diff mbox

[v4,3/5] IB/srpt: Limit the number of SG elements per work request

Message ID 446e3039-ec25-89d8-2583-5e60dd2bfc88@sandisk.com (mailing list archive)
State Accepted
Headers show

Commit Message

Bart Van Assche July 21, 2016, 8:03 p.m. UTC 
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@gmail.com>
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Steve Wise <swise@opengridcomputing.com>
Cc: Parav Pandit <pandit.parav@gmail.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: <stable@vger.kernel.org> #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(-)

Comments

Christoph Hellwig Aug. 1, 2016, 10:57 a.m. UTC | #1 
On Thu, Jul 21, 2016 at 01:03:47PM -0700, Bart Van Assche wrote:
> Limit the number of SG elements per work request to what the HCA
> and the queue pair support.

Looks fine,

Reviewed-by: Christoph Hellwig <hch@lst.de>
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diff mbox

Patch

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,