[PATCH AUTOSEL for 4.9 174/190] iser-target: avoid reinitializing rdma contexts for isert commands

[Sasha Levin]

From: Bharat Potnuri <bha...@chelsio.com>

[ Upstream commit 66f53e6f5400578bae58db0c06d85a8820831f40 ]

isert commands that failed during isert_rdma_rw_ctx_post() are queued to
Queue-Full(QF) queue and are scheduled to be reposted during queue-full
queue processing. During this reposting, the rdma contexts are initialised
again in isert_rdma_rw_ctx_post(), which is leaking significant memory.

unreferenced object 0xffff8830201d9640 (size 64):
  comm "kworker/0:2", pid 195, jiffies 4295374851 (age 4528.436s)
  hex dump (first 32 bytes):
    00 60 8b cb 2e 00 00 00 00 10 00 00 00 00 00 00  .`..............
    00 90 e3 cb 2e 00 00 00 00 10 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8170711e>] kmemleak_alloc+0x4e/0xb0
    [<ffffffff811f8ba5>] __kmalloc+0x125/0x2b0
    [<ffffffffa046b24f>] rdma_rw_ctx_init+0x15f/0x6f0 [ib_core]
    [<ffffffffa07ab644>] isert_rdma_rw_ctx_post+0xc4/0x3c0 [ib_isert]
    [<ffffffffa07ad972>] isert_put_datain+0x112/0x1c0 [ib_isert]
    [<ffffffffa07dddce>] lio_queue_data_in+0x2e/0x30 [iscsi_target_mod]
    [<ffffffffa076c322>] target_qf_do_work+0x2b2/0x4b0 [target_core_mod]
    [<ffffffff81080c3b>] process_one_work+0x1db/0x5d0
    [<ffffffff8108107d>] worker_thread+0x4d/0x3e0
    [<ffffffff81088667>] kthread+0x117/0x150
    [<ffffffff81713fa7>] ret_from_fork+0x27/0x40
    [<ffffffffffffffff>] 0xffffffffffffffff

Here is patch to use the older rdma contexts while reposting
the isert commands intead of reinitialising them.

Signed-off-by: Potnuri Bharat Teja <bha...@chelsio.com>
Reviewed-by: Sagi Grimberg <s...@grimberg.me>
Signed-off-by: Jason Gunthorpe <j...@mellanox.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
---
 drivers/infiniband/ulp/isert/ib_isert.c | 7 +++++++
 drivers/infiniband/ulp/isert/ib_isert.h | 1 +
 2 files changed, 8 insertions(+)

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c 
b/drivers/infiniband/ulp/isert/ib_isert.c
index 0983470929bd..b879d21b7548 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -2098,6 +2098,9 @@ isert_rdma_rw_ctx_post(struct isert_cmd *cmd, struct 
isert_conn *conn,
        u32 rkey, offset;
        int ret;
 
+       if (cmd->ctx_init_done)
+               goto rdma_ctx_post;
+
        if (dir == DMA_FROM_DEVICE) {
                addr = cmd->write_va;
                rkey = cmd->write_stag;
@@ -2125,11 +2128,15 @@ isert_rdma_rw_ctx_post(struct isert_cmd *cmd, struct 
isert_conn *conn,
                                se_cmd->t_data_sg, se_cmd->t_data_nents,
                                offset, addr, rkey, dir);
        }
+
        if (ret < 0) {
                isert_err("Cmd: %p failed to prepare RDMA res\n", cmd);
                return ret;
        }
 
+       cmd->ctx_init_done = true;
+
+rdma_ctx_post:
        ret = rdma_rw_ctx_post(&cmd->rw, conn->qp, port_num, cqe, chain_wr);
        if (ret < 0)
                isert_err("Cmd: %p failed to post RDMA res\n", cmd);
diff --git a/drivers/infiniband/ulp/isert/ib_isert.h 
b/drivers/infiniband/ulp/isert/ib_isert.h
index c02ada57d7f5..85bd19753d55 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -124,6 +124,7 @@ struct isert_cmd {
        struct rdma_rw_ctx      rw;
        struct work_struct      comp_work;
        struct scatterlist      sg;
+       bool                    ctx_init_done;
 };
 
 static inline struct isert_cmd *tx_desc_to_cmd(struct iser_tx_desc *desc)
-- 
2.14.1