[PATCH 4.2 125/134] IB/iser: Fix possible bogus DMA unmapping

Greg Kroah-Hartman
2015-09-26T22:00:12Z

From: Sagi Grimberg <sagig@mellanox.com>

commit 8d5944d80359e645feb2ebd069a6f4caf7825e40 upstream.

If iser_initialize_task_headers() routine failed before
dma mapping, we should not attempt to unmap in cleanup_task().

Fixes: 7414dde0a6c3a958e (IB/iser: Fix race between iser connection ...)
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/ulp/iser/iscsi_iser.c | 12 ++++++++----
drivers/infiniband/ulp/iser/iscsi_iser.h | 2 ++
2 files changed, 10 insertions(+), 4 deletions(-)

--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -201,6 +201,7 @@ iser_initialize_task_headers(struct iscs
goto out;
}

+ tx_desc->mapped = true;
tx_desc->dma_addr = dma_addr;
tx_desc->tx_sg[0].addr = tx_desc->dma_addr;
tx_desc->tx_sg[0].length = ISER_HEADERS_LEN;
@@ -360,16 +361,19 @@ iscsi_iser_task_xmit(struct iscsi_task *
static void iscsi_iser_cleanup_task(struct iscsi_task *task)
{
struct iscsi_iser_task *iser_task = task->dd_data;
- struct iser_tx_desc *tx_desc = &iser_task->desc;
- struct iser_conn *iser_conn = task->conn->dd_data;
+ struct iser_tx_desc *tx_desc = &iser_task->desc;
+ struct iser_conn *iser_conn = task->conn->dd_data;
struct iser_device *device = iser_conn->ib_conn.device;

/* DEVICE_REMOVAL event might have already released the device */
if (!device)
return;

- ib_dma_unmap_single(device->ib_device,
- tx_desc->dma_addr, ISER_HEADERS_LEN, DMA_TO_DEVICE);
+ if (likely(tx_desc->mapped)) {
+ ib_dma_unmap_single(device->ib_device, tx_desc->dma_addr,
+ ISER_HEADERS_LEN, DMA_TO_DEVICE);
+ tx_desc->mapped = false;
+ }

/* mgmt tasks do not need special cleanup */
if (!task->sc)
--- a/drivers/infiniband/ulp/iser/iscsi_iser.h
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.h
@@ -270,6 +270,7 @@ enum iser_desc_type {
* sg[1] optionally points to either of immediate data
* unsolicited data-out or control
* @num_sge: number sges used on this TX task
+ * @mapped: Is the task header mapped
*/
struct iser_tx_desc {
struct iser_hdr iser_header;
@@ -278,6 +279,7 @@ struct iser_tx_desc {
u64 dma_addr;
struct ib_sge tx_sg[2];
int num_sge;
+ bool mapped;
};

#define ISER_RX_PAD_SIZE (256 - (ISER_RX_PAYLOAD_SIZE + \