[PATCH AUTOSEL for 4.14 39/67] iser-target: avoid reinitializing rdma contexts for isert commands

Sasha Levin
2018-03-08T06:42:26Z

From: Bharat Potnuri <bharat@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 <bharat@chelsio.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <alexander.levin@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 9d4785ba24cb..e770c17cbca9 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -2124,6 +2124,9 @@ 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;
@@ -2151,11 +2154,15 @@ 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 d6fd248320ae..3b296bac4f60 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -126,6 +126,7 @@ 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