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pipe: preparation to new locking rules 

* use the fact that file_inode(file)->i_pipe doesn't change
  while the file is opened - no locks needed to access that.
* switch to pipe_lock/pipe_unlock where it's easy to do

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2013-03-21 02:16:30 -04:00
parent fc7478a2bf
commit 18c03cfd40
1 changed files with 15 additions and 23 deletions
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38
fs/pipe.c
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@ -363,8 +363,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
unsigned long nr_segs, loff_t pos)
{
struct file *filp = iocb->ki_filp;
struct inode *inode = file_inode(filp);
struct pipe_inode_info *pipe;
struct pipe_inode_info *pipe = file_inode(filp)->i_pipe;
int do_wakeup;
ssize_t ret;
struct iovec *iov = (struct iovec *)_iov;
@ -377,8 +376,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
do_wakeup = 0;
ret = 0;
mutex_lock(&inode->i_mutex);
pipe = inode->i_pipe;
pipe_lock(pipe);
for (;;) {
int bufs = pipe->nrbufs;
if (bufs) {
@ -466,7 +464,7 @@ redo:
}
pipe_wait(pipe);
}
mutex_unlock(&inode->i_mutex);
pipe_unlock(pipe);
/* Signal writers asynchronously that there is more room. */
if (do_wakeup) {
@ -488,8 +486,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
unsigned long nr_segs, loff_t ppos)
{
struct file *filp = iocb->ki_filp;
struct inode *inode = file_inode(filp);
struct pipe_inode_info *pipe;
struct pipe_inode_info *pipe = file_inode(filp)->i_pipe;
ssize_t ret;
int do_wakeup;
struct iovec *iov = (struct iovec *)_iov;
@ -503,8 +500,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
do_wakeup = 0;
ret = 0;
mutex_lock(&inode->i_mutex);
pipe = inode->i_pipe;
pipe_lock(pipe);
if (!pipe->readers) {
send_sig(SIGPIPE, current, 0);
@ -651,7 +647,7 @@ redo2:
pipe->waiting_writers--;
}
out:
mutex_unlock(&inode->i_mutex);
pipe_unlock(pipe);
if (do_wakeup) {
wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
@ -666,14 +662,12 @@ out:
static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
struct pipe_inode_info *pipe;
struct pipe_inode_info *pipe = file_inode(filp)->i_pipe;
int count, buf, nrbufs;
switch (cmd) {
case FIONREAD:
mutex_lock(&inode->i_mutex);
pipe = inode->i_pipe;
pipe_lock(pipe);
count = 0;
buf = pipe->curbuf;
nrbufs = pipe->nrbufs;
@ -681,7 +675,7 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
count += pipe->bufs[buf].len;
buf = (buf+1) & (pipe->buffers - 1);
}
mutex_unlock(&inode->i_mutex);
pipe_unlock(pipe);
return put_user(count, (int __user *)arg);
default:
@ -694,8 +688,7 @@ static unsigned int
pipe_poll(struct file *filp, poll_table *wait)
{
unsigned int mask;
struct inode *inode = file_inode(filp);
struct pipe_inode_info *pipe = inode->i_pipe;
struct pipe_inode_info *pipe = file_inode(filp)->i_pipe;
int nrbufs;
poll_wait(filp, &pipe->wait, wait);
@ -749,11 +742,10 @@ pipe_release(struct inode *inode, struct file *file)
static int
pipe_fasync(int fd, struct file *filp, int on)
{
struct inode *inode = file_inode(filp);
struct pipe_inode_info *pipe = inode->i_pipe;
struct pipe_inode_info *pipe = file_inode(filp)->i_pipe;
int retval = 0;
mutex_lock(&inode->i_mutex);
pipe_lock(pipe);
if (filp->f_mode & FMODE_READ)
retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);
if ((filp->f_mode & FMODE_WRITE) && retval >= 0) {
@ -762,7 +754,7 @@ pipe_fasync(int fd, struct file *filp, int on)
/* this can happen only if on == T */
fasync_helper(-1, filp, 0, &pipe->fasync_readers);
}
mutex_unlock(&inode->i_mutex);
pipe_unlock(pipe);
return retval;
}
@ -1224,7 +1216,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
if (!pipe)
return -EBADF;
mutex_lock(&pipe->inode->i_mutex);
pipe_lock(pipe);
switch (cmd) {
case F_SETPIPE_SZ: {
@ -1253,7 +1245,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
}
out:
mutex_unlock(&pipe->inode->i_mutex);
pipe_unlock(pipe);
return ret;
}