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new helper: iov_iter_get_pages_alloc()

Browse Source 
same as iov_iter_get_pages(), except that pages array is allocated
(kmalloc if possible, vmalloc if that fails) and left for caller to
free.  Lustre and NFS ->direct_IO() switched to it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-03-21 04:58:33 -04:00
parent f67da30c1d
commit 91f79c43d1
4 changed files with 168 additions and 258 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

96
drivers/staging/lustre/lustre/llite/rw26.c
View File

@ -218,14 +218,11 @@ static void ll_free_user_pages(struct page **pages, int npages, int do_dirty)
int i;
for (i = 0; i < npages; i++) {
if (pages[i] == NULL)
break;
if (do_dirty)
set_page_dirty_lock(pages[i]);
page_cache_release(pages[i]);
}
OBD_FREE_LARGE(pages, npages * sizeof(*pages));
kvfree(pages);
}
ssize_t ll_direct_rw_pages(const struct lu_env *env, struct cl_io *io,
@ -370,10 +367,9 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct ccc_object *obj = cl_inode2ccc(inode);
long count = iov_iter_count(iter);
long tot_bytes = 0, result = 0;
ssize_t count = iov_iter_count(iter);
ssize_t tot_bytes = 0, result = 0;
struct ll_inode_info *lli = ll_i2info(inode);
unsigned long seg = 0;
long size = MAX_DIO_SIZE;
int refcheck;
@ -407,63 +403,49 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
mutex_lock(&inode->i_mutex);
LASSERT(obj->cob_transient_pages == 0);
for (seg = 0; seg < iter->nr_segs; seg++) {
long iov_left = iter->iov[seg].iov_len;
unsigned long user_addr = (unsigned long)iter->iov[seg].iov_base;
while (iov_iter_count(iter)) {
struct page **pages;
size_t offs;
count = min_t(size_t, iov_iter_count(iter), size);
if (rw == READ) {
if (file_offset >= i_size_read(inode))
break;
if (file_offset + iov_left > i_size_read(inode))
iov_left = i_size_read(inode) - file_offset;
if (file_offset + count > i_size_read(inode))
count = i_size_read(inode) - file_offset;
}
while (iov_left > 0) {
struct page **pages;
int page_count, max_pages = 0;
long bytes;
bytes = min(size, iov_left);
page_count = ll_get_user_pages(rw, user_addr, bytes,
&pages, &max_pages);
if (likely(page_count > 0)) {
if (unlikely(page_count < max_pages))
bytes = page_count << PAGE_CACHE_SHIFT;
result = ll_direct_IO_26_seg(env, io, rw, inode,
file->f_mapping,
bytes, file_offset,
pages, page_count);
ll_free_user_pages(pages, max_pages, rw==READ);
} else if (page_count == 0) {
GOTO(out, result = -EFAULT);
} else {
result = page_count;
}
if (unlikely(result <= 0)) {
/* If we can't allocate a large enough buffer
* for the request, shrink it to a smaller
* PAGE_SIZE multiple and try again.
* We should always be able to kmalloc for a
* page worth of page pointers = 4MB on i386. */
if (result == -ENOMEM &&
size > (PAGE_CACHE_SIZE / sizeof(*pages)) *
PAGE_CACHE_SIZE) {
size = ((((size / 2) - 1) |
~CFS_PAGE_MASK) + 1) &
CFS_PAGE_MASK;
CDEBUG(D_VFSTRACE,"DIO size now %lu\n",
size);
continue;
}
GOTO(out, result);
}
tot_bytes += result;
file_offset += result;
iov_left -= result;
user_addr += result;
result = iov_iter_get_pages_alloc(iter, &pages, count, &offs);
if (likely(result > 0)) {
int n = (result + offs + PAGE_SIZE - 1) / PAGE_SIZE;
result = ll_direct_IO_26_seg(env, io, rw, inode,
file->f_mapping,
result, file_offset,
pages, n);
ll_free_user_pages(pages, n, rw==READ);
}
if (unlikely(result <= 0)) {
/* If we can't allocate a large enough buffer
* for the request, shrink it to a smaller
* PAGE_SIZE multiple and try again.
* We should always be able to kmalloc for a
* page worth of page pointers = 4MB on i386. */
if (result == -ENOMEM &&
size > (PAGE_CACHE_SIZE / sizeof(*pages)) *
PAGE_CACHE_SIZE) {
size = ((((size / 2) - 1) |
~CFS_PAGE_MASK) + 1) &
CFS_PAGE_MASK;
CDEBUG(D_VFSTRACE,"DIO size now %lu\n",
size);
continue;
}
GOTO(out, result);
}
iov_iter_advance(iter, result);
tot_bytes += result;
file_offset += result;
}
out:
LASSERT(obj->cob_transient_pages == 0);

288
fs/nfs/direct.c
View File

@ -322,60 +322,37 @@ static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = {
* handled automatically by nfs_direct_read_result(). Otherwise, if
* no requests have been sent, just return an error.
*/
static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *desc,
const struct iovec *iov,
loff_t pos, bool uio)
static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
struct iov_iter *iter,
loff_t pos)
{
struct nfs_direct_req *dreq = desc->pg_dreq;
struct nfs_open_context *ctx = dreq->ctx;
struct inode *inode = ctx->dentry->d_inode;
unsigned long user_addr = (unsigned long)iov->iov_base;
size_t count = iov->iov_len;
size_t rsize = NFS_SERVER(inode)->rsize;
unsigned int pgbase;
int result;
ssize_t started = 0;
struct page **pagevec = NULL;
unsigned int npages;
struct nfs_pageio_descriptor desc;
struct inode *inode = dreq->inode;
ssize_t result = -EINVAL;
size_t requested_bytes = 0;
size_t rsize = max_t(size_t, NFS_SERVER(inode)->rsize, PAGE_SIZE);
do {
NFS_PROTO(dreq->inode)->read_pageio_init(&desc, dreq->inode,
&nfs_direct_read_completion_ops);
get_dreq(dreq);
desc.pg_dreq = dreq;
atomic_inc(&inode->i_dio_count);
while (iov_iter_count(iter)) {
struct page **pagevec;
size_t bytes;
int i;
size_t pgbase;
unsigned npages, i;
pgbase = user_addr & ~PAGE_MASK;
bytes = min(max_t(size_t, rsize, PAGE_SIZE), count);
result = -ENOMEM;
npages = nfs_page_array_len(pgbase, bytes);
if (!pagevec)
pagevec = kmalloc(npages * sizeof(struct page *),
GFP_KERNEL);
if (!pagevec)
result = iov_iter_get_pages_alloc(iter, &pagevec,
rsize, &pgbase);
if (result < 0)
break;
if (uio) {
down_read(&current->mm->mmap_sem);
result = get_user_pages(current, current->mm, user_addr,
npages, 1, 0, pagevec, NULL);
up_read(&current->mm->mmap_sem);
if (result < 0)
break;
} else {
WARN_ON(npages != 1);
result = get_kernel_page(user_addr, 1, pagevec);
if (WARN_ON(result != 1))
break;
}
if ((unsigned)result < npages) {
bytes = result * PAGE_SIZE;
if (bytes <= pgbase) {
nfs_direct_release_pages(pagevec, result);
break;
}
bytes -= pgbase;
npages = result;
}
bytes = result;
iov_iter_advance(iter, bytes);
npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE;
for (i = 0; i < npages; i++) {
struct nfs_page *req;
unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase);
@ -389,55 +366,21 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *de
}
req->wb_index = pos >> PAGE_SHIFT;
req->wb_offset = pos & ~PAGE_MASK;
if (!nfs_pageio_add_request(desc, req)) {
result = desc->pg_error;
if (!nfs_pageio_add_request(&desc, req)) {
result = desc.pg_error;
nfs_release_request(req);
break;
}
pgbase = 0;
bytes -= req_len;
started += req_len;
user_addr += req_len;
requested_bytes += req_len;
pos += req_len;
count -= req_len;
dreq->bytes_left -= req_len;
}
/* The nfs_page now hold references to these pages */
nfs_direct_release_pages(pagevec, npages);
} while (count != 0 && result >= 0);
kfree(pagevec);
if (started)
return started;
return result < 0 ? (ssize_t) result : -EFAULT;
}
static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
struct iov_iter *iter,
loff_t pos, bool uio)
{
struct nfs_pageio_descriptor desc;
struct inode *inode = dreq->inode;
ssize_t result = -EINVAL;
size_t requested_bytes = 0;
unsigned long seg;
NFS_PROTO(dreq->inode)->read_pageio_init(&desc, dreq->inode,
&nfs_direct_read_completion_ops);
get_dreq(dreq);
desc.pg_dreq = dreq;
atomic_inc(&inode->i_dio_count);
for (seg = 0; seg < iter->nr_segs; seg++) {
const struct iovec *vec = &iter->iov[seg];
result = nfs_direct_read_schedule_segment(&desc, vec, pos, uio);
kvfree(pagevec);
if (result < 0)
break;
requested_bytes += result;
if ((size_t)result < vec->iov_len)
break;
pos += vec->iov_len;
}
nfs_pageio_complete(&desc);
@ -521,7 +464,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
dreq->iocb = iocb;
NFS_I(inode)->read_io += count;
result = nfs_direct_read_schedule_iovec(dreq, iter, pos, uio);
result = nfs_direct_read_schedule_iovec(dreq, iter, pos);
mutex_unlock(&inode->i_mutex);
@ -677,109 +620,6 @@ static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode
}
#endif
/*
* NB: Return the value of the first error return code. Subsequent
* errors after the first one are ignored.
*/
/*
* For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE
* operation. If nfs_writedata_alloc() or get_user_pages() fails,
* bail and stop sending more writes. Write length accounting is
* handled automatically by nfs_direct_write_result(). Otherwise, if
* no requests have been sent, just return an error.
*/
static ssize_t nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor *desc,
const struct iovec *iov,
loff_t pos, bool uio)
{
struct nfs_direct_req *dreq = desc->pg_dreq;
struct nfs_open_context *ctx = dreq->ctx;
struct inode *inode = ctx->dentry->d_inode;
unsigned long user_addr = (unsigned long)iov->iov_base;
size_t count = iov->iov_len;
size_t wsize = NFS_SERVER(inode)->wsize;
unsigned int pgbase;
int result;
ssize_t started = 0;
struct page **pagevec = NULL;
unsigned int npages;
do {
size_t bytes;
int i;
pgbase = user_addr & ~PAGE_MASK;
bytes = min(max_t(size_t, wsize, PAGE_SIZE), count);
result = -ENOMEM;
npages = nfs_page_array_len(pgbase, bytes);
if (!pagevec)
pagevec = kmalloc(npages * sizeof(struct page *), GFP_KERNEL);
if (!pagevec)
break;
if (uio) {
down_read(&current->mm->mmap_sem);
result = get_user_pages(current, current->mm, user_addr,
npages, 0, 0, pagevec, NULL);
up_read(&current->mm->mmap_sem);
if (result < 0)
break;
} else {
WARN_ON(npages != 1);
result = get_kernel_page(user_addr, 0, pagevec);
if (WARN_ON(result != 1))
break;
}
if ((unsigned)result < npages) {
bytes = result * PAGE_SIZE;
if (bytes <= pgbase) {
nfs_direct_release_pages(pagevec, result);
break;
}
bytes -= pgbase;
npages = result;
}
for (i = 0; i < npages; i++) {
struct nfs_page *req;
unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase);
req = nfs_create_request(dreq->ctx, dreq->inode,
pagevec[i],
pgbase, req_len);
if (IS_ERR(req)) {
result = PTR_ERR(req);
break;
}
nfs_lock_request(req);
req->wb_index = pos >> PAGE_SHIFT;
req->wb_offset = pos & ~PAGE_MASK;
if (!nfs_pageio_add_request(desc, req)) {
result = desc->pg_error;
nfs_unlock_and_release_request(req);
break;
}
pgbase = 0;
bytes -= req_len;
started += req_len;
user_addr += req_len;
pos += req_len;
count -= req_len;
dreq->bytes_left -= req_len;
}
/* The nfs_page now hold references to these pages */
nfs_direct_release_pages(pagevec, npages);
} while (count != 0 && result >= 0);
kfree(pagevec);
if (started)
return started;
return result < 0 ? (ssize_t) result : -EFAULT;
}
static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)
{
struct nfs_direct_req *dreq = hdr->dreq;
@ -859,15 +699,27 @@ static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = {
.completion = nfs_direct_write_completion,
};
/*
* NB: Return the value of the first error return code. Subsequent
* errors after the first one are ignored.
*/
/*
* For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE
* operation. If nfs_writedata_alloc() or get_user_pages() fails,
* bail and stop sending more writes. Write length accounting is
* handled automatically by nfs_direct_write_result(). Otherwise, if
* no requests have been sent, just return an error.
*/
static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
struct iov_iter *iter,
loff_t pos, bool uio)
loff_t pos)
{
struct nfs_pageio_descriptor desc;
struct inode *inode = dreq->inode;
ssize_t result = 0;
size_t requested_bytes = 0;
unsigned long seg;
size_t wsize = max_t(size_t, NFS_SERVER(inode)->wsize, PAGE_SIZE);
NFS_PROTO(inode)->write_pageio_init(&desc, inode, FLUSH_COND_STABLE,
&nfs_direct_write_completion_ops);
@ -875,16 +727,50 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
get_dreq(dreq);
atomic_inc(&inode->i_dio_count);
NFS_I(dreq->inode)->write_io += iov_iter_count(iter);
for (seg = 0; seg < iter->nr_segs; seg++) {
const struct iovec *vec = &iter->iov[seg];
result = nfs_direct_write_schedule_segment(&desc, vec, pos, uio);
NFS_I(inode)->write_io += iov_iter_count(iter);
while (iov_iter_count(iter)) {
struct page **pagevec;
size_t bytes;
size_t pgbase;
unsigned npages, i;
result = iov_iter_get_pages_alloc(iter, &pagevec,
wsize, &pgbase);
if (result < 0)
break;
requested_bytes += result;
if ((size_t)result < vec->iov_len)
bytes = result;
iov_iter_advance(iter, bytes);
npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE;
for (i = 0; i < npages; i++) {
struct nfs_page *req;
unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase);
req = nfs_create_request(dreq->ctx, inode,
pagevec[i],
pgbase, req_len);
if (IS_ERR(req)) {
result = PTR_ERR(req);
break;
}
nfs_lock_request(req);
req->wb_index = pos >> PAGE_SHIFT;
req->wb_offset = pos & ~PAGE_MASK;
if (!nfs_pageio_add_request(&desc, req)) {
result = desc.pg_error;
nfs_unlock_and_release_request(req);
break;
}
pgbase = 0;
bytes -= req_len;
requested_bytes += req_len;
pos += req_len;
dreq->bytes_left -= req_len;
}
nfs_direct_release_pages(pagevec, npages);
kvfree(pagevec);
if (result < 0)
break;
pos += vec->iov_len;
}
nfs_pageio_complete(&desc);
@ -985,7 +871,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter,
if (!is_sync_kiocb(iocb))
dreq->iocb = iocb;
result = nfs_direct_write_schedule_iovec(dreq, iter, pos, uio);
result = nfs_direct_write_schedule_iovec(dreq, iter, pos);
if (mapping->nrpages) {
invalidate_inode_pages2_range(mapping,

2
include/linux/uio.h
View File

@ -73,6 +73,8 @@ void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
unsigned long nr_segs, size_t count);
ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
size_t maxsize, size_t *start);
ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
size_t maxsize, size_t *start);
int iov_iter_npages(const struct iov_iter *i, int maxpages);
static inline size_t iov_iter_count(struct iov_iter *i)

40
mm/iov_iter.c
View File

@ -1,6 +1,8 @@
#include <linux/export.h>
#include <linux/uio.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
@ -263,6 +265,44 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
}
EXPORT_SYMBOL(iov_iter_get_pages);
ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
struct page ***pages, size_t maxsize,
size_t *start)
{
size_t offset = i->iov_offset;
const struct iovec *iov = i->iov;
size_t len;
unsigned long addr;
void *p;
int n;
int res;
len = iov->iov_len - offset;
if (len > i->count)
len = i->count;
if (len > maxsize)
len = maxsize;
addr = (unsigned long)iov->iov_base + offset;
len += *start = addr & (PAGE_SIZE - 1);
addr &= ~(PAGE_SIZE - 1);
n = (len + PAGE_SIZE - 1) / PAGE_SIZE;
p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
if (!p)
p = vmalloc(n * sizeof(struct page *));
if (!p)
return -ENOMEM;
res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
if (unlikely(res < 0)) {
kvfree(p);
return res;
}
*pages = p;
return (res == n ? len : res * PAGE_SIZE) - *start;
}
EXPORT_SYMBOL(iov_iter_get_pages_alloc);
int iov_iter_npages(const struct iov_iter *i, int maxpages)
{
size_t offset = i->iov_offset;