public inbox for [email protected]
 help / color / mirror / Atom feed
From: Dylan Yudaken <[email protected]>
To: Jens Axboe <[email protected]>,
	Pavel Begunkov <[email protected]>,
	<[email protected]>
Cc: <[email protected]>, Dylan Yudaken <[email protected]>
Subject: [PATCH v3 2/4] io_uring: update kiocb->ki_pos at execution time
Date: Tue, 22 Feb 2022 02:55:02 -0800	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

Update kiocb->ki_pos at execution time rather than in io_prep_rw().
io_prep_rw() happens before the job is enqueued to a worker and so the
offset might be read multiple times before being executed once.

Ensures that the file position in a set of _linked_ SQEs will be only
obtained after earlier SQEs have completed, and so will include their
incremented file position.

Signed-off-by: Dylan Yudaken <[email protected]>
---
 fs/io_uring.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1f9b4466c269..aba2a426a2d1 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3000,14 +3000,6 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT;
 
 	kiocb->ki_pos = READ_ONCE(sqe->off);
-	if (kiocb->ki_pos == -1) {
-		if (!(file->f_mode & FMODE_STREAM)) {
-			req->flags |= REQ_F_CUR_POS;
-			kiocb->ki_pos = file->f_pos;
-		} else {
-			kiocb->ki_pos = 0;
-		}
-	}
 	kiocb->ki_flags = iocb_flags(file);
 	ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags));
 	if (unlikely(ret))
@@ -3074,6 +3066,20 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
 	}
 }
 
+static inline void io_kiocb_update_pos(struct io_kiocb *req)
+{
+	struct kiocb *kiocb = &req->rw.kiocb;
+
+	if (kiocb->ki_pos == -1) {
+		if (!(req->file->f_mode & FMODE_STREAM)) {
+			req->flags |= REQ_F_CUR_POS;
+			kiocb->ki_pos = req->file->f_pos;
+		} else {
+			kiocb->ki_pos = 0;
+		}
+	}
+}
+
 static void kiocb_done(struct io_kiocb *req, ssize_t ret,
 		       unsigned int issue_flags)
 {
@@ -3662,6 +3668,8 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
 		kiocb->ki_flags &= ~IOCB_NOWAIT;
 	}
 
+	io_kiocb_update_pos(req);
+
 	ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), req->result);
 	if (unlikely(ret)) {
 		kfree(iovec);
@@ -3791,6 +3799,8 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
 		kiocb->ki_flags &= ~IOCB_NOWAIT;
 	}
 
+	io_kiocb_update_pos(req);
+
 	ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), req->result);
 	if (unlikely(ret))
 		goto out_free;
-- 
2.30.2


  parent reply	other threads:[~2022-02-22 10:55 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-22 10:55 [PATCH v3 0/4] io_uring: consistent behaviour with linked read/write Dylan Yudaken
2022-02-22 10:55 ` [PATCH v3 1/4] io_uring: remove duplicated calls to io_kiocb_ppos Dylan Yudaken
2022-02-23 23:06   ` Pavel Begunkov
2022-02-22 10:55 ` Dylan Yudaken [this message]
2022-02-23 23:06   ` [PATCH v3 2/4] io_uring: update kiocb->ki_pos at execution time Pavel Begunkov
2022-02-22 10:55 ` [PATCH v3 3/4] io_uring: do not recalculate ppos unnecessarily Dylan Yudaken
2022-02-23 23:07   ` Pavel Begunkov
2022-02-22 10:55 ` [PATCH v3 4/4] io_uring: pre-increment f_pos on rw Dylan Yudaken
2022-02-23 23:51 ` [PATCH v3 0/4] io_uring: consistent behaviour with linked read/write Jens Axboe
2022-02-24 10:45   ` Dylan Yudaken

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox