On Tue, Feb 18, 2020 at 10:28:23AM -0800, Linus Torvalds wrote:
On Tue, Feb 18, 2020 at 10:20 AM Matthew Wilcox willy@infradead.org wrote:
You don't want to move wake_up_partner() up and call it from pipe_release()?
I was actually thinking of going the other way - two of three users of wake_up_partner() are redundantly waking up the wrong side, and the third user is pointlessly written too.
So I was _thinking_ of a patch like the appended (which is on top of the previous patch), but ended up not doing it. Until you brought it up.
But I won't bother committing this, since it shouldn't really matter.
I run CRIU tests on the kernel with both these patches. Everything work as expected. Thank you for the fix.
Linus
fs/pipe.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/fs/pipe.c b/fs/pipe.c index 2144507447c5..79ba61430f9c 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -1025,12 +1025,6 @@ static int wait_for_partner(struct pipe_inode_info *pipe, unsigned int *cnt) return cur == *cnt ? -ERESTARTSYS : 0; } -static void wake_up_partner(struct pipe_inode_info *pipe) -{
- wake_up_interruptible_all(&pipe->rd_wait);
- wake_up_interruptible_all(&pipe->wr_wait);
-}
static int fifo_open(struct inode *inode, struct file *filp) { struct pipe_inode_info *pipe; @@ -1078,7 +1072,7 @@ static int fifo_open(struct inode *inode, struct file *filp) */ pipe->r_counter++; if (pipe->readers++ == 0)
wake_up_partner(pipe);
wake_up_interruptible_all(&pipe->wr_wait);if (!is_pipe && !pipe->writers) { if ((filp->f_flags & O_NONBLOCK)) { @@ -1104,7 +1098,7 @@ static int fifo_open(struct inode *inode, struct file *filp) pipe->w_counter++; if (!pipe->writers++)
wake_up_partner(pipe);
wake_up_interruptible_all(&pipe->rd_wait);if (!is_pipe && !pipe->readers) { if (wait_for_partner(pipe, &pipe->r_counter)) @@ -1120,12 +1114,12 @@ static int fifo_open(struct inode *inode, struct file *filp) * the process can at least talk to itself. */
pipe->readers++;pipe->writers++;
if (pipe->readers++ == 0)wake_up_interruptible_all(&pipe->wr_wait);if (pipe->writers++ == 0)wake_up_interruptible_all(&pipe->rd_wait);
if (pipe->readers == 1 || pipe->writers == 1)wake_up_partner(pipe);default: