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[PATCH] introduce a "kernel-internal pipe object" abstraction

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separate out the 'internal pipe object' abstraction, and make it
usable to splice. This cleans up and fixes several aspects of the
internal splice APIs and the pipe code:

 - pipes: the allocation and freeing of pipe_inode_info is now more symmetric
   and more streamlined with existing kernel practices.

 - splice: small micro-optimization: less pointer dereferencing in splice
   methods

Signed-off-by: Ingo Molnar <[email protected]>

Update XFS for the ->splice_read/->splice_write changes.

Signed-off-by: Jens Axboe <[email protected]>
This commit is contained in:
Ingo Molnar 2006-04-10 15:18:35 +02:00 • committed by Jens Axboe
commit 3a326a2ce8
9 changed files with 114 additions and 106 deletions
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51
fs/pipe.c
View file

@ -36,7 +36,7 @@
*/
/* Drop the inode semaphore and wait for a pipe event, atomically */
void pipe_wait(struct inode * inode)
void pipe_wait(struct pipe_inode_info *pipe)
{
DEFINE_WAIT(wait);
@ -44,11 +44,13 @@ void pipe_wait(struct inode * inode)
* Pipes are system-local resources, so sleeping on them
* is considered a noninteractive wait:
*/
prepare_to_wait(PIPE_WAIT(*inode), &wait, TASK_INTERRUPTIBLE|TASK_NONINTERACTIVE);
mutex_unlock(PIPE_MUTEX(*inode));
prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE|TASK_NONINTERACTIVE);
if (pipe->inode)
mutex_unlock(&pipe->inode->i_mutex);
schedule();
finish_wait(PIPE_WAIT(*inode), &wait);
mutex_lock(PIPE_MUTEX(*inode));
finish_wait(&pipe->wait, &wait);
if (pipe->inode)
mutex_lock(&pipe->inode->i_mutex);
}
static int
@ -223,7 +225,7 @@ pipe_readv(struct file *filp, const struct iovec *_iov,
wake_up_interruptible_sync(PIPE_WAIT(*inode));
kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT);
}
pipe_wait(inode);
pipe_wait(inode->i_pipe);
}
mutex_unlock(PIPE_MUTEX(*inode));
/* Signal writers asynchronously that there is more room. */
@ -370,7 +372,7 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
do_wakeup = 0;
}
PIPE_WAITING_WRITERS(*inode)++;
pipe_wait(inode);
pipe_wait(inode->i_pipe);
PIPE_WAITING_WRITERS(*inode)--;
}
out:
@ -675,6 +677,20 @@ static struct file_operations rdwr_pipe_fops = {
.fasync = pipe_rdwr_fasync,
};
struct pipe_inode_info * alloc_pipe_info(struct inode *inode)
{
struct pipe_inode_info *info;
info = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL);
if (info) {
init_waitqueue_head(&info->wait);
info->r_counter = info->w_counter = 1;
info->inode = inode;
}
return info;
}
void free_pipe_info(struct inode *inode)
{
int i;
@ -691,23 +707,6 @@ void free_pipe_info(struct inode *inode)
kfree(info);
}
struct inode* pipe_new(struct inode* inode)
{
struct pipe_inode_info *info;
info = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL);
if (!info)
goto fail_page;
inode->i_pipe = info;
init_waitqueue_head(PIPE_WAIT(*inode));
PIPE_RCOUNTER(*inode) = PIPE_WCOUNTER(*inode) = 1;
return inode;
fail_page:
return NULL;
}
static struct vfsmount *pipe_mnt __read_mostly;
static int pipefs_delete_dentry(struct dentry *dentry)
{
@ -724,8 +723,10 @@ static struct inode * get_pipe_inode(void)
if (!inode)
goto fail_inode;
if(!pipe_new(inode))
inode->i_pipe = alloc_pipe_info(inode);
if (!inode->i_pipe)
goto fail_iput;
PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 1;
inode->i_fop = &rdwr_pipe_fops;