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

[Andrea <mariofutire@googlemail.com>]

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linux-dvb-request@linuxtv.org wrote:
> Date: Sat, 22 Mar 2008 04:56:43 +0100
> From: Oliver Endriss <o.endriss@gmx.de>
> 
  > Nak. At the first glance one might think that this patch is correct.
  > Unfortunately, it introduces a subtle bug.

> So I suggest to leave dvb_ringbuffer_flush() as is and zero the read and
> write pointers only where it is really required...

Thanks for your feedback.
You are right and I have changed the code.

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);


Andrea


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diff -r 1886a5ea2f84 linux/drivers/media/dvb/dvb-core/dmxdev.c
--- a/linux/drivers/media/dvb/dvb-core/dmxdev.c	Fri Mar 21 08:04:55 2008 -0300
+++ b/linux/drivers/media/dvb/dvb-core/dmxdev.c	Sat Mar 22 10:12:59 2008 +0000
@@ -281,7 +313,7 @@ static int dvb_dmxdev_set_buffer_size(st
 	mem = buf->data;
 	buf->data = NULL;
 	buf->size = size;
-	dvb_ringbuffer_flush(buf);
+	dvb_ringbuffer_reset(buf);
 	spin_unlock_irq(&dmxdevfilter->dev->lock);
 	vfree(mem);
 
diff -r 1886a5ea2f84 linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.c
--- a/linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.c	Fri Mar 21 08:04:55 2008 -0300
+++ b/linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.c	Sat Mar 22 10:12:59 2008 +0000
@@ -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 1886a5ea2f84 linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.h
--- a/linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.h	Fri Mar 21 08:04:55 2008 -0300
+++ b/linux/drivers/media/dvb/dvb-core/dvb_ringbuffer.h	Sat Mar 22 10:12:59 2008 +0000
@@ -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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