From: Vu Pham <vu@xxxxxxxxxxxx>
For small IOs, stop using frwr. DMA mr is sufficient
Signed-off-by: Vu Pham <vu@xxxxxxxxxxxx>
---
drivers/infiniband/ulp/isert/ib_isert.c | 32 +++++++++++++++++++-----------
1 files changed, 20 insertions(+), 12 deletions(-)
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 3591855..6ce4db2 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -2259,18 +2259,26 @@ isert_reg_rdma_frwr(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
data_len = min(data_left, rdma_write_max);
wr->cur_rdma_length = data_len;
- spin_lock_irqsave(&isert_conn->conn_lock, flags);
- fr_desc = list_first_entry(&isert_conn->conn_frwr_pool,
- struct fast_reg_descriptor, list);
- list_del(&fr_desc->list);
- spin_unlock_irqrestore(&isert_conn->conn_lock, flags);
- wr->fr_desc = fr_desc;
-
- ret = isert_fast_reg_mr(fr_desc, isert_cmd, isert_conn,
- ib_sge, offset, data_len);
- if (ret) {
- list_add_tail(&fr_desc->list, &isert_conn->conn_frwr_pool);
- goto unmap_sg;
+ /* if there is a single dma entry, dma mr is sufficient */
+ if (count == 1) {
+ ib_sge->addr = ib_sg_dma_address(ib_dev, &sg_start[0]);
+ ib_sge->length = ib_sg_dma_len(ib_dev, &sg_start[0]);
+ ib_sge->lkey = isert_conn->conn_mr->lkey;
+ wr->fr_desc = NULL;
+ } else {
+ spin_lock_irqsave(&isert_conn->conn_lock, flags);
+ fr_desc = list_first_entry(&isert_conn->conn_frwr_pool,
+ struct fast_reg_descriptor, list);
+ list_del(&fr_desc->list);
+ spin_unlock_irqrestore(&isert_conn->conn_lock, flags);
+ wr->fr_desc = fr_desc;
+
+ ret = isert_fast_reg_mr(fr_desc, isert_cmd, isert_conn,
+ ib_sge, offset, data_len);
+ if (ret) {
+ list_add_tail(&fr_desc->list, &isert_conn->conn_frwr_pool);
+ goto unmap_sg;
+ }
}
return 0;
--
1.7.1
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