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Commit 89bf9d41 authored by Zach Brown's avatar Zach Brown Committed by Andy Grover
Browse files

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: default avatarZach Brown <zach.brown@oracle.com>
parent a46ca94e

net/rds/ib_send.c

+5 −7
Original line number Diff line number Diff line
@@ -806,10 +806,10 @@ int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op) 
	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 rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op) 
	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 @@ int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op) 
	 * 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 @@ int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op) 
		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;

		}