[PATCH] dmaengine: ioat: stop mod_timer from resurrecting deleted timer in __cleanup()

[PATCH] dmaengine: ioat: stop mod_timer from resurrecting deleted timer in __cleanup()

[Dave Jiang]

User reports observing timer event report channel halted but no error
observed in CHANERR register. The driver finished self-test and released
channel resources. Debug shows that __cleanup() can call
mod_timer() after the timer has been deleted and thus resurrect the
timer. While harmless, it causes suprious error message to be emitted.
Use mod_timer_pending() call to prevent deleted timer from being
resurrected.

Fixes: 3372de5813e4 ("dmaengine: ioatdma: removal of dma_v3.c and relevant ioat3 references")
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/dma/ioat/dma.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 37ff4ec7db76..e2070df6cad2 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -656,7 +656,7 @@ static void __cleanup(struct ioatdma_chan *ioat_chan, dma_addr_t phys_complete)
 	if (active - i == 0) {
 		dev_dbg(to_dev(ioat_chan), "%s: cancel completion timeout\n",
 			__func__);
-		mod_timer(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);
+		mod_timer_pending(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);
 	}
 
 	/* microsecond delay by sysfs variable  per pending descriptor */
@@ -682,7 +682,7 @@ static void ioat_cleanup(struct ioatdma_chan *ioat_chan)
 
 		if (chanerr &
 		    (IOAT_CHANERR_HANDLE_MASK | IOAT_CHANERR_RECOVER_MASK)) {
-			mod_timer(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);
+			mod_timer_pending(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);
 			ioat_eh(ioat_chan);
 		}
 	}
@@ -879,7 +879,7 @@ static void check_active(struct ioatdma_chan *ioat_chan)
 	}
 
 	if (test_and_clear_bit(IOAT_CHAN_ACTIVE, &ioat_chan->state))
-		mod_timer(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);
+		mod_timer_pending(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);
 }
 
 static void ioat_reboot_chan(struct ioatdma_chan *ioat_chan)

Re: [PATCH] dmaengine: ioat: stop mod_timer from resurrecting deleted timer in __cleanup()

[Vinod Koul]

On 19-09-22, 09:58, Dave Jiang wrote:
> User reports observing timer event report channel halted but no error
> observed in CHANERR register. The driver finished self-test and released
> channel resources. Debug shows that __cleanup() can call
> mod_timer() after the timer has been deleted and thus resurrect the
> timer. While harmless, it causes suprious error message to be emitted.
> Use mod_timer_pending() call to prevent deleted timer from being
> resurrected.

Applied, thanks

-- 
~Vinod