RDS/IB: get the xmit max_sge from the RDS IB device on the connection
rds_ib_xmit_rdma() was calling ib_get_client_data() to get at the rds_ibdevice
just to get the max_sge for the transmit. This patch instead has it get it
directly off the rds_ibdev which is stored on the connection.
The current code won't free the rds_ibdev until all the IB connections that use
it are freed. So it's safe to reference the rds_ibdev this way. In the future
it also makes it easier to support proper reference counting of the rds_ibdev
struct.
As an additional bonus, this gets rid of the performance hit of calling in to
the IB stack to look up the rds_ibdev. The current implementation in the IB
stack acquires an interrupt blocking spinlock to protect the registration of
client callback data.
Signed-off-by: Zach Brown <zach.brown@oracle.com>
diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c
index 209dbc6..3f91e79 100644
--- a/net/rds/ib_send.c
+++ b/net/rds/ib_send.c
@@ -806,10 +806,10 @@
struct rds_ib_send_work *first;
struct rds_ib_send_work *prev;
struct ib_send_wr *failed_wr;
- struct rds_ib_device *rds_ibdev;
struct scatterlist *scat;
unsigned long len;
u64 remote_addr = op->op_remote_addr;
+ u32 max_sge = ic->rds_ibdev->max_sge;
u32 pos;
u32 work_alloc;
u32 i;
@@ -818,8 +818,6 @@
int ret;
int num_sge;
- rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client);
-
/* map the op the first time we see it */
if (!op->op_mapped) {
op->op_count = ib_dma_map_sg(ic->i_cm_id->device,
@@ -839,7 +837,7 @@
* Instead of knowing how to return a partial rdma read/write we insist that there
* be enough work requests to send the entire message.
*/
- i = ceil(op->op_count, rds_ibdev->max_sge);
+ i = ceil(op->op_count, max_sge);
work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
if (work_alloc != i) {
@@ -867,9 +865,9 @@
send->s_wr.wr.rdma.remote_addr = remote_addr;
send->s_wr.wr.rdma.rkey = op->op_rkey;
- if (num_sge > rds_ibdev->max_sge) {
- send->s_wr.num_sge = rds_ibdev->max_sge;
- num_sge -= rds_ibdev->max_sge;
+ if (num_sge > max_sge) {
+ send->s_wr.num_sge = max_sge;
+ num_sge -= max_sge;
} else {
send->s_wr.num_sge = num_sge;
}
