From: Mustafa Ismail <mustafa.ismail@xxxxxxxxx>
Running fio can occasionally cause a hang when sbitmap_queue_get() fails to
return a tag in iscsit_allocate_cmd() and iscsit_wait_for_tag() is called
and will never return from the schedule(). This is because the polling
thread of the CQ is suspended, and will not poll for a SQ completion which
would free up a tag.
Fix this by creating a separate CQ for the SQ so that send completions are
processed on a separate thread and are not blocked when the RQ CQ is
stalled.
Fixes: 10e9cbb6b531 ("scsi: target: Convert target drivers to use sbitmap")
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Signed-off-by: Mustafa Ismail <mustafa.ismail@xxxxxxxxx>
Signed-off-by: Shiraz Saleem <shiraz.saleem@xxxxxxxxx>
---
drivers/infiniband/ulp/isert/ib_isert.c | 33 +++++++++++++++++++++++----------
drivers/infiniband/ulp/isert/ib_isert.h | 3 ++-
2 files changed, 25 insertions(+), 11 deletions(-)
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 7540488..f827b91 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -109,19 +109,27 @@ static int isert_sg_tablesize_set(const char *val, const struct kernel_param *kp
struct ib_qp_init_attr attr;
int ret, factor;
- isert_conn->cq = ib_cq_pool_get(ib_dev, cq_size, -1, IB_POLL_WORKQUEUE);
- if (IS_ERR(isert_conn->cq)) {
- isert_err("Unable to allocate cq\n");
- ret = PTR_ERR(isert_conn->cq);
+ isert_conn->snd_cq = ib_cq_pool_get(ib_dev, cq_size, -1,
+ IB_POLL_WORKQUEUE);
+ if (IS_ERR(isert_conn->snd_cq)) {
+ isert_err("Unable to allocate send cq\n");
+ ret = PTR_ERR(isert_conn->snd_cq);
return ERR_PTR(ret);
}
+ isert_conn->rcv_cq = ib_cq_pool_get(ib_dev, cq_size, -1,
+ IB_POLL_WORKQUEUE);
+ if (IS_ERR(isert_conn->rcv_cq)) {
+ isert_err("Unable to allocate receive cq\n");
+ ret = PTR_ERR(isert_conn->rcv_cq);
+ goto create_cq_err;
+ }
isert_conn->cq_size = cq_size;
memset(&attr, 0, sizeof(struct ib_qp_init_attr));
attr.event_handler = isert_qp_event_callback;
attr.qp_context = isert_conn;
- attr.send_cq = isert_conn->cq;
- attr.recv_cq = isert_conn->cq;
+ attr.send_cq = isert_conn->snd_cq;
+ attr.recv_cq = isert_conn->rcv_cq;
attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS + 1;
attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS + 1;
factor = rdma_rw_mr_factor(device->ib_device, cma_id->port_num,
@@ -137,12 +145,16 @@ static int isert_sg_tablesize_set(const char *val, const struct kernel_param *kp
ret = rdma_create_qp(cma_id, device->pd, &attr);
if (ret) {
isert_err("rdma_create_qp failed for cma_id %d\n", ret);
- ib_cq_pool_put(isert_conn->cq, isert_conn->cq_size);
-
- return ERR_PTR(ret);
+ goto create_qp_err;
}
return cma_id->qp;
+create_qp_err:
+ ib_cq_pool_put(isert_conn->rcv_cq, isert_conn->cq_size);
+create_cq_err:
+ ib_cq_pool_put(isert_conn->snd_cq, isert_conn->cq_size);
+
+ return ERR_PTR(ret);
}
static int
@@ -409,7 +421,8 @@ static int isert_sg_tablesize_set(const char *val, const struct kernel_param *kp
isert_destroy_qp(struct isert_conn *isert_conn)
{
ib_destroy_qp(isert_conn->qp);
- ib_cq_pool_put(isert_conn->cq, isert_conn->cq_size);
+ ib_cq_pool_put(isert_conn->snd_cq, isert_conn->cq_size);
+ ib_cq_pool_put(isert_conn->rcv_cq, isert_conn->cq_size);
}
static int
diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
index 0b2dfd6..0cd43af 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -180,7 +180,8 @@ struct isert_conn {
struct iser_tx_desc login_tx_desc;
struct rdma_cm_id *cm_id;
struct ib_qp *qp;
- struct ib_cq *cq;
+ struct ib_cq *snd_cq;
+ struct ib_cq *rcv_cq;
u32 cq_size;
struct isert_device *device;
struct mutex mutex;
--
1.8.3.1
