[PATCH] another round of fs/pipe.c cleanups
make pipe.c a bit more readable and hackable.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/fs/pipe.c b/fs/pipe.c
index b941e19..e984beb 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -44,7 +44,8 @@
* Pipes are system-local resources, so sleeping on them
* is considered a noninteractive wait:
*/
- prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE|TASK_NONINTERACTIVE);
+ prepare_to_wait(&pipe->wait, &wait,
+ TASK_INTERRUPTIBLE | TASK_NONINTERACTIVE);
if (pipe->inode)
mutex_unlock(&pipe->inode->i_mutex);
schedule();
@@ -93,7 +94,8 @@
return 0;
}
-static void anon_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
+static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
{
struct page *page = buf->page;
@@ -102,25 +104,22 @@
/*
* If nobody else uses this page, and we don't already have a
* temporary page, let's keep track of it as a one-deep
- * allocation cache
+ * allocation cache. (Otherwise just release our reference to it)
*/
- if (page_count(page) == 1 && !pipe->tmp_page) {
+ if (page_count(page) == 1 && !pipe->tmp_page)
pipe->tmp_page = page;
- return;
- }
-
- /*
- * Otherwise just release our reference to it
- */
- page_cache_release(page);
+ else
+ page_cache_release(page);
}
-static void *anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe, struct pipe_buffer *buf)
+static void * anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
{
return kmap(buf->page);
}
-static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
+static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
{
kunmap(buf->page);
}
@@ -182,7 +181,8 @@
error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars);
ops->unmap(pipe, buf);
if (unlikely(error)) {
- if (!ret) ret = -EFAULT;
+ if (!ret)
+ ret = -EFAULT;
break;
}
ret += chars;
@@ -218,7 +218,8 @@
}
}
if (signal_pending(current)) {
- if (!ret) ret = -ERESTARTSYS;
+ if (!ret)
+ ret = -ERESTARTSYS;
break;
}
if (do_wakeup) {
@@ -228,7 +229,8 @@
pipe_wait(pipe);
}
mutex_unlock(&inode->i_mutex);
- /* Signal writers asynchronously that there is more room. */
+
+ /* Signal writers asynchronously that there is more room. */
if (do_wakeup) {
wake_up_interruptible(&pipe->wait);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
@@ -242,6 +244,7 @@
pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
{
struct iovec iov = { .iov_base = buf, .iov_len = count };
+
return pipe_readv(filp, &iov, 1, ppos);
}
@@ -276,10 +279,12 @@
/* We try to merge small writes */
chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */
if (pipe->nrbufs && chars != 0) {
- int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) & (PIPE_BUFFERS-1);
+ int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) &
+ (PIPE_BUFFERS-1);
struct pipe_buffer *buf = pipe->bufs + lastbuf;
struct pipe_buf_operations *ops = buf->ops;
int offset = buf->offset + buf->len;
+
if (ops->can_merge && offset + chars <= PAGE_SIZE) {
void *addr;
int error;
@@ -306,9 +311,11 @@
for (;;) {
int bufs;
+
if (!pipe->readers) {
send_sig(SIGPIPE, current, 0);
- if (!ret) ret = -EPIPE;
+ if (!ret)
+ ret = -EPIPE;
break;
}
bufs = pipe->nrbufs;
@@ -326,7 +333,7 @@
}
pipe->tmp_page = page;
}
- /* Always wakeup, even if the copy fails. Otherwise
+ /* Always wake up, even if the copy fails. Otherwise
* we lock up (O_NONBLOCK-)readers that sleep due to
* syscall merging.
* FIXME! Is this really true?
@@ -339,7 +346,8 @@
error = pipe_iov_copy_from_user(kmap(page), iov, chars);
kunmap(page);
if (unlikely(error)) {
- if (!ret) ret = -EFAULT;
+ if (!ret)
+ ret = -EFAULT;
break;
}
ret += chars;
@@ -359,11 +367,13 @@
if (bufs < PIPE_BUFFERS)
continue;
if (filp->f_flags & O_NONBLOCK) {
- if (!ret) ret = -EAGAIN;
+ if (!ret)
+ ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
- if (!ret) ret = -ERESTARTSYS;
+ if (!ret)
+ ret = -ERESTARTSYS;
break;
}
if (do_wakeup) {
@@ -391,6 +401,7 @@
size_t count, loff_t *ppos)
{
struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
+
return pipe_writev(filp, &iov, 1, ppos);
}
@@ -401,7 +412,8 @@
}
static ssize_t
-bad_pipe_w(struct file *filp, const char __user *buf, size_t count, loff_t *ppos)
+bad_pipe_w(struct file *filp, const char __user *buf, size_t count,
+ loff_t *ppos)
{
return -EBADF;
}
@@ -475,6 +487,7 @@
pipe = inode->i_pipe;
pipe->readers -= decr;
pipe->writers -= decw;
+
if (!pipe->readers && !pipe->writers) {
free_pipe_info(inode);
} else {
@@ -525,14 +538,15 @@
pipe_rdwr_fasync(int fd, struct file *filp, int on)
{
struct inode *inode = filp->f_dentry->d_inode;
+ struct pipe_inode_info *pipe = inode->i_pipe;
int retval;
mutex_lock(&inode->i_mutex);
- retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers);
+ retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);
if (retval >= 0)
- retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers);
+ retval = fasync_helper(fd, filp, on, &pipe->fasync_writers);
mutex_unlock(&inode->i_mutex);
@@ -720,6 +734,7 @@
{
return 1;
}
+
static struct dentry_operations pipefs_dentry_operations = {
.d_delete = pipefs_delete_dentry,
};
@@ -757,6 +772,7 @@
fail_iput:
iput(inode);
+
fail_inode:
return NULL;
}
@@ -769,7 +785,7 @@
struct inode * inode;
struct file *f1, *f2;
int error;
- int i,j;
+ int i, j;
error = -ENFILE;
f1 = get_empty_filp();
@@ -802,6 +818,7 @@
dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this);
if (!dentry)
goto close_f12_inode_i_j;
+
dentry->d_op = &pipefs_dentry_operations;
d_add(dentry, inode);
f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt));
@@ -825,6 +842,7 @@
fd_install(j, f2);
fd[0] = i;
fd[1] = j;
+
return 0;
close_f12_inode_i_j:
@@ -849,8 +867,9 @@
* d_name - pipe: will go nicely and kill the special-casing in procfs.
*/
-static struct super_block *pipefs_get_sb(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data)
+static struct super_block *
+pipefs_get_sb(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data)
{
return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC);
}
@@ -864,6 +883,7 @@
static int __init init_pipe_fs(void)
{
int err = register_filesystem(&pipe_fs_type);
+
if (!err) {
pipe_mnt = kern_mount(&pipe_fs_type);
if (IS_ERR(pipe_mnt)) {