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drm/xe/tlb: drop unnecessary smp_wmb()

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wake_up_all() and wait_event_timeout() already have the correct barriers
as per https://www.kernel.org/doc/Documentation/memory-barriers.txt.
This should ensure that the seqno_recv write can't be re-ordered wrt to
the actual wake_up_all() i.e we get woken up but there is no write.  The
reader side with wait_event_timeout() also has the correct barriers.
With that drop the hand rolled smp_wmb(), which is anyway missing some
kind of matching barrier on the reader side.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
This commit is contained in:
Matthew Auld 2023-07-10 10:40:39 +01:00 committed by Rodrigo Vivi
parent b06d47be7c
commit 38fa29dc2b
1 changed files with 4 additions and 1 deletions
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5
drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
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@ -333,8 +333,11 @@ int xe_guc_tlb_invalidation_done_handler(struct xe_guc *guc, u32 *msg, u32 len)
expected_seqno, msg[0]);
}
/*
* wake_up_all() and wait_event_timeout() already have the correct
* barriers.
*/
gt->tlb_invalidation.seqno_recv = msg[0];
smp_wmb();
wake_up_all(&guc->ct.wq);
fence = list_first_entry_or_null(&gt->tlb_invalidation.pending_fences,