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authorSagi Grimberg <sagi@grimberg.me>2017-03-22 17:07:30 +0200
committerNicholas Bellinger <nab@linux-iscsi.org>2017-03-30 20:35:50 -0700
commit7a56dc8888be23f44158a85b92da45d545cbf548 (patch)
tree53ff04e53d41f5225f68ec19dfe0ed26ae173be8
parent555a65f66c3c4d9dd46a565418b0b655d861a723 (diff)
downloadtalos-obmc-linux-7a56dc8888be23f44158a85b92da45d545cbf548.tar.gz
talos-obmc-linux-7a56dc8888be23f44158a85b92da45d545cbf548.zip
iser-target: avoid posting a recv buffer twice
We pre-allocate our send-queues and might overflow them in case we have multi work-request operations which tend to occur for large RDMA transfers over devices with limited allowed sg elements. When we get to a queue-full condition we might retry again later, so track our receive buffers so we don't repost them for a retry case. Reported-by: Potnuri Bharat Teja <bharat@chelsio.com> Tested-by: Potnuri Bharat Teja <bharat@chelsio.com> Reviewed-by: Potnuri Bharat Teja <bharat@chelsio.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
-rw-r--r--drivers/infiniband/ulp/isert/ib_isert.c12
-rw-r--r--drivers/infiniband/ulp/isert/ib_isert.h3
2 files changed, 14 insertions, 1 deletions
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 9b33c0c97468..fcbed35e95a8 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -817,6 +817,7 @@ isert_post_recvm(struct isert_conn *isert_conn, u32 count)
rx_wr->sg_list = &rx_desc->rx_sg;
rx_wr->num_sge = 1;
rx_wr->next = rx_wr + 1;
+ rx_desc->in_use = false;
}
rx_wr--;
rx_wr->next = NULL; /* mark end of work requests list */
@@ -835,6 +836,15 @@ isert_post_recv(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc)
struct ib_recv_wr *rx_wr_failed, rx_wr;
int ret;
+ if (!rx_desc->in_use) {
+ /*
+ * if the descriptor is not in-use we already reposted it
+ * for recv, so just silently return
+ */
+ return 0;
+ }
+
+ rx_desc->in_use = false;
rx_wr.wr_cqe = &rx_desc->rx_cqe;
rx_wr.sg_list = &rx_desc->rx_sg;
rx_wr.num_sge = 1;
@@ -1397,6 +1407,8 @@ isert_recv_done(struct ib_cq *cq, struct ib_wc *wc)
return;
}
+ rx_desc->in_use = true;
+
ib_dma_sync_single_for_cpu(ib_dev, rx_desc->dma_addr,
ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
index c02ada57d7f5..87d994de8c91 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -60,7 +60,7 @@
#define ISER_RX_PAD_SIZE (ISCSI_DEF_MAX_RECV_SEG_LEN + 4096 - \
(ISER_RX_PAYLOAD_SIZE + sizeof(u64) + sizeof(struct ib_sge) + \
- sizeof(struct ib_cqe)))
+ sizeof(struct ib_cqe) + sizeof(bool)))
#define ISCSI_ISER_SG_TABLESIZE 256
@@ -85,6 +85,7 @@ struct iser_rx_desc {
u64 dma_addr;
struct ib_sge rx_sg;
struct ib_cqe rx_cqe;
+ bool in_use;
char pad[ISER_RX_PAD_SIZE];
} __packed;
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