For devices that can register page list that is bigger than
USHRT_MAX, we actually take the wrong value for sg_tablesize.
E.g: for CX4 max_fast_reg_page_list_len is 65536 (bigger than USHRT_MAX)
so we set sg_tablesize to 0 by mistake. Therefore, each IO that is
bigger than 4k splitted to "< 4k" chunks that cause performance degredation.
Fixes: 7854550ae6d8 ("RDMA/iser: Limit sgs to the device fastreg depth")
Signed-off-by: Max Gurtovoy <maxg@xxxxxxxxxxxx>
---
drivers/infiniband/ulp/iser/iscsi_iser.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index 9104e6b..ff37f19 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -656,7 +656,8 @@ static void iscsi_iser_cleanup_task(struct iscsi_task *task)
* max fastreg page list length.
*/
Hi Max,
shost->sg_tablesize = min_t(unsigned short, shost->sg_tablesize,
- ib_conn->device->ib_device->attrs.max_fast_reg_page_list_len);
+ min_t(unsigned int, USHRT_MAX,
+ ib_conn->device->ib_device->attrs.max_fast_reg_page_list_len));
Hmm, This looks broken since I fixed up mlx5 capability at:
911f4331bc87 ("IB/mlx5: Expose correct max_fast_reg_page_list_len")
However, I suspect this assignment should be removed altogether because
we already take that into account in the address resolution handler,
there the min statement is for unsigned and casted back to ushrt.
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
