[PATCH] pipe: remove redundant fifo_poll abstraction

[Pekka Enberg <penberg@cs.helsinki.fi>]

On Fri, 2005-08-26 at 19:16 +0200, Manfred Spraul wrote:
> I would prefer just to remove the abstraction, together with a comment 
> that Linux fifos behave exactly like pipes, unlike the behavior of most 
> unices.

[PATCH] pipe: remove redundant fifo_poll abstraction

This patch removes a redundant fifo_poll() abstraction from fs/pipe.c and adds
a big fat comment stating we set POLLERR for FIFOs too on Linux unlike most
Unices.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---

 pipe.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

Index: 2.6-mm/fs/pipe.c
===================================================================
--- 2.6-mm.orig/fs/pipe.c
+++ 2.6-mm/fs/pipe.c
@@ -419,6 +419,10 @@ pipe_poll(struct file *filp, poll_table 
 
 	if (filp->f_mode & FMODE_WRITE) {
 		mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0;
+		/*
+		 * Most Unices do not set POLLERR for FIFOs but on Linux they
+		 * behave exactly like pipes for poll().
+		 */
 		if (!PIPE_READERS(*inode))
 			mask |= POLLERR;
 	}
@@ -426,9 +430,6 @@ pipe_poll(struct file *filp, poll_table 
 	return mask;
 }
 
-/* FIXME: most Unices do not set POLLERR for fifos */
-#define fifo_poll pipe_poll
-
 static int
 pipe_release(struct inode *inode, int decr, int decw)
 {
@@ -572,7 +573,7 @@ struct file_operations read_fifo_fops = 
 	.read		= pipe_read,
 	.readv		= pipe_readv,
 	.write		= bad_pipe_w,
-	.poll		= fifo_poll,
+	.poll		= pipe_poll,
 	.ioctl		= pipe_ioctl,
 	.open		= pipe_read_open,
 	.release	= pipe_read_release,
@@ -584,7 +585,7 @@ struct file_operations write_fifo_fops =
 	.read		= bad_pipe_r,
 	.write		= pipe_write,
 	.writev		= pipe_writev,
-	.poll		= fifo_poll,
+	.poll		= pipe_poll,
 	.ioctl		= pipe_ioctl,
 	.open		= pipe_write_open,
 	.release	= pipe_write_release,
@@ -597,7 +598,7 @@ struct file_operations rdwr_fifo_fops = 
 	.readv		= pipe_readv,
 	.write		= pipe_write,
 	.writev		= pipe_writev,
-	.poll		= fifo_poll,
+	.poll		= pipe_poll,
 	.ioctl		= pipe_ioctl,
 	.open		= pipe_rdwr_open,
 	.release	= pipe_rdwr_release,


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