Author: cem
Date: Wed Nov 30 21:59:52 2016
New Revision: 309338
URL: https://svnweb.freebsd.org/changeset/base/309338
Log:
ioat(4): Fix 'bogus completion_pending' KASSERT
Fix ioat_release to only set is_completion_pending if DMAs were actually
queued. Otherwise, the spurious flag could trigger an assert in the
reset path on INVARIANTS kernels.
Reviewed by: bdrewery, Suraj Raju @ Isilon
Sponsored by: Dell EMC Isilon
Modified:
head/sys/dev/ioat/ioat.c
head/sys/dev/ioat/ioat_internal.h
Modified: head/sys/dev/ioat/ioat.c
==============================================================================
--- head/sys/dev/ioat/ioat.c Wed Nov 30 21:53:06 2016 (r309337)
+++ head/sys/dev/ioat/ioat.c Wed Nov 30 21:59:52 2016 (r309338)
@@ -947,6 +947,7 @@ ioat_acquire(bus_dmaengine_t dmaengine)
ioat = to_ioat_softc(dmaengine);
mtx_lock(&ioat->submit_lock);
CTR2(KTR_IOAT, "%s channel=%u", __func__, ioat->chan_idx);
+ ioat->acq_head = ioat->head;
}
int
@@ -976,12 +977,15 @@ ioat_release(bus_dmaengine_t dmaengine)
CTR4(KTR_IOAT, "%s channel=%u dispatch2 hw_head=%u head=%u", __func__,
ioat->chan_idx, ioat->hw_head & UINT16_MAX, ioat->head);
- ioat_write_2(ioat, IOAT_DMACOUNT_OFFSET, (uint16_t)ioat->hw_head);
-
- if (!ioat->is_completion_pending) {
- ioat->is_completion_pending = TRUE;
- callout_reset(&ioat->poll_timer, 1, ioat_poll_timer_callback,
- ioat);
+ if (ioat->acq_head != ioat->head) {
+ ioat_write_2(ioat, IOAT_DMACOUNT_OFFSET,
+ (uint16_t)ioat->hw_head);
+
+ if (!ioat->is_completion_pending) {
+ ioat->is_completion_pending = TRUE;
+ callout_reset(&ioat->poll_timer, 1,
+ ioat_poll_timer_callback, ioat);
+ }
}
mtx_unlock(&ioat->submit_lock);
}
Modified: head/sys/dev/ioat/ioat_internal.h
==============================================================================
--- head/sys/dev/ioat/ioat_internal.h Wed Nov 30 21:53:06 2016
(r309337)
+++ head/sys/dev/ioat/ioat_internal.h Wed Nov 30 21:59:52 2016
(r309338)
@@ -483,6 +483,7 @@ struct ioat_softc {
boolean_t resetting_cleanup; /* cleanup_lock */
uint32_t head;
+ uint32_t acq_head;
uint32_t tail;
uint32_t hw_head;
uint32_t ring_size_order;
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