splice: add helpers for locking pipe inode
There are lots of sequences like this, especially in splice code:
if (pipe->inode)
mutex_lock(&pipe->inode->i_mutex);
/* do something */
if (pipe->inode)
mutex_unlock(&pipe->inode->i_mutex);
so introduce helpers which do the conditional locking and unlocking.
Also replace the inode_double_lock() call with a pipe_double_lock()
helper to avoid spreading the use of this functionality beyond the
pipe code.
This patch is just a cleanup, and should cause no behavioral changes.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fs/splice.c b/fs/splice.c
index 128ee36..5384a90 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -182,8 +182,7 @@
do_wakeup = 0;
page_nr = 0;
- if (pipe->inode)
- mutex_lock(&pipe->inode->i_mutex);
+ pipe_lock(pipe);
for (;;) {
if (!pipe->readers) {
@@ -245,15 +244,13 @@
pipe->waiting_writers--;
}
- if (pipe->inode) {
- mutex_unlock(&pipe->inode->i_mutex);
+ pipe_unlock(pipe);
- if (do_wakeup) {
- smp_mb();
- if (waitqueue_active(&pipe->wait))
- wake_up_interruptible(&pipe->wait);
- kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
- }
+ if (do_wakeup) {
+ smp_mb();
+ if (waitqueue_active(&pipe->wait))
+ wake_up_interruptible(&pipe->wait);
+ kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
}
while (page_nr < spd_pages)
@@ -801,11 +798,9 @@
.u.file = out,
};
- if (pipe->inode)
- mutex_lock(&pipe->inode->i_mutex);
+ pipe_lock(pipe);
ret = __splice_from_pipe(pipe, &sd, actor);
- if (pipe->inode)
- mutex_unlock(&pipe->inode->i_mutex);
+ pipe_unlock(pipe);
return ret;
}
@@ -837,8 +832,7 @@
};
ssize_t ret;
- if (pipe->inode)
- mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_PARENT);
+ pipe_lock(pipe);
splice_from_pipe_begin(&sd);
do {
@@ -854,8 +848,7 @@
} while (ret > 0);
splice_from_pipe_end(pipe, &sd);
- if (pipe->inode)
- mutex_unlock(&pipe->inode->i_mutex);
+ pipe_unlock(pipe);
if (sd.num_spliced)
ret = sd.num_spliced;
@@ -1348,8 +1341,7 @@
if (!pipe)
return -EBADF;
- if (pipe->inode)
- mutex_lock(&pipe->inode->i_mutex);
+ pipe_lock(pipe);
error = ret = 0;
while (nr_segs) {
@@ -1404,8 +1396,7 @@
iov++;
}
- if (pipe->inode)
- mutex_unlock(&pipe->inode->i_mutex);
+ pipe_unlock(pipe);
if (!ret)
ret = error;
@@ -1533,7 +1524,7 @@
return 0;
ret = 0;
- mutex_lock(&pipe->inode->i_mutex);
+ pipe_lock(pipe);
while (!pipe->nrbufs) {
if (signal_pending(current)) {
@@ -1551,7 +1542,7 @@
pipe_wait(pipe);
}
- mutex_unlock(&pipe->inode->i_mutex);
+ pipe_unlock(pipe);
return ret;
}
@@ -1571,7 +1562,7 @@
return 0;
ret = 0;
- mutex_lock(&pipe->inode->i_mutex);
+ pipe_lock(pipe);
while (pipe->nrbufs >= PIPE_BUFFERS) {
if (!pipe->readers) {
@@ -1592,7 +1583,7 @@
pipe->waiting_writers--;
}
- mutex_unlock(&pipe->inode->i_mutex);
+ pipe_unlock(pipe);
return ret;
}
@@ -1608,10 +1599,10 @@
/*
* Potential ABBA deadlock, work around it by ordering lock
- * grabbing by inode address. Otherwise two different processes
+ * grabbing by pipe info address. Otherwise two different processes
* could deadlock (one doing tee from A -> B, the other from B -> A).
*/
- inode_double_lock(ipipe->inode, opipe->inode);
+ pipe_double_lock(ipipe, opipe);
do {
if (!opipe->readers) {
@@ -1662,7 +1653,8 @@
if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK))
ret = -EAGAIN;
- inode_double_unlock(ipipe->inode, opipe->inode);
+ pipe_unlock(ipipe);
+ pipe_unlock(opipe);
/*
* If we put data in the output pipe, wakeup any potential readers.