From cac61a1acb1def146c3900f1c8f7af4947d98814 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Thu, 12 Apr 2018 08:28:33 -0400 Subject: [PATCH] media: mantis: prevent staying forever in a loop at IRQ 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 --- drivers/media/pci/mantis/mantis_uart.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/media/pci/mantis/mantis_uart.c b/drivers/media/pci/mantis/mantis_uart.c index 18f81c1..b776568 100644 --- a/drivers/media/pci/mantis/mantis_uart.c +++ b/drivers/media/pci/mantis/mantis_uart.c @@ -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 */ -- 2.7.4