[PATCH] habanalabs: share a single ctx-mutex between all MMUs

Oded Gabbay
2020-11-14T09:25:08Z

From: Moti Haimovski <mhaimovski@habana.ai>

Multiple locks are usually a source of problems, which in the MMU
case can be avoided since it is relatively rare that both MMU
tables are updated at the same time.

Therefore, use a single shared lock instead of two separate ones.

Signed-off-by: Moti Haimovski <mhaimovski@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
---
drivers/misc/habanalabs/common/mmu.c | 4 ++++
drivers/misc/habanalabs/common/mmu_v1.c | 4 ----
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/habanalabs/common/mmu.c b/drivers/misc/habanalabs/common/mmu.c
index 6f535c81478d..f4b3d02fe0d8 100644
--- a/drivers/misc/habanalabs/common/mmu.c
+++ b/drivers/misc/habanalabs/common/mmu.c
@@ -81,6 +81,8 @@ int hl_mmu_ctx_init(struct hl_ctx *ctx)
if (!hdev->mmu_enable)
return 0;

+ mutex_init(&ctx->mmu_lock);
+
if (hdev->mmu_func[MMU_DR_PGT].ctx_init != NULL) {
rc = hdev->mmu_func[MMU_DR_PGT].ctx_init(ctx);
if (rc)
@@ -115,6 +117,8 @@ void hl_mmu_ctx_fini(struct hl_ctx *ctx)

if (hdev->mmu_func[MMU_HR_PGT].ctx_fini != NULL)
hdev->mmu_func[MMU_HR_PGT].ctx_fini(ctx);
+
+ mutex_destroy(&ctx->mmu_lock);
}

/*
diff --git a/drivers/misc/habanalabs/common/mmu_v1.c b/drivers/misc/habanalabs/common/mmu_v1.c
index 5f62cb158eef..92b22298bb5c 100644
--- a/drivers/misc/habanalabs/common/mmu_v1.c
+++ b/drivers/misc/habanalabs/common/mmu_v1.c
@@ -481,9 +481,7 @@ static void hl_mmu_v1_fini(struct hl_device *hdev)
*/
static int hl_mmu_v1_ctx_init(struct hl_ctx *ctx)
{
- mutex_init(&ctx->mmu_lock);
hash_init(ctx->mmu_shadow_hash);
-
return dram_default_mapping_init(ctx);
}

@@ -516,8 +514,6 @@ static void hl_mmu_v1_ctx_fini(struct hl_ctx *ctx)
pgt_info->phys_addr, ctx->asid, pgt_info->num_of_ptes);
_free_hop(ctx, pgt_info);
}
-
- mutex_destroy(&ctx->mmu_lock);
}

static int _hl_mmu_v1_unmap(struct hl_ctx *ctx,
--
2.17.1