Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
To:     linux-rdma@vger.kernel.org, leonro@nvidia.com, jgg@nvidia.com,
        zyjzyj2000@gmail.com
Cc:     nvdimm@lists.linux.dev, linux-kernel@vger.kernel.org,
        rpearsonhpe@gmail.com, yangx.jy@fujitsu.com, lizhijian@fujitsu.com,
        y-goto@fujitsu.com, Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
Subject: [RFC PATCH v2 1/7] IB/mlx5: Change ib_umem_odp_map_dma_single_page() to retain umem_mutex
Date:   Fri, 11 Nov 2022 18:22:22 +0900
Message-Id: <b9974985069900c80b8ff9e6b0b0b346c1592910.1668157436.git.matsuda-daisuke@fujitsu.com>
In-Reply-To: <cover.1668157436.git.matsuda-daisuke@fujitsu.com>
References: <cover.1668157436.git.matsuda-daisuke@fujitsu.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

ib_umem_odp_map_dma_single_page(), which has been used only by the mlx5
driver, holds umem_mutex on success and releases on failure. This
behavior is not convenient for other drivers to use it, so change it to
always retain mutex on return.

Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
---
 drivers/infiniband/core/umem_odp.c | 8 +++-----
 drivers/infiniband/hw/mlx5/odp.c   | 4 +++-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
index e9fa22d31c23..49da6735f7c8 100644
--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -328,8 +328,8 @@ static int ib_umem_odp_map_dma_single_page(
  *
  * Maps the range passed in the argument to DMA addresses.
  * The DMA addresses of the mapped pages is updated in umem_odp->dma_list.
- * Upon success the ODP MR will be locked to let caller complete its device
- * page table update.
+ * The umem mutex is locked in this function. Callers are responsible for
+ * releasing the lock.
  *
  * Returns the number of pages mapped in success, negative error code
  * for failure.
@@ -453,11 +453,9 @@ int ib_umem_odp_map_dma_and_lock(struct ib_umem_odp *umem_odp, u64 user_virt,
 			break;
 		}
 	}
-	/* upon success lock should stay on hold for the callee */
+
 	if (!ret)
 		ret = dma_index - start_idx;
-	else
-		mutex_unlock(&umem_odp->umem_mutex);
 
 out_put_mm:
 	mmput_async(owning_mm);
diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index bc97958818bb..a0de27651586 100644
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -572,8 +572,10 @@ static int pagefault_real_mr(struct mlx5_ib_mr *mr, struct ib_umem_odp *odp,
 		access_mask |= ODP_WRITE_ALLOWED_BIT;
 
 	np = ib_umem_odp_map_dma_and_lock(odp, user_va, bcnt, access_mask, fault);
-	if (np < 0)
+	if (np < 0) {
+		mutex_unlock(&odp->umem_mutex);
 		return np;
+	}
 
 	/*
 	 * No need to check whether the MTTs really belong to this MR, since
-- 
2.31.1