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V4L/DVB (7563): em28xx: Add missing checks 

There are some cases where nobody is waiting for a buffer. Due to the
lack of check, if you try to abort the userspace app, machine were
hanging, since IRQ were trying to use a buffer that were disallocated.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Mauro Carvalho Chehab 2008-04-13 15:08:55 -03:00
parent 0cf4daee31
commit dbecb44c11
1 changed files with 26 additions and 9 deletions
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35
drivers/media/video/em28xx/em28xx-video.c
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@ -270,19 +270,39 @@ static inline int get_next_buf(struct em28xx_dmaqueue *dma_q,
struct em28xx_buffer **buf)
{
struct em28xx *dev = container_of(dma_q, struct em28xx, vidq);
char *outp;
/* If the previous buffer were not filled yet, continue */
if (list_empty(&dma_q->active)) {
em28xx_isocdbg("No active queue to serve\n");
dev->isoc_ctl.buf = NULL;
return 0;
}
/* Check if the last buffer were fully filled */
*buf = dev->isoc_ctl.buf;
/* Nobody is waiting on this buffer - discards */
if (*buf && !waitqueue_active(&(*buf)->vb.done)) {
dev->isoc_ctl.buf = NULL;
*buf = NULL;
}
/* Returns the last buffer, to be filled with remaining data */
if (*buf)
return 1;
if (list_empty(&dma_q->active)) {
/* Get the next buffer */
*buf = list_entry(dma_q->active.next, struct em28xx_buffer, vb.queue);
/* Nobody is waiting on the next buffer. returns */
if (!*buf || !waitqueue_active(&(*buf)->vb.done)) {
em28xx_isocdbg("No active queue to serve\n");
return 0;
}
*buf = list_entry(dma_q->active.next, struct em28xx_buffer, vb.queue);
/* Cleans up buffer - Usefull for testing for frame/URB loss */
outp = videobuf_to_vmalloc(&(*buf)->vb);
memset(outp, 0, (*buf)->vb.size);
dev->isoc_ctl.buf = *buf;
@ -387,12 +407,11 @@ static void em28xx_irq_callback(struct urb *urb)
struct em28xx_dmaqueue *dma_q = urb->context;
struct em28xx *dev = container_of(dma_q, struct em28xx, vidq);
int rc, i;
unsigned long flags;
spin_lock_irqsave(&dev->slock, flags);
/* Copy data from URB */
spin_lock(&dev->slock);
rc = em28xx_isoc_copy(urb);
spin_unlock(&dev->slock);
/* Reset urb buffers */
for (i = 0; i < urb->number_of_packets; i++) {
@ -406,8 +425,6 @@ static void em28xx_irq_callback(struct urb *urb)
em28xx_err("urb resubmit failed (error=%i)\n",
urb->status);
}
spin_unlock_irqrestore(&dev->slock, flags);
}
/*