svcrdma: Introduce svc_rdma_send_ctxt
authorChuck Lever <chuck.lever@oracle.com>
Mon, 7 May 2018 19:28:04 +0000 (15:28 -0400)
committerJ. Bruce Fields <bfields@redhat.com>
Fri, 11 May 2018 19:48:57 +0000 (15:48 -0400)
commit4201c7464753827803366b40e82eb050c04ebdef
treee22275b92394c10cf40bed41ceb8900d530d3e3f
parent232627905f12a05df75853c62451ce0886803cee
svcrdma: Introduce svc_rdma_send_ctxt

svc_rdma_op_ctxt's are pre-allocated and maintained on a per-xprt
free list. This eliminates the overhead of calling kmalloc / kfree,
both of which grab a globally shared lock that disables interrupts.
Introduce a replacement to svc_rdma_op_ctxt's that is built
especially for the svcrdma Send path.

Subsequent patches will take advantage of this new structure by
allocating real resources which are then cached in these objects.
The allocations are freed when the transport is torn down.

I've renamed the structure so that static type checking can be used
to ensure that uses of op_ctxt and send_ctxt are not confused. As an
additional clean up, structure fields are renamed to conform with
kernel coding conventions.

Additional clean ups:
- Handle svc_rdma_send_ctxt_get allocation failure at each call
  site, rather than pre-allocating and hoping we guessed correctly
- All send_ctxt_put call-sites request page freeing, so remove
  the @free_pages argument
- All send_ctxt_put call-sites unmap SGEs, so fold that into
  svc_rdma_send_ctxt_put

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
include/linux/sunrpc/svc_rdma.h
net/sunrpc/xprtrdma/svc_rdma_backchannel.c
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
net/sunrpc/xprtrdma/svc_rdma_sendto.c
net/sunrpc/xprtrdma/svc_rdma_transport.c