From 86ed09250e068faa840dadcd175d3cd8d174f998 Mon Sep 17 00:00:00 2001 From: Matthew Auld Date: Mon, 10 Jul 2023 10:40:40 +0100 Subject: [PATCH] drm/xe/tlb: ensure we access seqno_recv once MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Ensure we load gt->tlb_invalidation.seqno_recv once, and use that for our seqno checking. The gt->tlb_invalidation_seqno_past is a shared global variable and can potentially change at any point here. However the checks here need to operate on a stable version of seqno_recv for this to make any sense. Signed-off-by: Matthew Auld Cc: Matthew Brost Cc: José Roberto de Souza Reviewed-by: Matthew Brost Signed-off-by: Rodrigo Vivi --- drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c index 48eb05f763e9..2b60251ea1c0 100644 --- a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c +++ b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c @@ -257,15 +257,15 @@ int xe_gt_tlb_invalidation_vma(struct xe_gt *gt, static bool tlb_invalidation_seqno_past(struct xe_gt *gt, int seqno) { - if (seqno - gt->tlb_invalidation.seqno_recv < - -(TLB_INVALIDATION_SEQNO_MAX / 2)) + int seqno_recv = READ_ONCE(gt->tlb_invalidation.seqno_recv); + + if (seqno - seqno_recv < -(TLB_INVALIDATION_SEQNO_MAX / 2)) return false; - if (seqno - gt->tlb_invalidation.seqno_recv > - (TLB_INVALIDATION_SEQNO_MAX / 2)) + if (seqno - seqno_recv > (TLB_INVALIDATION_SEQNO_MAX / 2)) return true; - return gt->tlb_invalidation.seqno_recv >= seqno; + return seqno_recv >= seqno; } /** @@ -337,7 +337,7 @@ int xe_guc_tlb_invalidation_done_handler(struct xe_guc *guc, u32 *msg, u32 len) * wake_up_all() and wait_event_timeout() already have the correct * barriers. */ - gt->tlb_invalidation.seqno_recv = msg[0]; + WRITE_ONCE(gt->tlb_invalidation.seqno_recv, msg[0]); wake_up_all(&guc->ct.wq); fence = list_first_entry_or_null(>->tlb_invalidation.pending_fences, -- 2.39.5