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authorAl Viro <viro@zeniv.linux.org.uk>2013-03-21 02:21:19 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2013-04-09 14:12:59 -0400
commitba5bb147330a8737b6b5a812cc774c79c070704b (patch)
tree3043bd880634f47275a2083c53ed98ce2c1c70bc /include/linux/pipe_fs_i.h
parent18c03cfd403b88852f75f200206983ee6df28423 (diff)
pipe: take allocation and freeing of pipe_inode_info out of ->i_mutex
* new field - pipe->files; number of struct file over that pipe (all sharing the same inode, of course); protected by inode->i_lock. * pipe_release() decrements pipe->files, clears inode->i_pipe when if the counter has reached 0 (all under ->i_lock) and, in that case, frees pipe after having done pipe_unlock() * fifo_open() starts with grabbing ->i_lock, and either bumps pipe->files if ->i_pipe was non-NULL or allocates a new pipe (dropping and regaining ->i_lock) and rechecks ->i_pipe; if it's still NULL, inserts new pipe there, otherwise bumps ->i_pipe->files and frees the one we'd allocated. At that point we know that ->i_pipe is non-NULL and won't go away, so we can do pipe_lock() on it and proceed as we used to. If we end up failing, decrement pipe->files and if it reaches 0 clear ->i_pipe and free the sucker after pipe_unlock(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/pipe_fs_i.h')
-rw-r--r--include/linux/pipe_fs_i.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index ad1a427b5267..59778e1c9c08 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -34,6 +34,7 @@ struct pipe_buffer {
* @tmp_page: cached released page
* @readers: number of current readers of this pipe
* @writers: number of current writers of this pipe
+ * @files: number of struct file refering this pipe (protected by ->i_lock)
* @waiting_writers: number of writers blocked waiting for room
* @r_counter: reader counter
* @w_counter: writer counter
@@ -47,6 +48,7 @@ struct pipe_inode_info {
unsigned int nrbufs, curbuf, buffers;
unsigned int readers;
unsigned int writers;
+ unsigned int files;
unsigned int waiting_writers;
unsigned int r_counter;
unsigned int w_counter;