// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2010 Red Hat, Inc.
* Copyright (c) 2016-2021 Christoph Hellwig.
*/
#include <linux/module.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/fscrypt.h>
#include <linux/pagemap.h>
#include <linux/iomap.h>
#include <linux/backing-dev.h>
#include <linux/uio.h>
#include <linux/task_io_accounting_ops.h>
#include "trace.h"
#include "../internal.h"
/*
* Private flags for iomap_dio, must not overlap with the public ones in
* iomap.h:
*/
#define IOMAP_DIO_CALLER_COMP (1U << 26)
#define IOMAP_DIO_INLINE_COMP (1U << 27)
#define IOMAP_DIO_WRITE_THROUGH (1U << 28)
#define IOMAP_DIO_NEED_SYNC (1U << 29)
#define IOMAP_DIO_WRITE (1U << 30)
#define IOMAP_DIO_DIRTY (1U << 31)
/*
* Used for sub block zeroing in iomap_dio_zero()
*/
#define IOMAP_ZERO_PAGE_SIZE (SZ_64K)
#define IOMAP_ZERO_PAGE_ORDER (get_order(IOMAP_ZERO_PAGE_SIZE))
static struct page *zero_page;
struct iomap_dio {
struct kiocb *iocb;
const struct iomap_dio_ops *dops;
loff_t i_size;
loff_t size;
atomic_t ref;
unsigned flags;
int error;
size_t done_before;
bool wait_for_completion;
union {
/* used during submission and for synchronous completion: */
struct {
struct iov_iter *iter;
struct task_struct *waiter;
} submit;
/* used for aio completion: */
struct {
struct work_struct work;
} aio;
};
};
static struct bio *iomap_dio_alloc_bio(const struct iomap_iter *iter,
struct iomap_dio *dio, unsigned short nr_vecs, blk_opf_t opf)
{
if (dio->dops && dio->dops->bio_set)
return bio_alloc_bioset(iter->iomap.bdev, nr_vecs, opf,
GFP_KERNEL, dio->dops->bio_set);
return bio_alloc(iter->iomap.bdev, nr_vecs, opf, GFP_KERNEL);
}
static void iomap_dio_submit_bio(const struct iomap_iter *iter,
struct iomap_dio *dio, struct bio *bio, loff_t pos)
{
struct kiocb *iocb = dio->iocb;
atomic_inc(&dio->ref);
/* Sync dio can't be polled reliably */
if ((iocb->ki_flags & IOCB_HIPRI) && !is_sync_kiocb(iocb)) {
bio_set_polled(bio, iocb);
WRITE_ONCE(iocb->private, bio);
}
if (dio->dops && dio->dops->submit_io)
dio->dops->submit_io(iter, bio, pos);
else
submit_bio(bio);
}
ssize_t iomap_dio_complete(struct iomap_dio *dio)
{
const struct iomap_dio_ops *dops = dio->dops;
struct kiocb *iocb = dio->iocb;
loff_t offset = iocb->ki_pos;
ssize_t ret = dio->error;
if (dops && dops->end_io)
ret = dops->end_io(iocb, dio->size, ret, dio->flags);
if (likely(!ret)) {
ret = dio->size;
/* check for short read */
if (offset + ret > dio->i_size &&
!(dio->flags & IOMAP_DIO_WRITE))
ret = dio->i_size - offset;
}
/*
* Try again to invalidate clean pages which might have been cached by
* non-direct readahead, or faulted in by get_user_pages() if the source
* of the write was an mmap'ed region of the file we're writing. Either
* one is a pretty crazy thing to do, so we don't support it 100%. If
* this invalidation fails, tough, the write still worked...
*
* And this page cache invalidation has to be after ->end_io(), as some
* filesystems convert unwritten extents to real allocations in
* ->end_io() when necessary, otherwise a racing buffer read would cache
* zeros from unwritten extents.
*/
if (!dio->error && dio->size && (dio->flags & IOMAP_DIO_WRITE))
kiocb_invalidate_post_direct_write(iocb, dio->size);
inode_dio_end(file_inode(iocb->ki_filp));
if (ret > 0) {
iocb->ki_pos += ret;
/*
* If this is a DSYNC write, make sure we push it to stable
* storage now that we've written data.
*/
if (dio->flags & IOMAP_DIO_NEED_SYNC)
ret = generic_write_sync(iocb, ret);
if (ret > 0)
ret += dio->done_before;
}
trace_iomap_dio_complete(iocb, dio->error, ret);
kfree(dio);
return ret;
}
EXPORT_SYMBOL_GPL(iomap_dio_complete);
static ssize_t iomap_dio_deferred_complete(void *data)
{
return iomap_dio_complete(data);
}
static void iomap_dio_complete_work(struct work_struct *work)
{
struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work);
struct kiocb *iocb = dio->iocb;
iocb->ki_complete(iocb, iomap_dio_complete(dio));
}
/*
* Set an error in the dio if none is set yet. We have to use cmpxchg
* as the submission context and the completion context(s) can race to
* update the error.
*/
static inline void iomap_dio_set_error(struct iomap_dio *dio, int ret)
{
cmpxchg(&dio->error, 0, ret);
}
void iomap_dio_bio_end_io(struct bio *bio)
{
struct iomap_dio *dio = bio->bi_private;
bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY);
struct kiocb *iocb = dio->iocb;
if (bio->bi_status)
iomap_dio_set_error(dio, blk_status_to_errno(bio->bi_status));
if (!atomic_dec_and_test(&dio->ref))
goto release_bio;
/*
* Synchronous dio, task itself will handle any completion work
* that needs after IO. All we need to do is wake the task.
*/
if (dio->wait_for_completion) {
struct task_struct *waiter = dio->submit.waiter;
WRITE_ONCE(dio->submit.waiter, NULL);
blk_wake_io_task(waiter);
goto release_bio;
}
/*
* Flagged with IOMAP_DIO_INLINE_COMP, we can complete it inline
*/
if (dio->flags & IOMAP_DIO_INLINE_COMP) {
WRITE_ONCE(iocb->private, NULL);
iomap_dio_complete_work(&dio->aio.work);
goto release_bio;
}
/*
* If this dio is flagged with IOMAP_DIO_CALLER_COMP, then schedule
* our completion that way to avoid an async punt to a workqueue.
*/
if (dio->flags & IOMAP_DIO_CALLER_COMP) {
/* only polled IO cares about private cleared */
iocb->private = dio;
iocb->dio_complete = iomap_dio_deferred_complete;
/*
* Invoke ->ki_complete() directly. We've assigned our
* dio_complete callback handler, and since the issuer set
* IOCB_DIO_CALLER_COMP, we know their ki_complete handler will
* notice ->dio_complete being set and will defer calling that
* handler until it can be done from a safe task context.
*
* Note that the 'res' being passed in here is not important
* for this case. The actual completion value of the request
* will be gotten from dio_complete when that is run by the
* issuer.
*/
iocb->ki_complete(iocb, 0);
goto release_bio;
}
/*
* Async DIO completion that requires filesystem level completion work
* gets punted to a work queue to complete as the operation may require
* more IO to be issued to finalise filesystem metadata changes or
* guarantee data integrity.
*/
INIT_WORK(&dio->aio.work, iomap_dio_complete_work);
queue_work(file_inode(iocb->ki_filp)->i_sb->s_dio_done_wq,
&dio->aio.work);
release_bio:
if (should_dirty) {
bio_check_pages_dirty(bio);
} else {
bio_release_pages(bio, false);
bio_put(bio);
}
}
EXPORT_SYMBOL_GPL(iomap_dio_bio_end_io);
static int iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio,
loff_t pos, unsigned len)
{
struct inode *inode = file_inode(dio->iocb->ki_filp);
struct bio *bio;
if (!len)
return 0;
/*
* Max block size supported is 64k
*/
if (WARN_ON_ONCE(len > IOMAP_ZERO_PAGE_SIZE))
return -EINVAL;
bio = iomap_dio_alloc_bio(iter, dio, 1, REQ_OP_WRITE | REQ_SYNC | REQ_IDLE);
fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits,
GFP_KERNEL);
bio->bi_iter.bi_sector = iomap_sector(&iter->iomap, pos);
bio->bi_private = dio;
bio->bi_end_io = iomap_dio_bio_end_io;
__bio_add_page(bio, zero_page, len, 0);
iomap_dio_submit_bio(iter, dio, bio, pos);
return 0;
}
/*
* Figure out the bio's operation flags from the dio request, the
* mapping, and whether or not we want FUA. Note that we can end up
* clearing the WRITE_THROUGH flag in the dio request.
*/
static inline blk_opf_t iomap_dio_bio_opflags(struct iomap_dio *dio,
const struct iomap *iomap, bool use_fua)
{
blk_opf_t opflags = REQ_SYNC | REQ_IDLE;
if (!(dio->flags & IOMAP_DIO_WRITE))
return REQ_OP_READ;
opflags |= REQ_OP_WRITE;
if (use_fua)
opflags |= REQ_FUA;
else
dio->flags &= ~IOMAP_DIO_WRITE_THROUGH;
return opflags;
}
static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter,
struct iomap_dio *dio)
{
const struct iomap *iomap = &iter->iomap;
struct inode *inode = iter->inode;
unsigned int fs_block_size = i_blocksize(inode), pad;
loff_t length = iomap_length(iter);
loff_t pos = iter->pos;
blk_opf_t bio_opf;
struct bio *bio;
bool need_zeroout = false;
bool use_fua = false;
int nr_pages, ret = 0;
size_t copied = 0;
size_t orig_count;
if ((pos | length) & (bdev_logical_block_size(iomap->bdev) - 1) ||
!bdev_iter_is_aligned(iomap->bdev, dio->submit.iter))
return -EINVAL;
if (iomap->type == IOMAP_UNWRITTEN) {
dio->flags |= IOMAP_DIO_UNWRITTEN;
need_zeroout = true;
}
if (iomap->flags & IOMAP_F_SHARED)
dio->flags |= IOMAP_DIO_COW;
if (iomap->flags & IOMAP_F_NEW) {
need_zeroout = true;
} else if (iomap->type == IOMAP_MAPPED) {
/*
* Use a FUA write if we need datasync semantics, this is a pure
* data IO that doesn't require any metadata updates (including
* after IO completion such as unwritten extent conversion) and
* the underlying device either supports FUA or doesn't have
* a volatile write cache. This allows us to avoid cache flushes
* on IO completion. If we can't use writethrough and need to
* sync, disable in-task completions as dio completion will
* need to call generic_write_sync() which will do a blocking
* fsync / cache flush call.
*/
if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) &&
(dio->flags & IOMAP_DIO_WRITE_THROUGH) &&
(bdev_fua(iomap->bdev) || !bdev_write_cache(iomap->bdev)))
use_fua = true;
else if (dio->flags & IOMAP_DIO_NEED_SYNC)
dio->flags &= ~IOMAP_DIO_CALLER_COMP;
}
/*
* Save the original count and trim the iter to just the extent we
* are operating on right now. The iter will be re-expanded once
* we are done.
*/
orig_count = iov_iter_count(dio->submit.iter);
iov_iter_truncate(dio->submit.iter, length);
if (!iov_iter_count(dio->submit.iter))
goto out;
/*
* We can only do deferred completion for pure overwrites that
* don't require additional IO at completion. This rules out
* writes that need zeroing or extent conversion, extend
* the file size, or issue journal IO or cache flushes
* during completion processing.
*/
if (need_zeroout ||
((dio->flags & IOMAP_DIO_NEED_SYNC) && !use_fua) ||
((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode)))
dio->flags &= ~IOMAP_DIO_CALLER_COMP;
/*
* The rules for polled IO completions follow the guidelines as the
* ones we set for inline and deferred completions. If none of those
* are available for this IO, clear the polled flag.
*/
if (!(dio->flags & (IOMAP_DIO_INLINE_COMP|IOMAP_DIO_CALLER_COMP)))
dio->iocb->ki_flags &= ~IOCB_HIPRI;
if (need_zeroout) {
/* zero out from the start of the block to the write offset */
pad = pos & (fs_block_size - 1);
ret = iomap_dio_zero(iter, dio, pos - pad, pad);
if (ret)
goto out;
}
/*
* Set the operation flags early so that bio_iov_iter_get_pages
* can set up the page vector appropriately for a ZONE_APPEND
* operation.
*/
bio_opf = iomap_dio_bio_opflags(dio, iomap, use_fua);
nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, BIO_MAX_VECS);
do {
size_t n;
if (dio->error) {
iov_iter_revert(dio->submit.iter, copied);
copied = ret = 0;
goto out;
}
bio = iomap_dio_alloc_bio(iter, dio, nr_pages, bio_opf);
fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits,
GFP_KERNEL);
bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
bio->bi_write_hint = inode->i_write_hint;
bio->bi_ioprio = dio->iocb->ki_ioprio;
bio->bi_private = dio;
bio->bi_end_io = iomap_dio_bio_end_io;
ret = bio_iov_iter_get_pages(bio, dio->submit.iter);
if (unlikely(ret)) {
/*
* We have to stop part way through an IO. We must fall
* through to the sub-block tail zeroing here, otherwise
* this short IO may expose stale data in the tail of
* the block we haven't written data to.
*/
bio_put(bio);
goto zero_tail;
}
n = bio->bi_iter.bi_size;
if (dio->flags & IOMAP_DIO_WRITE) {
task_io_account_write(n);
} else {
if (dio->flags & IOMAP_DIO_DIRTY)
bio_set_pages_dirty(bio);
}
dio->size += n;
copied += n;
nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter,
BIO_MAX_VECS);
/*
* We can only poll for single bio I/Os.
*/
if (nr_pages)
dio->iocb->ki_flags &= ~IOCB_HIPRI;
iomap_dio_submit_bio(iter, dio, bio, pos);
pos += n;
} while (nr_pages);
/*
* We need to zeroout the tail of a sub-block write if the extent type
* requires zeroing or the write extends beyond EOF. If we don't zero
* the block tail in the latter case, we can expose stale data via mmap
* reads of the EOF block.
*/
zero_tail:
if (need_zeroout ||
((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) {
/* zero out from the end of the write to the end of the block */
pad = pos & (fs_block_size - 1);
if (pad)
ret = iomap_dio_zero(iter, dio, pos,
fs_block_size - pad);
}
out:
/* Undo iter limitation to current extent */
iov_iter_reexpand(dio->submit.iter, orig_count - copied);
if (copied)
return copied;
return ret;
}
static loff_t iomap_dio_hole_iter(const struct iomap_iter *iter,
struct iomap_dio *dio)
{
loff_t length = iov_iter_zero(iomap_length(iter), dio->submit.iter);
dio->size += length;
if (!length)
return -EFAULT;
return length;
}
static loff_t iomap_dio_inline_iter(const struct iomap_iter *iomi,
struct iomap_dio *dio)
{
const struct iomap *iomap = &iomi->iomap;
struct iov_iter *iter = dio->submit.iter;
void *inline_data = iomap_inline_data(iomap, iomi->pos);
loff_t length = iomap_length(iomi);
loff_t pos = iomi->pos;
size_t copied;
if (WARN_ON_ONCE(!iomap_inline_data_valid(iomap)))
return -EIO;
if (dio->flags & IOMAP_DIO_WRITE) {
loff_t size = iomi->inode->i_size;
if (pos > size)
memset(iomap_inline_data(iomap, size), 0, pos - size);
copied = copy_from_iter(inline_data, length, iter);
if (copied) {
if (pos + copied > size)
i_size_write(iomi->inode, pos + copied);
mark_inode_dirty(iomi->inode);
}
} else {
copied = copy_to_iter(inline_data, length, iter);
}
dio->size += copied;
if (!copied)
return -EFAULT;
return copied;
}
static loff_t iomap_dio_iter(const struct iomap_iter *iter,
struct iomap_dio *dio)
{
switch (iter->iomap.type) {
case IOMAP_HOLE:
if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE))
return -EIO;
return iomap_dio_hole_iter(iter, dio);
case IOMAP_UNWRITTEN:
if (!(dio->flags & IOMAP_DIO_WRITE))
return iomap_dio_hole_iter(iter, dio);
return iomap_dio_bio_iter(iter, dio);
case IOMAP_MAPPED:
return iomap_dio_bio_iter(iter, dio);
case IOMAP_INLINE:
return iomap_dio_inline_iter(iter, dio);
case IOMAP_DELALLOC:
/*
* DIO is not serialised against mmap() access at all, and so
* if the page_mkwrite occurs between the writeback and the
* iomap_iter() call in the DIO path, then it will see the
* DELALLOC block that the page-mkwrite allocated.
*/
pr_warn_ratelimited("Direct I/O collision with buffered writes! File: %pD4 Comm: %.20s\n",
dio->iocb->ki_filp, current->comm);
return -EIO;
default:
WARN_ON_ONCE(1);
return -EIO;
}
}
/*
* iomap_dio_rw() always completes O_[D]SYNC writes regardless of whether the IO
* is being issued as AIO or not. This allows us to optimise pure data writes
* to use REQ_FUA rather than requiring generic_write_sync() to issue a
* REQ_FLUSH post write. This is slightly tricky because a single request here
* can be mapped into multiple disjoint IOs and only a subset of the IOs issued
* may be pure data writes. In that case, we still need to do a full data sync
* completion.
*
* When page faults are disabled and @dio_flags includes IOMAP_DIO_PARTIAL,
* __iomap_dio_rw can return a partial result if it encounters a non-resident
* page in @iter after preparing a transfer. In that case, the non-resident
* pages can be faulted in and the request resumed with @done_before set to the
* number of bytes previously transferred. The request will then complete with
* the correct total number of bytes transferred; this is essential for
* completing partial requests asynchronously.
*
* Returns -ENOTBLK In case of a page invalidation invalidation failure for
* writes. The callers needs to fall back to buffered I/O in this case.
*/
struct iomap_dio *
__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
unsigned int dio_flags, void *private, size_t done_before)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct iomap_iter iomi = {
.inode = inode,
.pos = iocb->ki_pos,
.len = iov_iter_count(iter),
.flags = IOMAP_DIRECT,
.private = private,
};
bool wait_for_completion =
is_sync_kiocb(iocb) || (dio_flags & IOMAP_DIO_FORCE_WAIT);
struct blk_plug plug;
struct iomap_dio *dio;
loff_t ret = 0;
trace_iomap_dio_rw_begin(iocb, iter, dio_flags, done_before);
if (!iomi.len)
return NULL;
dio = kmalloc(sizeof(*dio), GFP_KERNEL);
if (!dio)
return ERR_PTR(-ENOMEM);
dio->iocb = iocb;
atomic_set(&dio->ref, 1);
dio->size = 0;
dio->i_size = i_size_read(inode);
dio->dops = dops;
dio->error = 0;
dio->flags = 0;
dio->done_before = done_before;
dio->submit.iter = iter;
dio->submit.waiter = current;
if (iocb->ki_flags & IOCB_NOWAIT)
iomi.flags |= IOMAP_NOWAIT;
if (iov_iter_rw(iter) == READ) {
/* reads can always complete inline */
dio->flags |= IOMAP_DIO_INLINE_COMP;
if (iomi.pos >= dio->i_size)
goto out_free_dio;
if (user_backed_iter(iter))
dio->flags |= IOMAP_DIO_DIRTY;
ret = kiocb_write_and_wait(iocb, iomi.len);
if (ret)
goto out_free_dio;
} else {
iomi.flags |= IOMAP_WRITE;
dio->flags |= IOMAP_DIO_WRITE;
/*
* Flag as supporting deferred completions, if the issuer
* groks it. This can avoid a workqueue punt for writes.
* We may later clear this flag if we need to do other IO
* as part of this IO completion.
*/
if (iocb->ki_flags & IOCB_DIO_CALLER_COMP)
dio->flags |= IOMAP_DIO_CALLER_COMP;
if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) {
ret = -EAGAIN;
if (iomi.pos >= dio->i_size ||
iomi.pos + iomi.len > dio->i_size)
goto out_free_dio;
iomi.flags |= IOMAP_OVERWRITE_ONLY;
}
/* for data sync or sync, we need sync completion processing */
if (iocb_is_dsync(iocb)) {
dio->flags |= IOMAP_DIO_NEED_SYNC;
/*
* For datasync only writes, we optimistically try using
* WRITE_THROUGH for this IO. This flag requires either
* FUA writes through the device's write cache, or a
* normal write to a device without a volatile write
* cache. For the former, Any non-FUA write that occurs
* will clear this flag, hence we know before completion
* whether a cache flush is necessary.
*/
if (!(iocb->ki_flags & IOCB_SYNC))
dio->flags |= IOMAP_DIO_WRITE_THROUGH;
}
/*
* Try to invalidate cache pages for the range we are writing.
* If this invalidation fails, let the caller fall back to
* buffered I/O.
*/
ret = kiocb_invalidate_pages(iocb, iomi.len);
if (ret) {
if (ret != -EAGAIN) {
trace_iomap_dio_invalidate_fail(inode, iomi.pos,
iomi.len);
ret = -ENOTBLK;
}
goto out_free_dio;
}
if (!wait_for_completion && !inode->i_sb->s_dio_done_wq) {
ret = sb_init_dio_done_wq(inode->i_sb);
if (ret < 0)
goto out_free_dio;
}
}
inode_dio_begin(inode);
blk_start_plug(&plug);
while ((ret = iomap_iter(&iomi, ops)) > 0) {
iomi.processed = iomap_dio_iter(&iomi, dio);
/*
* We can only poll for single bio I/Os.
*/
iocb->ki_flags &= ~IOCB_HIPRI;
}
blk_finish_plug(&plug);
/*
* We only report that we've read data up to i_size.
* Revert iter to a state corresponding to that as some callers (such
* as the splice code) rely on it.
*/
if (iov_iter_rw(iter) == READ && iomi.pos >= dio->i_size)
iov_iter_revert(iter, iomi.pos - dio->i_size);
if (ret == -EFAULT && dio->size && (dio_flags & IOMAP_DIO_PARTIAL)) {
if (!(iocb->ki_flags & IOCB_NOWAIT))
wait_for_completion = true;
ret = 0;
}
/* magic error code to fall back to buffered I/O */
if (ret == -ENOTBLK) {
wait_for_completion = true;
ret = 0;
}
if (ret < 0)
iomap_dio_set_error(dio, ret);
/*
* If all the writes we issued were already written through to the
* media, we don't need to flush the cache on IO completion. Clear the
* sync flag for this case.
*/
if (dio->flags & IOMAP_DIO_WRITE_THROUGH)
dio->flags &= ~IOMAP_DIO_NEED_SYNC;
/*
* We are about to drop our additional submission reference, which
* might be the last reference to the dio. There are three different
* ways we can progress here:
*
* (a) If this is the last reference we will always complete and free
* the dio ourselves.
* (b) If this is not the last reference, and we serve an asynchronous
* iocb, we must never touch the dio after the decrement, the
* I/O completion handler will complete and free it.
* (c) If this is not the last reference, but we serve a synchronous
* iocb, the I/O completion handler will wake us up on the drop
* of the final reference, and we will complete and free it here
* after we got woken by the I/O completion handler.
*/
dio->wait_for_completion = wait_for_completion;
if (!atomic_dec_and_test(&dio->ref)) {
if (!wait_for_completion) {
trace_iomap_dio_rw_queued(inode, iomi.pos, iomi.len);
return ERR_PTR(-EIOCBQUEUED);
}
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (!READ_ONCE(dio->submit.waiter))
break;
blk_io_schedule();
}
__set_current_state(TASK_RUNNING);
}
return dio;
out_free_dio:
kfree(dio);
if (ret)
return ERR_PTR(ret);
return NULL;
}
EXPORT_SYMBOL_GPL(__iomap_dio_rw);
ssize_t
iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
unsigned int dio_flags, void *private, size_t done_before)
{
struct iomap_dio *dio;
dio = __iomap_dio_rw(iocb, iter, ops, dops, dio_flags, private,
done_before);
if (IS_ERR_OR_NULL(dio))
return PTR_ERR_OR_ZERO(dio);
return iomap_dio_complete(dio);
}
EXPORT_SYMBOL_GPL(iomap_dio_rw);
static int __init iomap_dio_init(void)
{
zero_page = alloc_pages(GFP_KERNEL | __GFP_ZERO,
IOMAP_ZERO_PAGE_ORDER);
if (!zero_page)
return -ENOMEM;
return 0;
}
fs_initcall(iomap_dio_init);
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