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xprtrdma: Simplify locking that protects the rl_allreqs list

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Clean up: There's little chance of contention between the use of
rb_lock and rb_reqslock, so merge the two. This avoids having to
take both in some (possibly future) cases.

Transport tear-down is already serialized, thus there is no need for
locking at all when destroying rpcrdma_reqs.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Chuck Lever 2018-12-19 10:59:33 -05:00 committed by Anna Schumaker
parent 236b0943d1
commit 92f4433e56
3 changed files with 23 additions and 35 deletions
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20
net/sunrpc/xprtrdma/backchannel.c
View File

@ -19,29 +19,16 @@
#undef RPCRDMA_BACKCHANNEL_DEBUG
static void rpcrdma_bc_free_rqst(struct rpcrdma_xprt *r_xprt,
struct rpc_rqst *rqst)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
spin_lock(&buf->rb_reqslock);
list_del(&req->rl_all);
spin_unlock(&buf->rb_reqslock);
rpcrdma_destroy_req(req);
}
static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt,
unsigned int count)
{
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
struct rpcrdma_req *req;
struct rpc_rqst *rqst;
unsigned int i;
for (i = 0; i < (count << 1); i++) {
struct rpcrdma_regbuf *rb;
struct rpcrdma_req *req;
size_t size;
req = rpcrdma_create_req(r_xprt);
@ -67,7 +54,7 @@ static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt,
return 0;
out_fail:
rpcrdma_bc_free_rqst(r_xprt, rqst);
rpcrdma_req_destroy(req);
return -ENOMEM;
}
@ -225,7 +212,6 @@ drop_connection:
*/
void xprt_rdma_bc_destroy(struct rpc_xprt *xprt, unsigned int reqs)
{
struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
struct rpc_rqst *rqst, *tmp;
spin_lock(&xprt->bc_pa_lock);
@ -233,7 +219,7 @@ void xprt_rdma_bc_destroy(struct rpc_xprt *xprt, unsigned int reqs)
list_del(&rqst->rq_bc_pa_list);
spin_unlock(&xprt->bc_pa_lock);
rpcrdma_bc_free_rqst(r_xprt, rqst);
rpcrdma_req_destroy(rpcr_to_rdmar(rqst));
spin_lock(&xprt->bc_pa_lock);
}

31
net/sunrpc/xprtrdma/verbs.c
View File

@ -1043,9 +1043,9 @@ rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
req->rl_buffer = buffer;
INIT_LIST_HEAD(&req->rl_registered);
spin_lock(&buffer->rb_reqslock);
spin_lock(&buffer->rb_lock);
list_add(&req->rl_all, &buffer->rb_allreqs);
spin_unlock(&buffer->rb_reqslock);
spin_unlock(&buffer->rb_lock);
return req;
}
@ -1113,7 +1113,6 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
INIT_LIST_HEAD(&buf->rb_send_bufs);
INIT_LIST_HEAD(&buf->rb_allreqs);
spin_lock_init(&buf->rb_reqslock);
for (i = 0; i < buf->rb_max_requests; i++) {
struct rpcrdma_req *req;
@ -1154,9 +1153,18 @@ rpcrdma_destroy_rep(struct rpcrdma_rep *rep)
kfree(rep);
}
/**
* rpcrdma_req_destroy - Destroy an rpcrdma_req object
* @req: unused object to be destroyed
*
* This function assumes that the caller prevents concurrent device
* unload and transport tear-down.
*/
void
rpcrdma_destroy_req(struct rpcrdma_req *req)
rpcrdma_req_destroy(struct rpcrdma_req *req)
{
list_del(&req->rl_all);
rpcrdma_free_regbuf(req->rl_recvbuf);
rpcrdma_free_regbuf(req->rl_sendbuf);
rpcrdma_free_regbuf(req->rl_rdmabuf);
@ -1214,19 +1222,14 @@ rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
rpcrdma_destroy_rep(rep);
}
spin_lock(&buf->rb_reqslock);
while (!list_empty(&buf->rb_allreqs)) {
while (!list_empty(&buf->rb_send_bufs)) {
struct rpcrdma_req *req;
req = list_first_entry(&buf->rb_allreqs,
struct rpcrdma_req, rl_all);
list_del(&req->rl_all);
spin_unlock(&buf->rb_reqslock);
rpcrdma_destroy_req(req);
spin_lock(&buf->rb_reqslock);
req = list_first_entry(&buf->rb_send_bufs,
struct rpcrdma_req, rl_list);
list_del(&req->rl_list);
rpcrdma_req_destroy(req);
}
spin_unlock(&buf->rb_reqslock);
rpcrdma_mrs_destroy(buf);
}

7
net/sunrpc/xprtrdma/xprt_rdma.h
View File

@ -392,14 +392,13 @@ struct rpcrdma_buffer {
spinlock_t rb_lock; /* protect buf lists */
struct list_head rb_send_bufs;
struct list_head rb_recv_bufs;
struct list_head rb_allreqs;
unsigned long rb_flags;
u32 rb_max_requests;
u32 rb_credits; /* most recent credit grant */
u32 rb_bc_srv_max_requests;
spinlock_t rb_reqslock; /* protect rb_allreqs */
struct list_head rb_allreqs;
u32 rb_bc_max_requests;
struct workqueue_struct *rb_completion_wq;
@ -522,7 +521,7 @@ int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
* Buffer calls - xprtrdma/verbs.c
*/
struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
void rpcrdma_destroy_req(struct rpcrdma_req *);
void rpcrdma_req_destroy(struct rpcrdma_req *req);
int rpcrdma_buffer_create(struct rpcrdma_xprt *);
void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_buffer *buf);