mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-11 21:38:32 +08:00
Merge branch 'work.aio' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs aio updates from Al Viro: "Christoph's aio poll, saner this time around. This time it's pretty much local to fs/aio.c. Hopefully race-free..." * 'work.aio' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: aio: allow direct aio poll comletions for keyed wakeups aio: implement IOCB_CMD_POLL aio: add a iocb refcount timerfd: add support for keyed wakeups
This commit is contained in:
commit
f2be269897
208
fs/aio.c
208
fs/aio.c
@ -5,6 +5,7 @@
|
||||
* 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.
|
||||
*/
|
||||
@ -18,6 +19,7 @@
|
||||
#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>
|
||||
@ -164,10 +166,21 @@ struct fsync_iocb {
|
||||
bool datasync;
|
||||
};
|
||||
|
||||
struct poll_iocb {
|
||||
struct file *file;
|
||||
struct wait_queue_head *head;
|
||||
__poll_t events;
|
||||
bool woken;
|
||||
bool cancelled;
|
||||
struct wait_queue_entry wait;
|
||||
struct work_struct work;
|
||||
};
|
||||
|
||||
struct aio_kiocb {
|
||||
union {
|
||||
struct kiocb rw;
|
||||
struct fsync_iocb fsync;
|
||||
struct poll_iocb poll;
|
||||
};
|
||||
|
||||
struct kioctx *ki_ctx;
|
||||
@ -178,6 +191,7 @@ struct aio_kiocb {
|
||||
|
||||
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,
|
||||
@ -999,6 +1013,7 @@ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
|
||||
|
||||
percpu_ref_get(&ctx->reqs);
|
||||
INIT_LIST_HEAD(&req->ki_list);
|
||||
refcount_set(&req->ki_refcnt, 0);
|
||||
req->ki_ctx = ctx;
|
||||
return req;
|
||||
out_put:
|
||||
@ -1033,6 +1048,15 @@ out:
|
||||
return ret;
|
||||
}
|
||||
|
||||
static inline void iocb_put(struct aio_kiocb *iocb)
|
||||
{
|
||||
if (refcount_read(&iocb->ki_refcnt) == 0 ||
|
||||
refcount_dec_and_test(&iocb->ki_refcnt)) {
|
||||
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.
|
||||
*/
|
||||
@ -1102,8 +1126,6 @@ static void aio_complete(struct aio_kiocb *iocb, long res, long res2)
|
||||
eventfd_ctx_put(iocb->ki_eventfd);
|
||||
}
|
||||
|
||||
kmem_cache_free(kiocb_cachep, iocb);
|
||||
|
||||
/*
|
||||
* We have to order our ring_info tail store above and test
|
||||
* of the wait list below outside the wait lock. This is
|
||||
@ -1114,8 +1136,7 @@ static void aio_complete(struct aio_kiocb *iocb, long res, long res2)
|
||||
|
||||
if (waitqueue_active(&ctx->wait))
|
||||
wake_up(&ctx->wait);
|
||||
|
||||
percpu_ref_put(&ctx->reqs);
|
||||
iocb_put(iocb);
|
||||
}
|
||||
|
||||
/* aio_read_events_ring
|
||||
@ -1576,6 +1597,182 @@ static int aio_fsync(struct fsync_iocb *req, struct iocb *iocb, bool datasync)
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline void aio_poll_complete(struct aio_kiocb *iocb, __poll_t mask)
|
||||
{
|
||||
struct file *file = iocb->poll.file;
|
||||
|
||||
aio_complete(iocb, mangle_poll(mask), 0);
|
||||
fput(file);
|
||||
}
|
||||
|
||||
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);
|
||||
spin_unlock_irq(&ctx->ctx_lock);
|
||||
|
||||
aio_poll_complete(iocb, mask);
|
||||
}
|
||||
|
||||
/* 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);
|
||||
|
||||
req->woken = true;
|
||||
|
||||
/* for instances that support it check for an event match first: */
|
||||
if (mask) {
|
||||
if (!(mask & req->events))
|
||||
return 0;
|
||||
|
||||
/* try to complete the iocb inline if we can: */
|
||||
if (spin_trylock(&iocb->ki_ctx->ctx_lock)) {
|
||||
list_del(&iocb->ki_list);
|
||||
spin_unlock(&iocb->ki_ctx->ctx_lock);
|
||||
|
||||
list_del_init(&req->wait.entry);
|
||||
aio_poll_complete(iocb, mask);
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
|
||||
list_del_init(&req->wait.entry);
|
||||
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 ssize_t aio_poll(struct aio_kiocb *aiocb, struct iocb *iocb)
|
||||
{
|
||||
struct kioctx *ctx = aiocb->ki_ctx;
|
||||
struct poll_iocb *req = &aiocb->poll;
|
||||
struct aio_poll_table apt;
|
||||
__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->file = fget(iocb->aio_fildes);
|
||||
if (unlikely(!req->file))
|
||||
return -EBADF;
|
||||
|
||||
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);
|
||||
|
||||
/* one for removal from waitqueue, one for this function */
|
||||
refcount_set(&aiocb->ki_refcnt, 2);
|
||||
|
||||
mask = vfs_poll(req->file, &apt.pt) & req->events;
|
||||
if (unlikely(!req->head)) {
|
||||
/* we did not manage to set up a waitqueue, done */
|
||||
goto out;
|
||||
}
|
||||
|
||||
spin_lock_irq(&ctx->ctx_lock);
|
||||
spin_lock(&req->head->lock);
|
||||
if (req->woken) {
|
||||
/* wake_up context handles the rest */
|
||||
mask = 0;
|
||||
apt.error = 0;
|
||||
} else if (mask || apt.error) {
|
||||
/* if we get an error or a mask we are done */
|
||||
WARN_ON_ONCE(list_empty(&req->wait.entry));
|
||||
list_del_init(&req->wait.entry);
|
||||
} else {
|
||||
/* 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);
|
||||
spin_unlock_irq(&ctx->ctx_lock);
|
||||
|
||||
out:
|
||||
if (unlikely(apt.error)) {
|
||||
fput(req->file);
|
||||
return apt.error;
|
||||
}
|
||||
|
||||
if (mask)
|
||||
aio_poll_complete(aiocb, mask);
|
||||
iocb_put(aiocb);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
|
||||
bool compat)
|
||||
{
|
||||
@ -1649,6 +1846,9 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
|
||||
case IOCB_CMD_FDSYNC:
|
||||
ret = aio_fsync(&req->fsync, &iocb, true);
|
||||
break;
|
||||
case IOCB_CMD_POLL:
|
||||
ret = aio_poll(req, &iocb);
|
||||
break;
|
||||
default:
|
||||
pr_debug("invalid aio operation %d\n", iocb.aio_lio_opcode);
|
||||
ret = -EINVAL;
|
||||
|
@ -66,7 +66,7 @@ static void timerfd_triggered(struct timerfd_ctx *ctx)
|
||||
spin_lock_irqsave(&ctx->wqh.lock, flags);
|
||||
ctx->expired = 1;
|
||||
ctx->ticks++;
|
||||
wake_up_locked(&ctx->wqh);
|
||||
wake_up_locked_poll(&ctx->wqh, EPOLLIN);
|
||||
spin_unlock_irqrestore(&ctx->wqh.lock, flags);
|
||||
}
|
||||
|
||||
@ -107,7 +107,7 @@ void timerfd_clock_was_set(void)
|
||||
if (ctx->moffs != moffs) {
|
||||
ctx->moffs = KTIME_MAX;
|
||||
ctx->ticks++;
|
||||
wake_up_locked(&ctx->wqh);
|
||||
wake_up_locked_poll(&ctx->wqh, EPOLLIN);
|
||||
}
|
||||
spin_unlock_irqrestore(&ctx->wqh.lock, flags);
|
||||
}
|
||||
@ -345,7 +345,7 @@ static long timerfd_ioctl(struct file *file, unsigned int cmd, unsigned long arg
|
||||
spin_lock_irq(&ctx->wqh.lock);
|
||||
if (!timerfd_canceled(ctx)) {
|
||||
ctx->ticks = ticks;
|
||||
wake_up_locked(&ctx->wqh);
|
||||
wake_up_locked_poll(&ctx->wqh, EPOLLIN);
|
||||
} else
|
||||
ret = -ECANCELED;
|
||||
spin_unlock_irq(&ctx->wqh.lock);
|
||||
|
@ -38,10 +38,8 @@ enum {
|
||||
IOCB_CMD_PWRITE = 1,
|
||||
IOCB_CMD_FSYNC = 2,
|
||||
IOCB_CMD_FDSYNC = 3,
|
||||
/* These two are experimental.
|
||||
* IOCB_CMD_PREADX = 4,
|
||||
* IOCB_CMD_POLL = 5,
|
||||
*/
|
||||
/* 4 was the experimental IOCB_CMD_PREADX */
|
||||
IOCB_CMD_POLL = 5,
|
||||
IOCB_CMD_NOOP = 6,
|
||||
IOCB_CMD_PREADV = 7,
|
||||
IOCB_CMD_PWRITEV = 8,
|
||||
|
Loading…
Reference in New Issue
Block a user