From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 3 Aug 2022 20:50:22 +0000 (-0700)
Subject: Merge tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel... 
X-Git-Tag: microblaze-v6.1~154
X-Git-Url: http://git.monstr.eu/?p=linux-2.6-microblaze.git;a=commitdiff_plain;h=5264406cdb66c7003eb3edf53c9773b1b20611b9

Merge tag 'pull-work.iov_iter-base' of git://git./linux/kernel/git/viro/vfs

Pull vfs iov_iter updates from Al Viro:
 "Part 1 - isolated cleanups and optimizations.

  One of the goals is to reduce the overhead of using ->read_iter() and
  ->write_iter() instead of ->read()/->write().

  new_sync_{read,write}() has a surprising amount of overhead, in
  particular inside iocb_flags(). That's the explanation for the
  beginning of the series is in this pile; it's not directly
  iov_iter-related, but it's a part of the same work..."

* tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  first_iovec_segment(): just return address
  iov_iter: massage calling conventions for first_{iovec,bvec}_segment()
  iov_iter: first_{iovec,bvec}_segment() - simplify a bit
  iov_iter: lift dealing with maxpages out of first_{iovec,bvec}_segment()
  iov_iter_get_pages{,_alloc}(): cap the maxsize with MAX_RW_COUNT
  iov_iter_bvec_advance(): don't bother with bvec_iter
  copy_page_{to,from}_iter(): switch iovec variants to generic
  keep iocb_flags() result cached in struct file
  iocb: delay evaluation of IS_SYNC(...) until we want to check IOCB_DSYNC
  struct file: use anonymous union member for rcuhead and llist
  btrfs: use IOMAP_DIO_NOSYNC
  teach iomap_dio_rw() to suppress dsync
  No need of likely/unlikely on calls of check_copy_size()
---

5264406cdb66c7003eb3edf53c9773b1b20611b9
diff --cc block/fops.c
index 92ee820e40fd,6e86931ab847..a564cd81340c
--- a/block/fops.c
+++ b/block/fops.c
@@@ -32,21 -32,14 +32,21 @@@ static int blkdev_get_block(struct inod
  	return 0;
  }
  
 -static unsigned int dio_bio_write_op(struct kiocb *iocb)
 +static blk_opf_t dio_bio_write_op(struct kiocb *iocb)
  {
 -	unsigned int op = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
 +	blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
  
  	/* avoid the need for a I/O completion work item */
- 	if (iocb->ki_flags & IOCB_DSYNC)
+ 	if (iocb_is_dsync(iocb))
 -		op |= REQ_FUA;
 -	return op;
 +		opf |= REQ_FUA;
 +	return opf;
 +}
 +
 +static bool blkdev_dio_unaligned(struct block_device *bdev, loff_t pos,
 +			      struct iov_iter *iter)
 +{
 +	return pos & (bdev_logical_block_size(bdev) - 1) ||
 +		!bdev_iter_is_aligned(bdev, iter);
  }
  
  #define DIO_INLINE_BIO_VECS 4
diff --cc include/linux/fs.h
index 76f09f3ee4a5,c82b9d442f56..cc64873d76c5
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@@ -2324,12 -2196,10 +2325,10 @@@ static inline bool sb_rdonly(const stru
  static inline bool HAS_UNMAPPED_ID(struct user_namespace *mnt_userns,
  				   struct inode *inode)
  {
 -	return !uid_valid(i_uid_into_mnt(mnt_userns, inode)) ||
 -	       !gid_valid(i_gid_into_mnt(mnt_userns, inode));
 +	return !vfsuid_valid(i_uid_into_vfsuid(mnt_userns, inode)) ||
 +	       !vfsgid_valid(i_gid_into_vfsgid(mnt_userns, inode));
  }
  
- static inline int iocb_flags(struct file *file);
- 
  static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
  {
  	*kiocb = (struct kiocb) {
diff --cc io_uring/rw.c
index 2b784795103c,000000000000..b20ba87e4926
mode 100644,000000..100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@@ -1,1049 -1,0 +1,1049 @@@
 +// SPDX-License-Identifier: GPL-2.0
 +#include <linux/kernel.h>
 +#include <linux/errno.h>
 +#include <linux/fs.h>
 +#include <linux/file.h>
 +#include <linux/blk-mq.h>
 +#include <linux/mm.h>
 +#include <linux/slab.h>
 +#include <linux/fsnotify.h>
 +#include <linux/poll.h>
 +#include <linux/nospec.h>
 +#include <linux/compat.h>
 +#include <linux/io_uring.h>
 +
 +#include <uapi/linux/io_uring.h>
 +
 +#include "io_uring.h"
 +#include "opdef.h"
 +#include "kbuf.h"
 +#include "rsrc.h"
 +#include "rw.h"
 +
 +struct io_rw {
 +	/* NOTE: kiocb has the file as the first member, so don't do it here */
 +	struct kiocb			kiocb;
 +	u64				addr;
 +	u32				len;
 +	rwf_t				flags;
 +};
 +
 +static inline bool io_file_supports_nowait(struct io_kiocb *req)
 +{
 +	return req->flags & REQ_F_SUPPORT_NOWAIT;
 +}
 +
 +int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 +{
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +	unsigned ioprio;
 +	int ret;
 +
 +	rw->kiocb.ki_pos = READ_ONCE(sqe->off);
 +	/* used for fixed read/write too - just read unconditionally */
 +	req->buf_index = READ_ONCE(sqe->buf_index);
 +
 +	if (req->opcode == IORING_OP_READ_FIXED ||
 +	    req->opcode == IORING_OP_WRITE_FIXED) {
 +		struct io_ring_ctx *ctx = req->ctx;
 +		u16 index;
 +
 +		if (unlikely(req->buf_index >= ctx->nr_user_bufs))
 +			return -EFAULT;
 +		index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
 +		req->imu = ctx->user_bufs[index];
 +		io_req_set_rsrc_node(req, ctx, 0);
 +	}
 +
 +	ioprio = READ_ONCE(sqe->ioprio);
 +	if (ioprio) {
 +		ret = ioprio_check_cap(ioprio);
 +		if (ret)
 +			return ret;
 +
 +		rw->kiocb.ki_ioprio = ioprio;
 +	} else {
 +		rw->kiocb.ki_ioprio = get_current_ioprio();
 +	}
 +
 +	rw->addr = READ_ONCE(sqe->addr);
 +	rw->len = READ_ONCE(sqe->len);
 +	rw->flags = READ_ONCE(sqe->rw_flags);
 +	return 0;
 +}
 +
 +void io_readv_writev_cleanup(struct io_kiocb *req)
 +{
 +	struct io_async_rw *io = req->async_data;
 +
 +	kfree(io->free_iovec);
 +}
 +
 +static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
 +{
 +	switch (ret) {
 +	case -EIOCBQUEUED:
 +		break;
 +	case -ERESTARTSYS:
 +	case -ERESTARTNOINTR:
 +	case -ERESTARTNOHAND:
 +	case -ERESTART_RESTARTBLOCK:
 +		/*
 +		 * We can't just restart the syscall, since previously
 +		 * submitted sqes may already be in progress. Just fail this
 +		 * IO with EINTR.
 +		 */
 +		ret = -EINTR;
 +		fallthrough;
 +	default:
 +		kiocb->ki_complete(kiocb, ret);
 +	}
 +}
 +
 +static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
 +{
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +
 +	if (rw->kiocb.ki_pos != -1)
 +		return &rw->kiocb.ki_pos;
 +
 +	if (!(req->file->f_mode & FMODE_STREAM)) {
 +		req->flags |= REQ_F_CUR_POS;
 +		rw->kiocb.ki_pos = req->file->f_pos;
 +		return &rw->kiocb.ki_pos;
 +	}
 +
 +	rw->kiocb.ki_pos = 0;
 +	return NULL;
 +}
 +
 +static void io_req_task_queue_reissue(struct io_kiocb *req)
 +{
 +	req->io_task_work.func = io_queue_iowq;
 +	io_req_task_work_add(req);
 +}
 +
 +#ifdef CONFIG_BLOCK
 +static bool io_resubmit_prep(struct io_kiocb *req)
 +{
 +	struct io_async_rw *io = req->async_data;
 +
 +	if (!req_has_async_data(req))
 +		return !io_req_prep_async(req);
 +	iov_iter_restore(&io->s.iter, &io->s.iter_state);
 +	return true;
 +}
 +
 +static bool io_rw_should_reissue(struct io_kiocb *req)
 +{
 +	umode_t mode = file_inode(req->file)->i_mode;
 +	struct io_ring_ctx *ctx = req->ctx;
 +
 +	if (!S_ISBLK(mode) && !S_ISREG(mode))
 +		return false;
 +	if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() &&
 +	    !(ctx->flags & IORING_SETUP_IOPOLL)))
 +		return false;
 +	/*
 +	 * If ref is dying, we might be running poll reap from the exit work.
 +	 * Don't attempt to reissue from that path, just let it fail with
 +	 * -EAGAIN.
 +	 */
 +	if (percpu_ref_is_dying(&ctx->refs))
 +		return false;
 +	/*
 +	 * Play it safe and assume not safe to re-import and reissue if we're
 +	 * not in the original thread group (or in task context).
 +	 */
 +	if (!same_thread_group(req->task, current) || !in_task())
 +		return false;
 +	return true;
 +}
 +#else
 +static bool io_resubmit_prep(struct io_kiocb *req)
 +{
 +	return false;
 +}
 +static bool io_rw_should_reissue(struct io_kiocb *req)
 +{
 +	return false;
 +}
 +#endif
 +
 +static void kiocb_end_write(struct io_kiocb *req)
 +{
 +	/*
 +	 * Tell lockdep we inherited freeze protection from submission
 +	 * thread.
 +	 */
 +	if (req->flags & REQ_F_ISREG) {
 +		struct super_block *sb = file_inode(req->file)->i_sb;
 +
 +		__sb_writers_acquired(sb, SB_FREEZE_WRITE);
 +		sb_end_write(sb);
 +	}
 +}
 +
 +static bool __io_complete_rw_common(struct io_kiocb *req, long res)
 +{
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +
 +	if (rw->kiocb.ki_flags & IOCB_WRITE) {
 +		kiocb_end_write(req);
 +		fsnotify_modify(req->file);
 +	} else {
 +		fsnotify_access(req->file);
 +	}
 +	if (unlikely(res != req->cqe.res)) {
 +		if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
 +		    io_rw_should_reissue(req)) {
 +			req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
 +			return true;
 +		}
 +		req_set_fail(req);
 +		req->cqe.res = res;
 +	}
 +	return false;
 +}
 +
 +static void io_complete_rw(struct kiocb *kiocb, long res)
 +{
 +	struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
 +	struct io_kiocb *req = cmd_to_io_kiocb(rw);
 +
 +	if (__io_complete_rw_common(req, res))
 +		return;
 +	io_req_set_res(req, res, 0);
 +	req->io_task_work.func = io_req_task_complete;
 +	io_req_task_work_add(req);
 +}
 +
 +static void io_complete_rw_iopoll(struct kiocb *kiocb, long res)
 +{
 +	struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
 +	struct io_kiocb *req = cmd_to_io_kiocb(rw);
 +
 +	if (kiocb->ki_flags & IOCB_WRITE)
 +		kiocb_end_write(req);
 +	if (unlikely(res != req->cqe.res)) {
 +		if (res == -EAGAIN && io_rw_should_reissue(req)) {
 +			req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
 +			return;
 +		}
 +		req->cqe.res = res;
 +	}
 +
 +	/* order with io_iopoll_complete() checking ->iopoll_completed */
 +	smp_store_release(&req->iopoll_completed, 1);
 +}
 +
 +static int kiocb_done(struct io_kiocb *req, ssize_t ret,
 +		       unsigned int issue_flags)
 +{
 +	struct io_async_rw *io = req->async_data;
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +
 +	/* add previously done IO, if any */
 +	if (req_has_async_data(req) && io->bytes_done > 0) {
 +		if (ret < 0)
 +			ret = io->bytes_done;
 +		else
 +			ret += io->bytes_done;
 +	}
 +
 +	if (req->flags & REQ_F_CUR_POS)
 +		req->file->f_pos = rw->kiocb.ki_pos;
 +	if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) {
 +		if (!__io_complete_rw_common(req, ret)) {
 +			io_req_set_res(req, req->cqe.res,
 +				       io_put_kbuf(req, issue_flags));
 +			return IOU_OK;
 +		}
 +	} else {
 +		io_rw_done(&rw->kiocb, ret);
 +	}
 +
 +	if (req->flags & REQ_F_REISSUE) {
 +		req->flags &= ~REQ_F_REISSUE;
 +		if (io_resubmit_prep(req))
 +			io_req_task_queue_reissue(req);
 +		else
 +			io_req_task_queue_fail(req, ret);
 +	}
 +	return IOU_ISSUE_SKIP_COMPLETE;
 +}
 +
 +#ifdef CONFIG_COMPAT
 +static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
 +				unsigned int issue_flags)
 +{
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +	struct compat_iovec __user *uiov;
 +	compat_ssize_t clen;
 +	void __user *buf;
 +	size_t len;
 +
 +	uiov = u64_to_user_ptr(rw->addr);
 +	if (!access_ok(uiov, sizeof(*uiov)))
 +		return -EFAULT;
 +	if (__get_user(clen, &uiov->iov_len))
 +		return -EFAULT;
 +	if (clen < 0)
 +		return -EINVAL;
 +
 +	len = clen;
 +	buf = io_buffer_select(req, &len, issue_flags);
 +	if (!buf)
 +		return -ENOBUFS;
 +	rw->addr = (unsigned long) buf;
 +	iov[0].iov_base = buf;
 +	rw->len = iov[0].iov_len = (compat_size_t) len;
 +	return 0;
 +}
 +#endif
 +
 +static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
 +				      unsigned int issue_flags)
 +{
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +	struct iovec __user *uiov = u64_to_user_ptr(rw->addr);
 +	void __user *buf;
 +	ssize_t len;
 +
 +	if (copy_from_user(iov, uiov, sizeof(*uiov)))
 +		return -EFAULT;
 +
 +	len = iov[0].iov_len;
 +	if (len < 0)
 +		return -EINVAL;
 +	buf = io_buffer_select(req, &len, issue_flags);
 +	if (!buf)
 +		return -ENOBUFS;
 +	rw->addr = (unsigned long) buf;
 +	iov[0].iov_base = buf;
 +	rw->len = iov[0].iov_len = len;
 +	return 0;
 +}
 +
 +static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
 +				    unsigned int issue_flags)
 +{
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +
 +	if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) {
 +		iov[0].iov_base = u64_to_user_ptr(rw->addr);
 +		iov[0].iov_len = rw->len;
 +		return 0;
 +	}
 +	if (rw->len != 1)
 +		return -EINVAL;
 +
 +#ifdef CONFIG_COMPAT
 +	if (req->ctx->compat)
 +		return io_compat_import(req, iov, issue_flags);
 +#endif
 +
 +	return __io_iov_buffer_select(req, iov, issue_flags);
 +}
 +
 +static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req,
 +				       struct io_rw_state *s,
 +				       unsigned int issue_flags)
 +{
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +	struct iov_iter *iter = &s->iter;
 +	u8 opcode = req->opcode;
 +	struct iovec *iovec;
 +	void __user *buf;
 +	size_t sqe_len;
 +	ssize_t ret;
 +
 +	if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
 +		ret = io_import_fixed(ddir, iter, req->imu, rw->addr, rw->len);
 +		if (ret)
 +			return ERR_PTR(ret);
 +		return NULL;
 +	}
 +
 +	buf = u64_to_user_ptr(rw->addr);
 +	sqe_len = rw->len;
 +
 +	if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
 +		if (io_do_buffer_select(req)) {
 +			buf = io_buffer_select(req, &sqe_len, issue_flags);
 +			if (!buf)
 +				return ERR_PTR(-ENOBUFS);
 +			rw->addr = (unsigned long) buf;
 +			rw->len = sqe_len;
 +		}
 +
 +		ret = import_single_range(ddir, buf, sqe_len, s->fast_iov, iter);
 +		if (ret)
 +			return ERR_PTR(ret);
 +		return NULL;
 +	}
 +
 +	iovec = s->fast_iov;
 +	if (req->flags & REQ_F_BUFFER_SELECT) {
 +		ret = io_iov_buffer_select(req, iovec, issue_flags);
 +		if (ret)
 +			return ERR_PTR(ret);
 +		iov_iter_init(iter, ddir, iovec, 1, iovec->iov_len);
 +		return NULL;
 +	}
 +
 +	ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter,
 +			      req->ctx->compat);
 +	if (unlikely(ret < 0))
 +		return ERR_PTR(ret);
 +	return iovec;
 +}
 +
 +static inline int io_import_iovec(int rw, struct io_kiocb *req,
 +				  struct iovec **iovec, struct io_rw_state *s,
 +				  unsigned int issue_flags)
 +{
 +	*iovec = __io_import_iovec(rw, req, s, issue_flags);
 +	if (unlikely(IS_ERR(*iovec)))
 +		return PTR_ERR(*iovec);
 +
 +	iov_iter_save_state(&s->iter, &s->iter_state);
 +	return 0;
 +}
 +
 +static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
 +{
 +	return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
 +}
 +
 +/*
 + * For files that don't have ->read_iter() and ->write_iter(), handle them
 + * by looping over ->read() or ->write() manually.
 + */
 +static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
 +{
 +	struct kiocb *kiocb = &rw->kiocb;
 +	struct file *file = kiocb->ki_filp;
 +	ssize_t ret = 0;
 +	loff_t *ppos;
 +
 +	/*
 +	 * Don't support polled IO through this interface, and we can't
 +	 * support non-blocking either. For the latter, this just causes
 +	 * the kiocb to be handled from an async context.
 +	 */
 +	if (kiocb->ki_flags & IOCB_HIPRI)
 +		return -EOPNOTSUPP;
 +	if ((kiocb->ki_flags & IOCB_NOWAIT) &&
 +	    !(kiocb->ki_filp->f_flags & O_NONBLOCK))
 +		return -EAGAIN;
 +
 +	ppos = io_kiocb_ppos(kiocb);
 +
 +	while (iov_iter_count(iter)) {
 +		struct iovec iovec;
 +		ssize_t nr;
 +
 +		if (!iov_iter_is_bvec(iter)) {
 +			iovec = iov_iter_iovec(iter);
 +		} else {
 +			iovec.iov_base = u64_to_user_ptr(rw->addr);
 +			iovec.iov_len = rw->len;
 +		}
 +
 +		if (ddir == READ) {
 +			nr = file->f_op->read(file, iovec.iov_base,
 +					      iovec.iov_len, ppos);
 +		} else {
 +			nr = file->f_op->write(file, iovec.iov_base,
 +					       iovec.iov_len, ppos);
 +		}
 +
 +		if (nr < 0) {
 +			if (!ret)
 +				ret = nr;
 +			break;
 +		}
 +		ret += nr;
 +		if (!iov_iter_is_bvec(iter)) {
 +			iov_iter_advance(iter, nr);
 +		} else {
 +			rw->addr += nr;
 +			rw->len -= nr;
 +			if (!rw->len)
 +				break;
 +		}
 +		if (nr != iovec.iov_len)
 +			break;
 +	}
 +
 +	return ret;
 +}
 +
 +static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
 +			  const struct iovec *fast_iov, struct iov_iter *iter)
 +{
 +	struct io_async_rw *io = req->async_data;
 +
 +	memcpy(&io->s.iter, iter, sizeof(*iter));
 +	io->free_iovec = iovec;
 +	io->bytes_done = 0;
 +	/* can only be fixed buffers, no need to do anything */
 +	if (iov_iter_is_bvec(iter))
 +		return;
 +	if (!iovec) {
 +		unsigned iov_off = 0;
 +
 +		io->s.iter.iov = io->s.fast_iov;
 +		if (iter->iov != fast_iov) {
 +			iov_off = iter->iov - fast_iov;
 +			io->s.iter.iov += iov_off;
 +		}
 +		if (io->s.fast_iov != fast_iov)
 +			memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off,
 +			       sizeof(struct iovec) * iter->nr_segs);
 +	} else {
 +		req->flags |= REQ_F_NEED_CLEANUP;
 +	}
 +}
 +
 +static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
 +			     struct io_rw_state *s, bool force)
 +{
 +	if (!force && !io_op_defs[req->opcode].prep_async)
 +		return 0;
 +	if (!req_has_async_data(req)) {
 +		struct io_async_rw *iorw;
 +
 +		if (io_alloc_async_data(req)) {
 +			kfree(iovec);
 +			return -ENOMEM;
 +		}
 +
 +		io_req_map_rw(req, iovec, s->fast_iov, &s->iter);
 +		iorw = req->async_data;
 +		/* we've copied and mapped the iter, ensure state is saved */
 +		iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state);
 +	}
 +	return 0;
 +}
 +
 +static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
 +{
 +	struct io_async_rw *iorw = req->async_data;
 +	struct iovec *iov;
 +	int ret;
 +
 +	/* submission path, ->uring_lock should already be taken */
 +	ret = io_import_iovec(rw, req, &iov, &iorw->s, 0);
 +	if (unlikely(ret < 0))
 +		return ret;
 +
 +	iorw->bytes_done = 0;
 +	iorw->free_iovec = iov;
 +	if (iov)
 +		req->flags |= REQ_F_NEED_CLEANUP;
 +	return 0;
 +}
 +
 +int io_readv_prep_async(struct io_kiocb *req)
 +{
 +	return io_rw_prep_async(req, READ);
 +}
 +
 +int io_writev_prep_async(struct io_kiocb *req)
 +{
 +	return io_rw_prep_async(req, WRITE);
 +}
 +
 +/*
 + * This is our waitqueue callback handler, registered through __folio_lock_async()
 + * when we initially tried to do the IO with the iocb armed our waitqueue.
 + * This gets called when the page is unlocked, and we generally expect that to
 + * happen when the page IO is completed and the page is now uptodate. This will
 + * queue a task_work based retry of the operation, attempting to copy the data
 + * again. If the latter fails because the page was NOT uptodate, then we will
 + * do a thread based blocking retry of the operation. That's the unexpected
 + * slow path.
 + */
 +static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
 +			     int sync, void *arg)
 +{
 +	struct wait_page_queue *wpq;
 +	struct io_kiocb *req = wait->private;
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +	struct wait_page_key *key = arg;
 +
 +	wpq = container_of(wait, struct wait_page_queue, wait);
 +
 +	if (!wake_page_match(wpq, key))
 +		return 0;
 +
 +	rw->kiocb.ki_flags &= ~IOCB_WAITQ;
 +	list_del_init(&wait->entry);
 +	io_req_task_queue(req);
 +	return 1;
 +}
 +
 +/*
 + * This controls whether a given IO request should be armed for async page
 + * based retry. If we return false here, the request is handed to the async
 + * worker threads for retry. If we're doing buffered reads on a regular file,
 + * we prepare a private wait_page_queue entry and retry the operation. This
 + * will either succeed because the page is now uptodate and unlocked, or it
 + * will register a callback when the page is unlocked at IO completion. Through
 + * that callback, io_uring uses task_work to setup a retry of the operation.
 + * That retry will attempt the buffered read again. The retry will generally
 + * succeed, or in rare cases where it fails, we then fall back to using the
 + * async worker threads for a blocking retry.
 + */
 +static bool io_rw_should_retry(struct io_kiocb *req)
 +{
 +	struct io_async_rw *io = req->async_data;
 +	struct wait_page_queue *wait = &io->wpq;
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +	struct kiocb *kiocb = &rw->kiocb;
 +
 +	/* never retry for NOWAIT, we just complete with -EAGAIN */
 +	if (req->flags & REQ_F_NOWAIT)
 +		return false;
 +
 +	/* Only for buffered IO */
 +	if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
 +		return false;
 +
 +	/*
 +	 * just use poll if we can, and don't attempt if the fs doesn't
 +	 * support callback based unlocks
 +	 */
 +	if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
 +		return false;
 +
 +	wait->wait.func = io_async_buf_func;
 +	wait->wait.private = req;
 +	wait->wait.flags = 0;
 +	INIT_LIST_HEAD(&wait->wait.entry);
 +	kiocb->ki_flags |= IOCB_WAITQ;
 +	kiocb->ki_flags &= ~IOCB_NOWAIT;
 +	kiocb->ki_waitq = wait;
 +	return true;
 +}
 +
 +static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter)
 +{
 +	struct file *file = rw->kiocb.ki_filp;
 +
 +	if (likely(file->f_op->read_iter))
 +		return call_read_iter(file, &rw->kiocb, iter);
 +	else if (file->f_op->read)
 +		return loop_rw_iter(READ, rw, iter);
 +	else
 +		return -EINVAL;
 +}
 +
 +static bool need_complete_io(struct io_kiocb *req)
 +{
 +	return req->flags & REQ_F_ISREG ||
 +		S_ISBLK(file_inode(req->file)->i_mode);
 +}
 +
 +static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
 +{
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +	struct kiocb *kiocb = &rw->kiocb;
 +	struct io_ring_ctx *ctx = req->ctx;
 +	struct file *file = req->file;
 +	int ret;
 +
 +	if (unlikely(!file || !(file->f_mode & mode)))
 +		return -EBADF;
 +
 +	if (!io_req_ffs_set(req))
 +		req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT;
 +
- 	kiocb->ki_flags = iocb_flags(file);
++	kiocb->ki_flags = file->f_iocb_flags;
 +	ret = kiocb_set_rw_flags(kiocb, rw->flags);
 +	if (unlikely(ret))
 +		return ret;
 +
 +	/*
 +	 * If the file is marked O_NONBLOCK, still allow retry for it if it
 +	 * supports async. Otherwise it's impossible to use O_NONBLOCK files
 +	 * reliably. If not, or it IOCB_NOWAIT is set, don't retry.
 +	 */
 +	if ((kiocb->ki_flags & IOCB_NOWAIT) ||
 +	    ((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req)))
 +		req->flags |= REQ_F_NOWAIT;
 +
 +	if (ctx->flags & IORING_SETUP_IOPOLL) {
 +		if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll)
 +			return -EOPNOTSUPP;
 +
 +		kiocb->private = NULL;
 +		kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE;
 +		kiocb->ki_complete = io_complete_rw_iopoll;
 +		req->iopoll_completed = 0;
 +	} else {
 +		if (kiocb->ki_flags & IOCB_HIPRI)
 +			return -EINVAL;
 +		kiocb->ki_complete = io_complete_rw;
 +	}
 +
 +	return 0;
 +}
 +
 +int io_read(struct io_kiocb *req, unsigned int issue_flags)
 +{
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +	struct io_rw_state __s, *s = &__s;
 +	struct iovec *iovec;
 +	struct kiocb *kiocb = &rw->kiocb;
 +	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
 +	struct io_async_rw *io;
 +	ssize_t ret, ret2;
 +	loff_t *ppos;
 +
 +	if (!req_has_async_data(req)) {
 +		ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
 +		if (unlikely(ret < 0))
 +			return ret;
 +	} else {
 +		io = req->async_data;
 +		s = &io->s;
 +
 +		/*
 +		 * Safe and required to re-import if we're using provided
 +		 * buffers, as we dropped the selected one before retry.
 +		 */
 +		if (io_do_buffer_select(req)) {
 +			ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
 +			if (unlikely(ret < 0))
 +				return ret;
 +		}
 +
 +		/*
 +		 * We come here from an earlier attempt, restore our state to
 +		 * match in case it doesn't. It's cheap enough that we don't
 +		 * need to make this conditional.
 +		 */
 +		iov_iter_restore(&s->iter, &s->iter_state);
 +		iovec = NULL;
 +	}
 +	ret = io_rw_init_file(req, FMODE_READ);
 +	if (unlikely(ret)) {
 +		kfree(iovec);
 +		return ret;
 +	}
 +	req->cqe.res = iov_iter_count(&s->iter);
 +
 +	if (force_nonblock) {
 +		/* If the file doesn't support async, just async punt */
 +		if (unlikely(!io_file_supports_nowait(req))) {
 +			ret = io_setup_async_rw(req, iovec, s, true);
 +			return ret ?: -EAGAIN;
 +		}
 +		kiocb->ki_flags |= IOCB_NOWAIT;
 +	} else {
 +		/* Ensure we clear previously set non-block flag */
 +		kiocb->ki_flags &= ~IOCB_NOWAIT;
 +	}
 +
 +	ppos = io_kiocb_update_pos(req);
 +
 +	ret = rw_verify_area(READ, req->file, ppos, req->cqe.res);
 +	if (unlikely(ret)) {
 +		kfree(iovec);
 +		return ret;
 +	}
 +
 +	ret = io_iter_do_read(rw, &s->iter);
 +
 +	if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
 +		req->flags &= ~REQ_F_REISSUE;
 +		/* if we can poll, just do that */
 +		if (req->opcode == IORING_OP_READ && file_can_poll(req->file))
 +			return -EAGAIN;
 +		/* IOPOLL retry should happen for io-wq threads */
 +		if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
 +			goto done;
 +		/* no retry on NONBLOCK nor RWF_NOWAIT */
 +		if (req->flags & REQ_F_NOWAIT)
 +			goto done;
 +		ret = 0;
 +	} else if (ret == -EIOCBQUEUED) {
 +		if (iovec)
 +			kfree(iovec);
 +		return IOU_ISSUE_SKIP_COMPLETE;
 +	} else if (ret == req->cqe.res || ret <= 0 || !force_nonblock ||
 +		   (req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) {
 +		/* read all, failed, already did sync or don't want to retry */
 +		goto done;
 +	}
 +
 +	/*
 +	 * Don't depend on the iter state matching what was consumed, or being
 +	 * untouched in case of error. Restore it and we'll advance it
 +	 * manually if we need to.
 +	 */
 +	iov_iter_restore(&s->iter, &s->iter_state);
 +
 +	ret2 = io_setup_async_rw(req, iovec, s, true);
 +	if (ret2)
 +		return ret2;
 +
 +	iovec = NULL;
 +	io = req->async_data;
 +	s = &io->s;
 +	/*
 +	 * Now use our persistent iterator and state, if we aren't already.
 +	 * We've restored and mapped the iter to match.
 +	 */
 +
 +	do {
 +		/*
 +		 * We end up here because of a partial read, either from
 +		 * above or inside this loop. Advance the iter by the bytes
 +		 * that were consumed.
 +		 */
 +		iov_iter_advance(&s->iter, ret);
 +		if (!iov_iter_count(&s->iter))
 +			break;
 +		io->bytes_done += ret;
 +		iov_iter_save_state(&s->iter, &s->iter_state);
 +
 +		/* if we can retry, do so with the callbacks armed */
 +		if (!io_rw_should_retry(req)) {
 +			kiocb->ki_flags &= ~IOCB_WAITQ;
 +			return -EAGAIN;
 +		}
 +
 +		/*
 +		 * Now retry read with the IOCB_WAITQ parts set in the iocb. If
 +		 * we get -EIOCBQUEUED, then we'll get a notification when the
 +		 * desired page gets unlocked. We can also get a partial read
 +		 * here, and if we do, then just retry at the new offset.
 +		 */
 +		ret = io_iter_do_read(rw, &s->iter);
 +		if (ret == -EIOCBQUEUED)
 +			return IOU_ISSUE_SKIP_COMPLETE;
 +		/* we got some bytes, but not all. retry. */
 +		kiocb->ki_flags &= ~IOCB_WAITQ;
 +		iov_iter_restore(&s->iter, &s->iter_state);
 +	} while (ret > 0);
 +done:
 +	/* it's faster to check here then delegate to kfree */
 +	if (iovec)
 +		kfree(iovec);
 +	return kiocb_done(req, ret, issue_flags);
 +}
 +
 +int io_write(struct io_kiocb *req, unsigned int issue_flags)
 +{
 +	struct io_rw *rw = io_kiocb_to_cmd(req);
 +	struct io_rw_state __s, *s = &__s;
 +	struct iovec *iovec;
 +	struct kiocb *kiocb = &rw->kiocb;
 +	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
 +	ssize_t ret, ret2;
 +	loff_t *ppos;
 +
 +	if (!req_has_async_data(req)) {
 +		ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags);
 +		if (unlikely(ret < 0))
 +			return ret;
 +	} else {
 +		struct io_async_rw *io = req->async_data;
 +
 +		s = &io->s;
 +		iov_iter_restore(&s->iter, &s->iter_state);
 +		iovec = NULL;
 +	}
 +	ret = io_rw_init_file(req, FMODE_WRITE);
 +	if (unlikely(ret)) {
 +		kfree(iovec);
 +		return ret;
 +	}
 +	req->cqe.res = iov_iter_count(&s->iter);
 +
 +	if (force_nonblock) {
 +		/* If the file doesn't support async, just async punt */
 +		if (unlikely(!io_file_supports_nowait(req)))
 +			goto copy_iov;
 +
 +		/* File path supports NOWAIT for non-direct_IO only for block devices. */
 +		if (!(kiocb->ki_flags & IOCB_DIRECT) &&
 +			!(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) &&
 +			(req->flags & REQ_F_ISREG))
 +			goto copy_iov;
 +
 +		kiocb->ki_flags |= IOCB_NOWAIT;
 +	} else {
 +		/* Ensure we clear previously set non-block flag */
 +		kiocb->ki_flags &= ~IOCB_NOWAIT;
 +	}
 +
 +	ppos = io_kiocb_update_pos(req);
 +
 +	ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res);
 +	if (unlikely(ret)) {
 +		kfree(iovec);
 +		return ret;
 +	}
 +
 +	/*
 +	 * Open-code file_start_write here to grab freeze protection,
 +	 * which will be released by another thread in
 +	 * io_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 (req->flags & REQ_F_ISREG) {
 +		sb_start_write(file_inode(req->file)->i_sb);
 +		__sb_writers_release(file_inode(req->file)->i_sb,
 +					SB_FREEZE_WRITE);
 +	}
 +	kiocb->ki_flags |= IOCB_WRITE;
 +
 +	if (likely(req->file->f_op->write_iter))
 +		ret2 = call_write_iter(req->file, kiocb, &s->iter);
 +	else if (req->file->f_op->write)
 +		ret2 = loop_rw_iter(WRITE, rw, &s->iter);
 +	else
 +		ret2 = -EINVAL;
 +
 +	if (req->flags & REQ_F_REISSUE) {
 +		req->flags &= ~REQ_F_REISSUE;
 +		ret2 = -EAGAIN;
 +	}
 +
 +	/*
 +	 * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
 +	 * retry them without IOCB_NOWAIT.
 +	 */
 +	if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
 +		ret2 = -EAGAIN;
 +	/* no retry on NONBLOCK nor RWF_NOWAIT */
 +	if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
 +		goto done;
 +	if (!force_nonblock || ret2 != -EAGAIN) {
 +		/* IOPOLL retry should happen for io-wq threads */
 +		if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))
 +			goto copy_iov;
 +
 +		if (ret2 != req->cqe.res && ret2 >= 0 && need_complete_io(req)) {
 +			struct io_async_rw *rw;
 +
 +			trace_io_uring_short_write(req->ctx, kiocb->ki_pos - ret2,
 +						req->cqe.res, ret2);
 +
 +			/* This is a partial write. The file pos has already been
 +			 * updated, setup the async struct to complete the request
 +			 * in the worker. Also update bytes_done to account for
 +			 * the bytes already written.
 +			 */
 +			iov_iter_save_state(&s->iter, &s->iter_state);
 +			ret = io_setup_async_rw(req, iovec, s, true);
 +
 +			rw = req->async_data;
 +			if (rw)
 +				rw->bytes_done += ret2;
 +
 +			if (kiocb->ki_flags & IOCB_WRITE)
 +				kiocb_end_write(req);
 +			return ret ? ret : -EAGAIN;
 +		}
 +done:
 +		ret = kiocb_done(req, ret2, issue_flags);
 +	} else {
 +copy_iov:
 +		iov_iter_restore(&s->iter, &s->iter_state);
 +		ret = io_setup_async_rw(req, iovec, s, false);
 +		if (!ret) {
 +			if (kiocb->ki_flags & IOCB_WRITE)
 +				kiocb_end_write(req);
 +			return -EAGAIN;
 +		}
 +		return ret;
 +	}
 +	/* it's reportedly faster than delegating the null check to kfree() */
 +	if (iovec)
 +		kfree(iovec);
 +	return ret;
 +}
 +
 +static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)
 +{
 +	io_commit_cqring_flush(ctx);
 +	if (ctx->flags & IORING_SETUP_SQPOLL)
 +		io_cqring_wake(ctx);
 +}
 +
 +int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
 +{
 +	struct io_wq_work_node *pos, *start, *prev;
 +	unsigned int poll_flags = BLK_POLL_NOSLEEP;
 +	DEFINE_IO_COMP_BATCH(iob);
 +	int nr_events = 0;
 +
 +	/*
 +	 * Only spin for completions if we don't have multiple devices hanging
 +	 * off our complete list.
 +	 */
 +	if (ctx->poll_multi_queue || force_nonspin)
 +		poll_flags |= BLK_POLL_ONESHOT;
 +
 +	wq_list_for_each(pos, start, &ctx->iopoll_list) {
 +		struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
 +		struct io_rw *rw = io_kiocb_to_cmd(req);
 +		int ret;
 +
 +		/*
 +		 * Move completed and retryable entries to our local lists.
 +		 * If we find a request that requires polling, break out
 +		 * and complete those lists first, if we have entries there.
 +		 */
 +		if (READ_ONCE(req->iopoll_completed))
 +			break;
 +
 +		ret = rw->kiocb.ki_filp->f_op->iopoll(&rw->kiocb, &iob, poll_flags);
 +		if (unlikely(ret < 0))
 +			return ret;
 +		else if (ret)
 +			poll_flags |= BLK_POLL_ONESHOT;
 +
 +		/* iopoll may have completed current req */
 +		if (!rq_list_empty(iob.req_list) ||
 +		    READ_ONCE(req->iopoll_completed))
 +			break;
 +	}
 +
 +	if (!rq_list_empty(iob.req_list))
 +		iob.complete(&iob);
 +	else if (!pos)
 +		return 0;
 +
 +	prev = start;
 +	wq_list_for_each_resume(pos, prev) {
 +		struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
 +
 +		/* order with io_complete_rw_iopoll(), e.g. ->result updates */
 +		if (!smp_load_acquire(&req->iopoll_completed))
 +			break;
 +		nr_events++;
 +		if (unlikely(req->flags & REQ_F_CQE_SKIP))
 +			continue;
 +
 +		req->cqe.flags = io_put_kbuf(req, 0);
 +		__io_fill_cqe_req(req->ctx, req);
 +	}
 +
 +	if (unlikely(!nr_events))
 +		return 0;
 +
 +	io_commit_cqring(ctx);
 +	io_cqring_ev_posted_iopoll(ctx);
 +	pos = start ? start->next : ctx->iopoll_list.first;
 +	wq_list_cut(&ctx->iopoll_list, prev, start);
 +	io_free_batch_list(ctx, pos);
 +	return nr_events;
 +}