From deb57fb237c3be9629a39ef1978dfac4563d6bda Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Mon, 20 Nov 2017 09:52:04 -0500 Subject: [PATCH] freedreno: proper locking for iterating dependent batches In transfer_map(), when we need to flush batches that read from a resource, we should be holding screen->lock to guard against race conditions. Somehow deferred flush seems to make this existing race more obvious. Signed-off-by: Rob Clark --- .../drivers/freedreno/freedreno_batch.h | 2 +- .../drivers/freedreno/freedreno_resource.c | 26 ++++++++++++++----- 2 files changed, 20 insertions(+), 8 deletions(-) diff --git a/src/gallium/drivers/freedreno/freedreno_batch.h b/src/gallium/drivers/freedreno/freedreno_batch.h index 41356e3519f..8b05f0657aa 100644 --- a/src/gallium/drivers/freedreno/freedreno_batch.h +++ b/src/gallium/drivers/freedreno/freedreno_batch.h @@ -66,7 +66,7 @@ struct fd_hw_sample; struct fd_batch { struct pipe_reference reference; unsigned seqno; - unsigned idx; + unsigned idx; /* index into cache->batches[] */ int in_fence_fd; bool needs_out_fence_fd; diff --git a/src/gallium/drivers/freedreno/freedreno_resource.c b/src/gallium/drivers/freedreno/freedreno_resource.c index 880666d3af5..e305b5f9eb8 100644 --- a/src/gallium/drivers/freedreno/freedreno_resource.c +++ b/src/gallium/drivers/freedreno/freedreno_resource.c @@ -531,14 +531,26 @@ fd_resource_transfer_map(struct pipe_context *pctx, if (needs_flush) { if (usage & PIPE_TRANSFER_WRITE) { - struct fd_batch *batch, *last_batch = NULL; - foreach_batch(batch, &ctx->screen->batch_cache, rsc->batch_mask) { - fd_batch_reference(&last_batch, batch); + struct fd_batch *batch, *batches[32] = {0}; + uint32_t batch_mask; + + /* This is a bit awkward, probably a fd_batch_flush_locked() + * would make things simpler.. but we need to hold the lock + * to iterate the batches which reference this resource. So + * we must first grab references under a lock, then flush. + */ + mtx_lock(&ctx->screen->lock); + batch_mask = rsc->batch_mask; + foreach_batch(batch, &ctx->screen->batch_cache, batch_mask) + fd_batch_reference(&batches[batch->idx], batch); + mtx_unlock(&ctx->screen->lock); + + foreach_batch(batch, &ctx->screen->batch_cache, batch_mask) fd_batch_flush(batch, false); - } - if (last_batch) { - fd_batch_sync(last_batch); - fd_batch_reference(&last_batch, NULL); + + foreach_batch(batch, &ctx->screen->batch_cache, batch_mask) { + fd_batch_sync(batch); + fd_batch_reference(&batches[batch->idx], NULL); } assert(rsc->batch_mask == 0); } else {