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RDS/IB: get the xmit max_sge from the RDS IB device on the connection

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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>
This commit is contained in:
Zach Brown 2010-05-18 15:44:50 -07:00 committed by Andy Grover
parent a46ca94e7f
commit 89bf9d4158
1 changed files with 5 additions and 7 deletions
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12
net/rds/ib_send.c
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@ -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;
}