If a HCA supports the SG_GAPS_REG feature then a single memory
region of type IB_MR_TYPE_SG_GAPS is sufficient. This patch
reduces the number of memory regions that is allocated per SRP
session.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Israel Rukshin <israelr@xxxxxxxxxxxx>
Cc: Max Gurtovoy <maxg@xxxxxxxxxxxx>
Cc: Laurence Oberman <loberman@xxxxxxxxxx>
---
drivers/infiniband/ulp/srp/ib_srp.c | 43 ++++++++++++++++++++++---------------
1 file changed, 26 insertions(+), 17 deletions(-)
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 87efb702b1c6..2f85255d2aca 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -3356,25 +3356,34 @@ static ssize_t srp_create_target(struct device *dev,
}
if (srp_dev->use_fast_reg || srp_dev->use_fmr) {
- /*
- * FR and FMR can only map one HCA page per entry. If the
- * start address is not aligned on a HCA page boundary two
- * entries will be used for the head and the tail although
- * these two entries combined contain at most one HCA page of
- * data. Hence the "+ 1" in the calculation below.
- *
- * The indirect data buffer descriptor is contiguous so the
- * memory for that buffer will only be registered if
- * register_always is true. Hence add one to mr_per_cmd if
- * register_always has been set.
- */
+ bool gaps_reg = (ibdev->attrs.device_cap_flags &
+ IB_DEVICE_SG_GAPS_REG);
+
max_sectors_per_mr = srp_dev->max_pages_per_mr <<
(ilog2(srp_dev->mr_page_size) - 9);
- mr_per_cmd = register_always +
- (target->scsi_host->max_sectors + 1 +
- max_sectors_per_mr - 1) / max_sectors_per_mr;
- pr_debug("max_sectors = %u; max_pages_per_mr = %u; mr_page_size = %u; max_sectors_per_mr = %u; mr_per_cmd = %u\n",
- target->scsi_host->max_sectors,
+ if (!gaps_reg) {
+ /*
+ * FR and FMR can only map one HCA page per entry. If
+ * the start address is not aligned on a HCA page
+ * boundary two entries will be used for the head and
+ * the tail although these two entries combined
+ * contain at most one HCA page of data. Hence the "+
+ * 1" in the calculation below.
+ *
+ * The indirect data buffer descriptor is contiguous
+ * so the memory for that buffer will only be
+ * registered if register_always is true. Hence add
+ * one to mr_per_cmd if register_always has been set.
+ */
+ mr_per_cmd = register_always +
+ (target->scsi_host->max_sectors + 1 +
+ max_sectors_per_mr - 1) / max_sectors_per_mr;
+ mr_per_cmd = max(2U, mr_per_cmd);
+ } else {
+ mr_per_cmd = 1;
+ }
+ pr_debug("IB_DEVICE_SG_GAPS_REG = %d; max_sectors = %u; max_pages_per_mr = %u; mr_page_size = %u; max_sectors_per_mr = %u; mr_per_cmd = %u\n",
+ gaps_reg, target->scsi_host->max_sectors,
srp_dev->max_pages_per_mr, srp_dev->mr_page_size,
max_sectors_per_mr, mr_per_cmd);
}
--
2.11.0
--
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
