lkml.org 
[lkml]   [2023]   [Oct]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/2] pipe: remove pipe_full check with wrong head in pipe_write
Date
In pipe_write we have:
head = pipe->head;
if (!pipe_full(head, pipe->tail, pipe->max_usage))
pipe->head = head + 1;
/* write data to buffer at head */

/* supposed to check if pipe is full after write */
if (!pipe_full(head, pipe->tail, pipe->max_usage))
continue

The second pipe_full expects head after write but head before write is
used. Luckily, we will call pipe_full with correct reloaded pipe->head
in new loop cycle and stop writing correctly. Remove wrong pipe_full
check and simply continue to first pipe_full check after write done to
avoid unnecessary check.

Fixes: a194dfe6e6f6 ("pipe: Rearrange sequence in pipe_write() to preallocate slot")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
fs/pipe.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/pipe.c b/fs/pipe.c
index 2d88f73f585a..b19875720ff1 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -542,10 +542,9 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)

if (!iov_iter_count(from))
break;
- }

- if (!pipe_full(head, pipe->tail, pipe->max_usage))
continue;
+ }

/* Wait for buffer space to become available. */
if ((filp->f_flags & O_NONBLOCK) ||
--
2.30.0
\
 
 \ /
  Last update: 2023-10-08 03:48    [W:0.061 / U:0.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site