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

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: 3372de5 ("dmaengine: ioatdma: removal of dma_v3.c and relevant ioat3 references")
Signed-off-by: Dave Jiang <[email protected]>
Link: https://lore.kernel.org/r/166360672197.3851724.17040290563764838369.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <[email protected]>

Author: davejiang

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)