Re: [linux-dvb] [PATCH] 1/3: BUG FIX in dvb_ringbuffer_flush

[Andrea <mariofutire@googlemail.com>]

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Andrea wrote:
> linux-dvb-request@linuxtv.org wrote:
> I've added a new function in the ringbuffer that resets the pointers to 
> 0 and clears the error flag.
> There might be some more factoring and one could move into that function 
> 2 more lines
> 
>     buf->data = NULL;
>     buf->size = size;
>     dvb_ringbuffer_reset(buf);

I've just added a comment to patch 1/3.
I post it here again.

This patch fixes the bug in DMX_SET_BUFFER_SIZE for the demux.
Basically it resets read and write pointers to 0 in case they are beyond the new size of the buffer.

In the next patch (2/3) I rewrite this function to behave the same as the new DMX_SET_BUFFER_SIZE 
for the dvr.
I thought it is a good idea for the 2 very similar ioctl to be implemented in the same way.

Andrea

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diff -r 54cdcd915a6b linux/drivers/media/dvb/dvb-core/dmxdev.c
--- a/linux/drivers/media/dvb/dvb-core/dmxdev.c	Fri Apr 11 08:29:44 2008 -0300
+++ b/linux/drivers/media/dvb/dvb-core/dmxdev.c	Sun Apr 13 09:50:59 2008 +0100
@@ -281,7 +281,9 @@ static int dvb_dmxdev_set_buffer_size(st
 	mem = buf->data;
 	buf->data = NULL;
 	buf->size = size;
-	dvb_ringbuffer_flush(buf);
+	
+	// reset and not flush in case the buffer shrinks
+	dvb_ringbuffer_reset(buf);
 	spin_unlock_irq(&dmxdevfilter->dev->lock);
 	vfree(mem);
 
diff -r 54cdcd915a6b linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.c
--- a/linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.c	Fri Apr 11 08:29:44 2008 -0300
+++ b/linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.c	Sun Apr 13 09:50:59 2008 +0100
@@ -90,6 +90,11 @@ void dvb_ringbuffer_flush(struct dvb_rin
 	rbuf->error = 0;
 }
 
+void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf)
+{
+	rbuf->pread = rbuf->pwrite = 0;
+	rbuf->error = 0;
+}
 
 
 void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)
diff -r 54cdcd915a6b linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.h
--- a/linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.h	Fri Apr 11 08:29:44 2008 -0300
+++ b/linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.h	Sun Apr 13 09:50:59 2008 +0100
@@ -84,6 +84,12 @@ extern ssize_t dvb_ringbuffer_free(struc
 /* return the number of bytes waiting in the buffer */
 extern ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf);
 
+/* 
+** Reset the read and write pointers to zero and flush the buffer
+** This counts as a read and write operation
+*/
+
+extern void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf);
 
 /* read routines & macros */
 /* ---------------------- */

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