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media: mantis: prevent staying forever in a loop at IRQ

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As warned by smatch:
	drivers/media/pci/mantis/mantis_uart.c:105 mantis_uart_work() warn: this loop depends on readl() succeeding

If something goes wrong at readl(), the logic will stay there
inside an IRQ code forever. This is not the nicest thing to
do :-)

So, add a timeout there, preventing staying inside the IRQ
for more than 10ms.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab 2018-04-12 08:28:33 -04:00
parent ee2d243d6b
commit cac61a1acb
1 changed files with 7 additions and 0 deletions
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7
drivers/media/pci/mantis/mantis_uart.c
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@ -92,6 +92,7 @@ static void mantis_uart_work(struct work_struct *work)
{
struct mantis_pci *mantis = container_of(work, struct mantis_pci, uart_work);
u32 stat;
unsigned long timeout;
stat = mmread(MANTIS_UART_STAT);
@ -102,9 +103,15 @@ static void mantis_uart_work(struct work_struct *work)
* MANTIS_UART_RXFIFO_DATA is only set if at least
* config->bytes + 1 bytes are in the FIFO.
*/
/* FIXME: is 10ms good enough ? */
timeout = jiffies + msecs_to_jiffies(10);
while (stat & MANTIS_UART_RXFIFO_DATA) {
mantis_uart_read(mantis);
stat = mmread(MANTIS_UART_STAT);
if (!time_is_after_jiffies(timeout))
break;
}
/* re-enable UART (RX) interrupt */