IB/iser: Always check sig MR before putting it to the free pool

libiscsi calls the check_protection transport handler only if SCSI-Respose
is received. So, the handler is never called if iSCSI task is completed
for some other reason like a timeout or error handling. And this behavior
looks correct. But the iSER does not handle this case properly because it
puts a non-checked signature MR to the free pool. Then the error occurs at
reusing the MR because it is not allowed to invalidate a signature MR
without checking.

This commit adds an extra check to iser_unreg_mem_fastreg(), which is a
part of the task cleanup flow. Now the signature MR is checked there if it
is needed.

Link: https://lore.kernel.org/r/20200325151210.1548-1-sergeygo@mellanox.com
Signed-off-by: Sergey Gorenko <sergeygo@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/ulp/iser/iser_memory.c b/drivers/infiniband/ulp/iser/iser_memory.c
index 7a8f24de36319cb449e1b8b0195b8cc1ed8df385..999ef7cdd05e42a6896bfaf4d3a19ea68068ac59 100644 (file)
--- a/drivers/infiniband/ulp/iser/iser_memory.c
+++ b/drivers/infiniband/ulp/iser/iser_memory.c
@@ -292,12 +292,27 @@ void iser_unreg_mem_fastreg(struct iscsi_iser_task *iser_task,
 {
        struct iser_device *device = iser_task->iser_conn->ib_conn.device;
        struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];
+       struct iser_fr_desc *desc;
+       struct ib_mr_status mr_status;
 
-       if (!reg->mem_h)
+       desc = reg->mem_h;
+       if (!desc)
                return;
 
-       device->reg_ops->reg_desc_put(&iser_task->iser_conn->ib_conn,
-                                    reg->mem_h);
+       /*
+        * The signature MR cannot be invalidated and reused without checking.
+        * libiscsi calls the check_protection transport handler only if
+        * SCSI-Response is received. And the signature MR is not checked if
+        * the task is completed for some other reason like a timeout or error
+        * handling. That's why we must check the signature MR here before
+        * putting it to the free pool.
+        */
+       if (unlikely(desc->sig_protected)) {
+               desc->sig_protected = false;
+               ib_check_mr_status(desc->rsc.sig_mr, IB_MR_CHECK_SIG_STATUS,
+                                  &mr_status);
+       }
+       device->reg_ops->reg_desc_put(&iser_task->iser_conn->ib_conn, desc);
        reg->mem_h = NULL;
 }