Limit the number of SG elements per work request to what the HCA
and the queue pair support.
Fixes: 34693573fde0 ("IB/srpt: Reduce QP buffer size")
Reported-by: Parav Pandit <pandit.parav@xxxxxxxxx>
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
Cc: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
Cc: Parav Pandit <pandit.parav@xxxxxxxxx>
Cc: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Cc: Laurence Oberman <loberman@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> #v4.7+
---
drivers/infiniband/ulp/srpt/ib_srpt.c | 3 ++-
drivers/infiniband/ulp/srpt/ib_srpt.h | 6 +++++-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 4a41556..9a3b954 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -1601,6 +1601,7 @@ static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
struct ib_qp_init_attr *qp_init;
struct srpt_port *sport = ch->sport;
struct srpt_device *sdev = sport->sdev;
+ const struct ib_device_attr *attrs = &sdev->device->attrs;
u32 srp_sq_size = sport->port_attrib.srp_sq_size;
int ret;
@@ -1638,7 +1639,7 @@ retry:
*/
qp_init->cap.max_send_wr = srp_sq_size / 2;
qp_init->cap.max_rdma_ctxs = srp_sq_size / 2;
- qp_init->cap.max_send_sge = SRPT_DEF_SG_PER_WQE;
+ qp_init->cap.max_send_sge = min(attrs->max_sge, SRPT_MAX_SG_PER_WQE);
qp_init->port_num = ch->sport->port;
ch->qp = ib_create_qp(sdev->pd, qp_init);
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h
index 3890304..5818787 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.h
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.h
@@ -106,7 +106,11 @@ enum {
SRP_LOGIN_RSP_MULTICHAN_MAINTAINED = 0x2,
SRPT_DEF_SG_TABLESIZE = 128,
- SRPT_DEF_SG_PER_WQE = 16,
+ /*
+ * An experimentally determined value that avoids that QP creation
+ * fails due to "swiotlb buffer is full" on systems using the swiotlb.
+ */
+ SRPT_MAX_SG_PER_WQE = 16,
MIN_SRPT_SQ_SIZE = 16,
DEF_SRPT_SQ_SIZE = 4096,
--
2.9.2
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