IB/srpt: Limit the number of SG elements per work request

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+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Bart Van Assche 2016-07-21 13:03:47 -07:00 committed by Doug Ledford
parent 632bc3f650
commit 30c6d8773d
2 changed files with 7 additions and 2 deletions

View file

@ -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);

View file

@ -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,