AIO_EVENTS_PER_PAGE;
|
|
|
|
*event = iocb->ki_res;
|
|
|
|
kunmap_atomic(ev_page);
|
|
flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
|
|
|
|
pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\n", ctx, tail, iocb,
|
|
(void __user *)(unsigned long)iocb->ki_res.obj,
|
|
iocb->ki_res.data, iocb->ki_res.res, iocb->ki_res.res2);
|
|
|
|
/* after flagging the request as done, we
|
|
* must never even look at it again
|
|
*/
|
|
smp_wmb(); /* make event visible before updating tail */
|
|
|
|
ctx->tail = tail;
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
head = ring->head;
|
|
ring->tail = tail;
|
|
kunmap_atomic(ring);
|
|
flush_dcache_page(ctx->ring_pages[0]);
|
|
|
|
ctx->completed_events++;
|
|
if (ctx->completed_events > 1)
|
|
refill_reqs_available(ctx, head, tail);
|
|
spin_unlock_irqrestore(&ctx->completion_lock, flags);
|
|
|
|
pr_debug("added to ring %p at [%u]\n", iocb, tail);
|
|
|
|
/*
|
|
* Check if the user asked us to deliver the result through an
|
|
* eventfd. The eventfd_signal() function is safe to be called
|
|
* from IRQ context.
|
|
*/
|
|
if (iocb->ki_eventfd)
|
|
eventfd_signal(iocb->ki_eventfd, 1);
|
|
|
|
/*
|
|
* We have to order our ring_info tail store above and test
|
|
* of the wait list below outside the wait lock. This is
|
|
* like in wake_up_bit() where clearing a bit has to be
|
|
* ordered with the unlocked test.
|
|
*/
|
|
smp_mb();
|
|
|
|
if (waitqueue_active(&ctx->wait))
|
|
wake_up(&ctx->wait);
|
|
}
|
|
|
|
static inline void iocb_put(struct aio_kiocb *iocb)
|
|
{
|
|
if (refcount_dec_and_test(&iocb->ki_refcnt)) {
|
|
aio_complete(iocb);
|
|
iocb_destroy(iocb);
|
|
}
|
|
}
|
|
|
|
/* aio_read_events_ring
|
|
* Pull an event off of the ioctx's event ring. Returns the number of
|
|
* events fetched
|
|
*/
|
|
static long aio_read_events_ring(struct kioctx *ctx,
|
|
struct io_event __user *event, long nr)
|
|
{
|
|
struct aio_ring *ring;
|
|
unsigned head, tail, pos;
|
|
long ret = 0;
|
|
int copy_ret;
|
|
|
|
/*
|
|
* The mutex can block and wake us up and that will cause
|
|
* wait_event_interruptible_hrtimeout() to schedule without sleeping
|
|
* and repeat. This should be rare enough that it doesn't cause
|
|
* peformance issues. See the comment in read_events() for more detail.
|
|
*/
|
|
sched_annotate_sleep();
|
|
mutex_lock(&ctx->ring_lock);
|
|
|
|
/* Access to ->ring_pages here is protected by ctx->ring_lock. */
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
head = ring->head;
|
|
tail = ring->tail;
|
|
kunmap_atomic(ring);
|
|
|
|
/*
|
|
* Ensure that once we've read the current tail pointer, that
|
|
* we also see the events that were stored up to the tail.
|
|
*/
|
|
smp_rmb();
|
|
|
|
pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
|
|
|
|
if (head == tail)
|
|
goto out;
|
|
|
|
head %= ctx->nr_events;
|
|
tail %= ctx->nr_events;
|
|
|
|
while (ret < nr) {
|
|
long avail;
|
|
struct io_event *ev;
|
|
struct page *page;
|
|
|
|
avail = (head <= tail ? tail : ctx->nr_events) - head;
|
|
if (head == tail)
|
|
break;
|
|
|
|
pos = head + AIO_EVENTS_OFFSET;
|
|
page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
|
|
pos %= AIO_EVENTS_PER_PAGE;
|
|
|
|
avail = min(avail, nr - ret);
|
|
avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
|
|
|
|
ev = kmap(page);
|
|
copy_ret = copy_to_user(event + ret, ev + pos,
|
|
sizeof(*ev) * avail);
|
|
kunmap(page);
|
|
|
|
if (unlikely(copy_ret)) {
|
|
ret = -EFAULT;
|
|
goto out;
|
|
}
|
|
|
|
ret += avail;
|
|
head += avail;
|
|
head %= ctx->nr_events;
|
|
}
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
ring->head = head;
|
|
kunmap_atomic(ring);
|
|
flush_dcache_page(ctx->ring_pages[0]);
|
|
|
|
pr_debug("%li h%u t%u\n", ret, head, tail);
|
|
out:
|
|
mutex_unlock(&ctx->ring_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,
|
|
struct io_event __user *event, long *i)
|
|
{
|
|
long ret = aio_read_events_ring(ctx, event + *i, nr - *i);
|
|
|
|
if (ret > 0)
|
|
*i += ret;
|
|
|
|
if (unlikely(atomic_read(&ctx->dead)))
|
|
ret = -EINVAL;
|
|
|
|
if (!*i)
|
|
*i = ret;
|
|
|
|
return ret < 0 || *i >= min_nr;
|
|
}
|
|
|
|
static long read_events(struct kioctx *ctx, long min_nr, long nr,
|
|
struct io_event __user *event,
|
|
ktime_t until)
|
|
{
|
|
long ret = 0;
|
|
|
|
/*
|
|
* Note that aio_read_events() is being called as the conditional - i.e.
|
|
* we're calling it after prepare_to_wait() has set task state to
|
|
* TASK_INTERRUPTIBLE.
|
|
*
|
|
* But aio_read_events() can block, and if it blocks it's going to flip
|
|
* the task state back to TASK_RUNNING.
|
|
*
|
|
* This should be ok, provided it doesn't flip the state back to
|
|
* TASK_RUNNING and return 0 too much - that causes us to spin. That
|
|
* will only happen if the mutex_lock() call blocks, and we then find
|
|
* the ringbuffer empty. So in practice we should be ok, but it's
|
|
* something to be aware of when touching this code.
|
|
*/
|
|
if (until == 0)
|
|
aio_read_events(ctx, min_nr, nr, event, &ret);
|
|
else
|
|
wait_event_interruptible_hrtimeout(ctx->wait,
|
|
aio_read_events(ctx, min_nr, nr, event, &ret),
|
|
until);
|
|
return ret;
|
|
}
|
|
|
|
/* sys_io_setup:
|
|
* Create an aio_context capable of receiving at least nr_events.
|
|
* ctxp must not point to an aio_context that already exists, and
|
|
* must be initialized to 0 prior to the call. On successful
|
|
* creation of the aio_context, *ctxp is filled in with the resulting
|
|
* handle. May fail with -EINVAL if *ctxp is not initialized,
|
|
* if the specified nr_events exceeds internal limits. May fail
|
|
* with -EAGAIN if the specified nr_events exceeds the user's limit
|
|
* of available events. May fail with -ENOMEM if insufficient kernel
|
|
* resources are available. May fail with -EFAULT if an invalid
|
|
* pointer is passed for ctxp. Will fail with -ENOSYS if not
|
|
* implemented.
|
|
*/
|
|
SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
|
|
{
|
|
struct kioctx *ioctx = NULL;
|
|
unsigned long ctx;
|
|
long ret;
|
|
|
|
ret = get_user(ctx, ctxp);
|
|
if (unlikely(ret))
|
|
goto out;
|
|
|
|
ret = -EINVAL;
|
|
if (unlikely(ctx || nr_events == 0)) {
|
|
pr_debug("EINVAL: ctx %lu nr_events %u\n",
|
|
ctx, nr_events);
|
|
goto out;
|
|
}
|
|
|
|
ioctx = ioctx_alloc(nr_events);
|
|
ret = PTR_ERR(ioctx);
|
|
if (!IS_ERR(ioctx)) {
|
|
ret = put_user(ioctx->user_id, ctxp);
|
|
if (ret)
|
|
kill_ioctx(current->mm, ioctx, NULL);
|
|
percpu_ref_put(&ioctx->users);
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)
|
|
{
|
|
struct kioctx *ioctx = NULL;
|
|
unsigned long ctx;
|
|
long ret;
|
|
|
|
ret = get_user(ctx, ctx32p);
|
|
if (unlikely(ret))
|
|
goto out;
|
|
|
|
ret = -EINVAL;
|
|
if (unlikely(ctx || nr_events == 0)) {
|
|
pr_debug("EINVAL: ctx %lu nr_events %u\n",
|
|
ctx, nr_events);
|
|
goto out;
|
|
}
|
|
|
|
ioctx = ioctx_alloc(nr_events);
|
|
ret = PTR_ERR(ioctx);
|
|
if (!IS_ERR(ioctx)) {
|
|
/* truncating is ok because it's a user address */
|
|
ret = put_user((u32)ioctx->user_id, ctx32p);
|
|
if (ret)
|
|
kill_ioctx(current->mm, ioctx, NULL);
|
|
percpu_ref_put(&ioctx->users);
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
/* sys_io_destroy:
|
|
* Destroy the aio_context specified. May cancel any outstanding
|
|
* AIOs and block on completion. Will fail with -ENOSYS if not
|
|
* implemented. May fail with -EINVAL if the context pointed to
|
|
* is invalid.
|
|
*/
|
|
SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
|
|
{
|
|
struct kioctx *ioctx = lookup_ioctx(ctx);
|
|
if (likely(NULL != ioctx)) {
|
|
struct ctx_rq_wait wait;
|
|
int ret;
|
|
|
|
init_completion(&wait.comp);
|
|
atomic_set(&wait.count, 1);
|
|
|
|
/* Pass requests_done to kill_ioctx() where it can be set
|
|
* in a thread-safe way. If we try to set it here then we have
|
|
* a race condition if two io_destroy() called simultaneously.
|
|
*/
|
|
ret = kill_ioctx(current->mm, ioctx, &wait);
|
|
percpu_ref_put(&ioctx->users);
|
|
|
|
/* Wait until all IO for the context are done. Otherwise kernel
|
|
* keep using user-space buffers even if user thinks the context
|
|
* is destroyed.
|
|
*/
|
|
if (!ret)
|
|
wait_for_completion(&wait.comp);
|
|
|
|
return ret;
|
|
}
|
|
pr_debug("EINVAL: invalid context id\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
static void aio_remove_iocb(struct aio_kiocb *iocb)
|
|
{
|
|
struct kioctx *ctx = iocb->ki_ctx;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags);
|
|
list_del(&iocb->ki_list);
|
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
|
|
}
|
|
|
|
static void aio_complete_rw(struct kiocb *kiocb, long res, long res2)
|
|
{
|
|
struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, rw);
|
|
|
|
if (!list_empty_careful(&iocb->ki_list))
|
|
aio_remove_iocb(iocb);
|
|
|
|
if (kiocb->ki_flags & IOCB_WRITE) {
|
|
struct inode *inode = file_inode(kiocb->ki_filp);
|
|
|
|
/*
|
|
* Tell lockdep we inherited freeze protection from submission
|
|
* thread.
|
|
*/
|
|
if (S_ISREG(inode->i_mode))
|
|
__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
|
|
file_end_write(kiocb->ki_filp);
|
|
}
|
|
|
|
iocb->ki_res.res = res;
|
|
iocb->ki_res.res2 = res2;
|
|
iocb_put(iocb);
|
|
}
|
|
|
|
static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
|
|
{
|
|
int ret;
|
|
|
|
req->ki_complete = aio_complete_rw;
|
|
req->private = NULL;
|
|
req->ki_pos = iocb->aio_offset;
|
|
req->ki_flags = iocb_flags(req->ki_filp);
|
|
if (iocb->aio_flags & IOCB_FLAG_RESFD)
|
|
req->ki_flags |= IOCB_EVENTFD;
|
|
req->ki_hint = ki_hint_validate(file_write_hint(req->ki_filp));
|
|
if (iocb->aio_flags & IOCB_FLAG_IOPRIO) {
|
|
/*
|
|
* If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then
|
|
* aio_reqprio is interpreted as an I/O scheduling
|
|
* class and priority.
|
|
*/
|
|
ret = ioprio_check_cap(iocb->aio_reqprio);
|
|
if (ret) {
|
|
pr_debug("aio ioprio check cap error: %d\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
req->ki_ioprio = iocb->aio_reqprio;
|
|
} else
|
|
req->ki_ioprio = get_current_ioprio();
|
|
|
|
ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags);
|
|
if (unlikely(ret))
|
|
return ret;
|
|
|
|
req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t aio_setup_rw(int rw, const struct iocb *iocb,
|
|
struct iovec **iovec, bool vectored, bool compat,
|
|
struct iov_iter *iter)
|
|
{
|
|
void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;
|
|
size_t len = iocb->aio_nbytes;
|
|
|
|
if (!vectored) {
|
|
ssize_t ret = import_single_range(rw, buf, len, *iovec, iter);
|
|
*iovec = NULL;
|
|
return ret;
|
|
}
|
|
|
|
return __import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter, compat);
|
|
}
|
|
|
|
static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
|
|
{
|
|
switch (ret) {
|
|
case -EIOCBQUEUED:
|
|
break;
|
|
case -ERESTARTSYS:
|
|
case -ERESTARTNOINTR:
|
|
case -ERESTARTNOHAND:
|
|
case -ERESTART_RESTARTBLOCK:
|
|
/*
|
|
* There's no easy way to restart the syscall since other AIO's
|
|
* may be already running. Just fail this IO with EINTR.
|
|
*/
|
|
ret = -EINTR;
|
|
fallthrough;
|
|
default:
|
|
req->ki_complete(req, ret, 0);
|
|
}
|
|
}
|
|
|
|
static int aio_read(struct kiocb *req, const struct iocb *iocb,
|
|
bool vectored, bool compat)
|
|
{
|
|
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
|
|
struct iov_iter iter;
|
|
struct file *file;
|
|
int ret;
|
|
|
|
ret = aio_prep_rw(req, iocb);
|
|
if (ret)
|
|
return ret;
|
|
file = req->ki_filp;
|
|
if (unlikely(!(file->f_mode & FMODE_READ)))
|
|
return -EBADF;
|
|
ret = -EINVAL;
|
|
if (unlikely(!file->f_op->read_iter))
|
|
return -EINVAL;
|
|
|
|
ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter);
|
|
if (ret < 0)
|
|
return ret;
|
|
ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));
|
|
if (!ret)
|
|
aio_rw_done(req, call_read_iter(file, req, &iter));
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
|
|
static int aio_write(struct kiocb *req, const struct iocb *iocb,
|
|
bool vectored, bool compat)
|
|
{
|
|
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
|
|
struct iov_iter iter;
|
|
struct file *file;
|
|
int ret;
|
|
|
|
ret = aio_prep_rw(req, iocb);
|
|
if (ret)
|
|
return ret;
|
|
file = req->ki_filp;
|
|
|
|
if (unlikely(!(file->f_mode & FMODE_WRITE)))
|
|
return -EBADF;
|
|
if (unlikely(!file->f_op->write_iter))
|
|
return -EINVAL;
|
|
|
|
ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter);
|
|
if (ret < 0)
|
|
return ret;
|
|
ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
|
|
if (!ret) {
|
|
/*
|
|
* Open-code file_start_write here to grab freeze protection,
|
|
* which will be released by another thread in
|
|
* aio_complete_rw(). Fool lockdep by telling it the lock got
|
|
* released so that it doesn't complain about the held lock when
|
|
* we return to userspace.
|
|
*/
|
|
if (S_ISREG(file_inode(file)->i_mode)) {
|
|
sb_start_write(file_inode(file)->i_sb);
|
|
__sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE);
|
|
}
|
|
req->ki_flags |= IOCB_WRITE;
|
|
aio_rw_done(req, call_write_iter(file, req, &iter));
|
|
}
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
|
|
static void aio_fsync_work(struct work_struct *work)
|
|
{
|
|
struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, fsync.work);
|
|
const struct cred *old_cred = override_creds(iocb->fsync.creds);
|
|
|
|
iocb->ki_res.res = vfs_fsync(iocb->fsync.file, iocb->fsync.datasync);
|
|
revert_creds(old_cred);
|
|
put_cred(iocb->fsync.creds);
|
|
iocb_put(iocb);
|
|
}
|
|
|
|
static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
|
|
bool datasync)
|
|
{
|
|
if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||
|
|
iocb->aio_rw_flags))
|
|
return -EINVAL;
|
|
|
|
if (unlikely(!req->file->f_op->fsync))
|
|
return -EINVAL;
|
|
|
|
req->creds = prepare_creds();
|
|
if (!req->creds)
|
|
return -ENOMEM;
|
|
|
|
req->datasync = datasync;
|
|
INIT_WORK(&req->work, aio_fsync_work);
|
|
schedule_work(&req->work);
|
|
return 0;
|
|
}
|
|
|
|
static void aio_poll_put_work(struct work_struct *work)
|
|
{
|
|
struct poll_iocb *req = container_of(work, struct poll_iocb, work);
|
|
struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
|
|
|
|
iocb_put(iocb);
|
|
}
|
|
|
|
static void aio_poll_complete_work(struct work_struct *work)
|
|
{
|
|
struct poll_iocb *req = container_of(work, struct poll_iocb, work);
|
|
struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
|
|
struct poll_table_struct pt = { ._key = req->events };
|
|
struct kioctx *ctx = iocb->ki_ctx;
|
|
__poll_t mask = 0;
|
|
|
|
if (!READ_ONCE(req->cancelled))
|
|
mask = vfs_poll(req->file, &pt) & req->events;
|
|
|
|
/*
|
|
* Note that ->ki_cancel callers also delete iocb from active_reqs after
|
|
* calling ->ki_cancel. We need the ctx_lock roundtrip here to
|
|
* synchronize with them. In the cancellation case the list_del_init
|
|
* itself is not actually needed, but harmless so we keep it in to
|
|
* avoid further branches in the fast path.
|
|
*/
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
if (!mask && !READ_ONCE(req->cancelled)) {
|
|
add_wait_queue(req->head, &req->wait);
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
return;
|
|
}
|
|
list_del_init(&iocb->ki_list);
|
|
iocb->ki_res.res = mangle_poll(mask);
|
|
req->done = true;
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
iocb_put(iocb);
|
|
}
|
|
|
|
/* assumes we are called with irqs disabled */
|
|
static int aio_poll_cancel(struct kiocb *iocb)
|
|
{
|
|
struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw);
|
|
struct poll_iocb *req = &aiocb->poll;
|
|
|
|
spin_lock(&req->head->lock);
|
|
WRITE_ONCE(req->cancelled, true);
|
|
if (!list_empty(&req->wait.entry)) {
|
|
list_del_init(&req->wait.entry);
|
|
schedule_work(&aiocb->poll.work);
|
|
}
|
|
spin_unlock(&req->head->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
|
|
void *key)
|
|
{
|
|
struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);
|
|
struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
|
|
__poll_t mask = key_to_poll(key);
|
|
unsigned long flags;
|
|
|
|
/* for instances that support it check for an event match first: */
|
|
if (mask && !(mask & req->events))
|
|
return 0;
|
|
|
|
list_del_init(&req->wait.entry);
|
|
|
|
if (mask && spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {
|
|
struct kioctx *ctx = iocb->ki_ctx;
|
|
|
|
/*
|
|
* Try to complete the iocb inline if we can. Use
|
|
* irqsave/irqrestore because not all filesystems (e.g. fuse)
|
|
* call this function with IRQs disabled and because IRQs
|
|
* have to be disabled before ctx_lock is obtained.
|
|
*/
|
|
list_del(&iocb->ki_list);
|
|
iocb->ki_res.res = mangle_poll(mask);
|
|
req->done = true;
|
|
if (iocb->ki_eventfd && eventfd_signal_count()) {
|
|
iocb = NULL;
|
|
INIT_WORK(&req->work, aio_poll_put_work);
|
|
schedule_work(&req->work);
|
|
}
|
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
|
|
if (iocb)
|
|
iocb_put(iocb);
|
|
} else {
|
|
schedule_work(&req->work);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
struct aio_poll_table {
|
|
struct poll_table_struct pt;
|
|
struct aio_kiocb *iocb;
|
|
int error;
|
|
};
|
|
|
|
static void
|
|
aio_poll_queue_proc(struct file *file, struct wait_queue_head *head,
|
|
struct poll_table_struct *p)
|
|
{
|
|
struct aio_poll_table *pt = container_of(p, struct aio_poll_table, pt);
|
|
|
|
/* multiple wait queues per file are not supported */
|
|
if (unlikely(pt->iocb->poll.head)) {
|
|
pt->error = -EINVAL;
|
|
return;
|
|
}
|
|
|
|
pt->error = 0;
|
|
pt->iocb->poll.head = head;
|
|
add_wait_queue(head, &pt->iocb->poll.wait);
|
|
}
|
|
|
|
static int aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
|
|
{
|
|
struct kioctx *ctx = aiocb->ki_ctx;
|
|
struct poll_iocb *req = &aiocb->poll;
|
|
struct aio_poll_table apt;
|
|
bool cancel = false;
|
|
__poll_t mask;
|
|
|
|
/* reject any unknown events outside the normal event mask. */
|
|
if ((u16)iocb->aio_buf != iocb->aio_buf)
|
|
return -EINVAL;
|
|
/* reject fields that are not defined for poll */
|
|
if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)
|
|
return -EINVAL;
|
|
|
|
INIT_WORK(&req->work, aio_poll_complete_work);
|
|
req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;
|
|
|
|
req->head = NULL;
|
|
req->done = false;
|
|
req->cancelled = false;
|
|
|
|
apt.pt._qproc = aio_poll_queue_proc;
|
|
apt.pt._key = req->events;
|
|
apt.iocb = aiocb;
|
|
apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
|
|
|
|
/* initialized the list so that we can do list_empty checks */
|
|
INIT_LIST_HEAD(&req->wait.entry);
|
|
init_waitqueue_func_entry(&req->wait, aio_poll_wake);
|
|
|
|
mask = vfs_poll(req->file, &apt.pt) & req->events;
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
if (likely(req->head)) {
|
|
spin_lock(&req->head->lock);
|
|
if (unlikely(list_empty(&req->wait.entry))) {
|
|
if (apt.error)
|
|
cancel = true;
|
|
apt.error = 0;
|
|
mask = 0;
|
|
}
|
|
if (mask || apt.error) {
|
|
list_del_init(&req->wait.entry);
|
|
} else if (cancel) {
|
|
WRITE_ONCE(req->cancelled, true);
|
|
} else if (!req->done) { /* actually waiting for an event */
|
|
list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
|
|
aiocb->ki_cancel = aio_poll_cancel;
|
|
}
|
|
spin_unlock(&req->head->lock);
|
|
}
|
|
if (mask) { /* no async, we'd stolen it */
|
|
aiocb->ki_res.res = mangle_poll(mask);
|
|
apt.error = 0;
|
|
}
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
if (mask)
|
|
iocb_put(aiocb);
|
|
return apt.error;
|
|
}
|
|
|
|
static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
|
|
struct iocb __user *user_iocb, struct aio_kiocb *req,
|
|
bool compat)
|
|
{
|
|
req->ki_filp = fget(iocb->aio_fildes);
|
|
if (unlikely(!req->ki_filp))
|
|
return -EBADF;
|
|
|
|
if (iocb->aio_flags & IOCB_FLAG_RESFD) {
|
|
struct eventfd_ctx *eventfd;
|
|
/*
|
|
* If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
|
|
* instance of the file* now. The file descriptor must be
|
|
* an eventfd() fd, and will be signaled for each completed
|
|
* event using the eventfd_signal() function.
|
|
*/
|
|
eventfd = eventfd_ctx_fdget(iocb->aio_resfd);
|
|
if (IS_ERR(eventfd))
|
|
return PTR_ERR(eventfd);
|
|
|
|
req->ki_eventfd = eventfd;
|
|
}
|
|
|
|
if (unlikely(put_user(KIOCB_KEY, &user_iocb->aio_key))) {
|
|
pr_debug("EFAULT: aio_key\n");
|
|
return -EFAULT;
|
|
}
|
|
|
|
req->ki_res.obj = (u64)(unsigned long)user_iocb;
|
|
req->ki_res.data = iocb->aio_data;
|
|
req->ki_res.res = 0;
|
|
req->ki_res.res2 = 0;
|
|
|
|
switch (iocb->aio_lio_opcode) {
|
|
case IOCB_CMD_PREAD:
|
|
return aio_read(&req->rw, iocb, false, compat);
|
|
case IOCB_CMD_PWRITE:
|
|
return aio_write(&req->rw, iocb, false, compat);
|
|
case IOCB_CMD_PREADV:
|
|
return aio_read(&req->rw, iocb, true, compat);
|
|
case IOCB_CMD_PWRITEV:
|
|
return aio_write(&req->rw, iocb, true, compat);
|
|
case IOCB_CMD_FSYNC:
|
|
return aio_fsync(&req->fsync, iocb, false);
|
|
case IOCB_CMD_FDSYNC:
|
|
return aio_fsync(&req->fsync, iocb, true);
|
|
case IOCB_CMD_POLL:
|
|
return aio_poll(req, iocb);
|
|
default:
|
|
pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
|
|
bool compat)
|
|
{
|
|
struct aio_kiocb *req;
|
|
struct iocb iocb;
|
|
int err;
|
|
|
|
if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
|
|
return -EFAULT;
|
|
|
|
/* enforce forwards compatibility on users */
|
|
if (unlikely(iocb.aio_reserved2)) {
|
|
pr_debug("EINVAL: reserve field set\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* prevent overflows */
|
|
if (unlikely(
|
|
(iocb.aio_buf != (unsigned long)iocb.aio_buf) ||
|
|
(iocb.aio_nbytes != (size_t)iocb.aio_nbytes) ||
|
|
((ssize_t)iocb.aio_nbytes < 0)
|
|
)) {
|
|
pr_debug("EINVAL: overflow check\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
req = aio_get_req(ctx);
|
|
if (unlikely(!req))
|
|
return -EAGAIN;
|
|
|
|
err = __io_submit_one(ctx, &iocb, user_iocb, req, compat);
|
|
|
|
/* Done with the synchronous reference */
|
|
iocb_put(req);
|
|
|
|
/*
|
|
* If err is 0, we'd either done aio_complete() ourselves or have
|
|
* arranged for that to be done asynchronously. Anything non-zero
|
|
* means that we need to destroy req ourselves.
|
|
*/
|
|
if (unlikely(err)) {
|
|
iocb_destroy(req);
|
|
put_reqs_available(ctx, 1);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
/* sys_io_submit:
|
|
* Queue the nr iocbs pointed to by iocbpp for processing. Returns
|
|
* the number of iocbs queued. May return -EINVAL if the aio_context
|
|
* specified by ctx_id is invalid, if nr is < 0, if the iocb at
|
|
* *iocbpp[0] is not properly initialized, if the operation specified
|
|
* is invalid for the file descriptor in the iocb. May fail with
|
|
* -EFAULT if any of the data structures point to invalid data. May
|
|
* fail with -EBADF if the file descriptor specified in the first
|
|
* iocb is invalid. May fail with -EAGAIN if insufficient resources
|
|
* are available to queue any iocbs. Will return 0 if nr is 0. Will
|
|
* fail with -ENOSYS if not implemented.
|
|
*/
|
|
SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
|
|
struct iocb __user * __user *, iocbpp)
|
|
{
|
|
struct kioctx *ctx;
|
|
long ret = 0;
|
|
int i = 0;
|
|
struct blk_plug plug;
|
|
|
|
if (unlikely(nr < 0))
|
|
return -EINVAL;
|
|
|
|
ctx = lookup_ioctx(ctx_id);
|
|
if (unlikely(!ctx)) {
|
|
pr_debug("EINVAL: invalid context id\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (nr > ctx->nr_events)
|
|
nr = ctx->nr_events;
|
|
|
|
if (nr > AIO_PLUG_THRESHOLD)
|
|
blk_start_plug(&plug);
|
|
for (i = 0; i < nr; i++) {
|
|
struct iocb __user *user_iocb;
|
|
|
|
if (unlikely(get_user(user_iocb, iocbpp + i))) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
ret = io_submit_one(ctx, user_iocb, false);
|
|
if (ret)
|
|
break;
|
|
}
|
|
if (nr > AIO_PLUG_THRESHOLD)
|
|
blk_finish_plug(&plug);
|
|
|
|
percpu_ref_put(&ctx->users);
|
|
return i ? i : ret;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
|
|
int, nr, compat_uptr_t __user *, iocbpp)
|
|
{
|
|
struct kioctx *ctx;
|
|
long ret = 0;
|
|
int i = 0;
|
|
struct blk_plug plug;
|
|
|
|
if (unlikely(nr < 0))
|
|
return -EINVAL;
|
|
|
|
ctx = lookup_ioctx(ctx_id);
|
|
if (unlikely(!ctx)) {
|
|
pr_debug("EINVAL: invalid context id\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (nr > ctx->nr_events)
|
|
nr = ctx->nr_events;
|
|
|
|
if (nr > AIO_PLUG_THRESHOLD)
|
|
blk_start_plug(&plug);
|
|
for (i = 0; i < nr; i++) {
|
|
compat_uptr_t user_iocb;
|
|
|
|
if (unlikely(get_user(user_iocb, iocbpp + i))) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
ret = io_submit_one(ctx, compat_ptr(user_iocb), true);
|
|
if (ret)
|
|
break;
|
|
}
|
|
if (nr > AIO_PLUG_THRESHOLD)
|
|
blk_finish_plug(&plug);
|
|
|
|
percpu_ref_put(&ctx->users);
|
|
return i ? i : ret;
|
|
}
|
|
#endif
|
|
|
|
/* sys_io_cancel:
|
|
* Attempts to cancel an iocb previously passed to io_submit. If
|
|
* the operation is successfully cancelled, the resulting event is
|
|
* copied into the memory pointed to by result without being placed
|
|
* into the completion queue and 0 is returned. May fail with
|
|
* -EFAULT if any of the data structures pointed to are invalid.
|
|
* May fail with -EINVAL if aio_context specified by ctx_id is
|
|
* invalid. May fail with -EAGAIN if the iocb specified was not
|
|
* cancelled. Will fail with -ENOSYS if not implemented.
|
|
*/
|
|
SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
|
|
struct io_event __user *, result)
|
|
{
|
|
struct kioctx *ctx;
|
|
struct aio_kiocb *kiocb;
|
|
int ret = -EINVAL;
|
|
u32 key;
|
|
u64 obj = (u64)(unsigned long)iocb;
|
|
|
|
if (unlikely(get_user(key, &iocb->aio_key)))
|
|
return -EFAULT;
|
|
if (unlikely(key != KIOCB_KEY))
|
|
return -EINVAL;
|
|
|
|
ctx = lookup_ioctx(ctx_id);
|
|
if (unlikely(!ctx))
|
|
return -EINVAL;
|
|
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
/* TODO: use a hash or array, this sucks. */
|
|
list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
|
|
if (kiocb->ki_res.obj == obj) {
|
|
ret = kiocb->ki_cancel(&kiocb->rw);
|
|
list_del_init(&kiocb->ki_list);
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
if (!ret) {
|
|
/*
|
|
* The result argument is no longer used - the io_event is
|
|
* always delivered via the ring buffer. -EINPROGRESS indicates
|
|
* cancellation is progress:
|
|
*/
|
|
ret = -EINPROGRESS;
|
|
}
|
|
|
|
percpu_ref_put(&ctx->users);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static long do_io_getevents(aio_context_t ctx_id,
|
|
long min_nr,
|
|
long nr,
|
|
struct io_event __user *events,
|
|
struct timespec64 *ts)
|
|
{
|
|
ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX;
|
|
struct kioctx *ioctx = lookup_ioctx(ctx_id);
|
|
long ret = -EINVAL;
|
|
|
|
if (likely(ioctx)) {
|
|
if (likely(min_nr <= nr && min_nr >= 0))
|
|
ret = read_events(ioctx, min_nr, nr, events, until);
|
|
percpu_ref_put(&ioctx->users);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* io_getevents:
|
|
* Attempts to read at least min_nr events and up to nr events from
|
|
* the completion queue for the aio_context specified by ctx_id. If
|
|
* it succeeds, the number of read events is returned. May fail with
|
|
* -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
|
|
* out of range, if timeout is out of range. May fail with -EFAULT
|
|
* if any of the memory specified is invalid. May return 0 or
|
|
* < min_nr if the timeout specified by timeout has elapsed
|
|
* before sufficient events are available, where timeout == NULL
|
|
* specifies an infinite timeout. Note that the timeout pointed to by
|
|
* timeout is relative. Will fail with -ENOSYS if not implemented.
|
|
*/
|
|
#ifdef CONFIG_64BIT
|
|
|
|
SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
|
|
long, min_nr,
|
|
long, nr,
|
|
struct io_event __user *, events,
|
|
struct __kernel_timespec __user *, timeout)
|
|
{
|
|
struct timespec64 ts;
|
|
int ret;
|
|
|
|
if (timeout && unlikely(get_timespec64(&ts, timeout)))
|
|
return -EFAULT;
|
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
|
|
if (!ret && signal_pending(current))
|
|
ret = -EINTR;
|
|
return ret;
|
|
}
|
|
|
|
#endif
|
|
|
|
struct __aio_sigset {
|
|
const sigset_t __user *sigmask;
|
|
size_t sigsetsize;
|
|
};
|
|
|
|
SYSCALL_DEFINE6(io_pgetevents,
|
|
aio_context_t, ctx_id,
|
|
long, min_nr,
|
|
long, nr,
|
|
struct io_event __user *, events,
|
|
struct __kernel_timespec __user *, timeout,
|
|
const struct __aio_sigset __user *, usig)
|
|
{
|
|
struct __aio_sigset ksig = { NULL, };
|
|
struct timespec64 ts;
|
|
bool interrupted;
|
|
int ret;
|
|
|
|
if (timeout && unlikely(get_timespec64(&ts, timeout)))
|
|
return -EFAULT;
|
|
|
|
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
|
|
return -EFAULT;
|
|
|
|
ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
|
|
|
|
interrupted = signal_pending(current);
|
|
restore_saved_sigmask_unless(interrupted);
|
|
if (interrupted && !ret)
|
|
ret = -ERESTARTNOHAND;
|
|
|
|
return ret;
|
|
}
|
|
|
|
#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
|
|
|
|
SYSCALL_DEFINE6(io_pgetevents_time32,
|
|
aio_context_t, ctx_id,
|
|
long, min_nr,
|
|
long, nr,
|
|
struct io_event __user *, events,
|
|
struct old_timespec32 __user *, timeout,
|
|
const struct __aio_sigset __user *, usig)
|
|
{
|
|
struct __aio_sigset ksig = { NULL, };
|
|
struct timespec64 ts;
|
|
bool interrupted;
|
|
int ret;
|
|
|
|
if (timeout && unlikely(get_old_timespec32(&ts, timeout)))
|
|
return -EFAULT;
|
|
|
|
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
|
|
return -EFAULT;
|
|
|
|
|
|
ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
|
|
|
|
interrupted = signal_pending(current);
|
|
restore_saved_sigmask_unless(interrupted);
|
|
if (interrupted && !ret)
|
|
ret = -ERESTARTNOHAND;
|
|
|
|
return ret;
|
|
}
|
|
|
|
#endif
|
|
|
|
#if defined(CONFIG_COMPAT_32BIT_TIME)
|
|
|
|
SYSCALL_DEFINE5(io_getevents_time32, __u32, ctx_id,
|
|
__s32, min_nr,
|
|
__s32, nr,
|
|
struct io_event __user *, events,
|
|
struct old_timespec32 __user *, timeout)
|
|
{
|
|
struct timespec64 t;
|
|
int ret;
|
|
|
|
if (timeout && get_old_timespec32(&t, timeout))
|
|
return -EFAULT;
|
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
|
|
if (!ret && signal_pending(current))
|
|
ret = -EINTR;
|
|
return ret;
|
|
}
|
|
|
|
#endif
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
|
|
struct __compat_aio_sigset {
|
|
compat_uptr_t sigmask;
|
|
compat_size_t sigsetsize;
|
|
};
|
|
|
|
#if defined(CONFIG_COMPAT_32BIT_TIME)
|
|
|
|
COMPAT_SYSCALL_DEFINE6(io_pgetevents,
|
|
compat_aio_context_t, ctx_id,
|
|
compat_long_t, min_nr,
|
|
compat_long_t, nr,
|
|
struct io_event __user *, events,
|
|
struct old_timespec32 __user *, timeout,
|
|
const struct __compat_aio_sigset __user *, usig)
|
|
{
|
|
struct __compat_aio_sigset ksig = { 0, };
|
|
struct timespec64 t;
|
|
bool interrupted;
|
|
int ret;
|
|
|
|
if (timeout && get_old_timespec32(&t, timeout))
|
|
return -EFAULT;
|
|
|
|
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
|
|
return -EFAULT;
|
|
|
|
ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
|
|
|
|
interrupted = signal_pending(current);
|
|
restore_saved_sigmask_unless(interrupted);
|
|
if (interrupted && !ret)
|
|
ret = -ERESTARTNOHAND;
|
|
|
|
return ret;
|
|
}
|
|
|
|
#endif
|
|
|
|
COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,
|
|
compat_aio_context_t, ctx_id,
|
|
compat_long_t, min_nr,
|
|
compat_long_t, nr,
|
|
struct io_event __user *, events,
|
|
struct __kernel_timespec __user *, timeout,
|
|
const struct __compat_aio_sigset __user *, usig)
|
|
{
|
|
struct __compat_aio_sigset ksig = { 0, };
|
|
struct timespec64 t;
|
|
bool interrupted;
|
|
int ret;
|
|
|
|
if (timeout && get_timespec64(&t, timeout))
|
|
return -EFAULT;
|
|
|
|
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
|
|
return -EFAULT;
|
|
|
|
ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
|
|
|
|
interrupted = signal_pending(current);
|
|
restore_saved_sigmask_unless(interrupted);
|
|
if (interrupted && !ret)
|
|
ret = -ERESTARTNOHAND;
|
|
|
|
return ret;
|
|
}
|
|
#endif
|