Re: [PATCH v2 3/3] dmaengine: ioat: adding missed issue_pending to timeout handler

From: Dave Jiang
Date: Wed Apr 22 2020 - 15:58:25 EST




On 4/22/2020 12:25 PM, leonid.ravich@xxxxxxxx wrote:
From: Leonid Ravich <Leonid.Ravich@xxxxxxx>

completion timeout might trigger unnesesery DMA engine hw reboot
in case of missed issue_pending() .

Acked-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Signed-off-by: Leonid Ravich <Leonid.Ravich@xxxxxxx>
---
Changing in v2
- add log in case of such scenario
drivers/dma/ioat/dma.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 55a8cf1..a958aaf 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -955,6 +955,14 @@ void ioat_timer_event(struct timer_list *t)
goto unlock_out;
}
+ /* handle missed issue pending case */
+ if (ioat_ring_pending(ioat_chan)) {
+ dev_dbg(to_dev(ioat_chan), "Complition timeout while pending\n")
Completion timeout with pending descriptors.

Also, maybe dev_warn() you think?

+ spin_lock_bh(&ioat_chan->prep_lock);
+ __ioat_issue_pending(ioat_chan);
+ spin_unlock_bh(&ioat_chan->prep_lock);
+ }
+
set_bit(IOAT_COMPLETION_ACK, &ioat_chan->state);
mod_timer(&ioat_chan->timer, jiffies + COMPLETION_TIMEOUT);
unlock_out: