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SUNRPC: Make num_reqs a non-atomic integer

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If recording xprt->stat.max_slots is moved into xprt_alloc_slot,
then xprt->num_reqs is never manipulated outside
xprt->reserve_lock. There's no longer a need for xprt->num_reqs to
be atomic.

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 2018-03-05 15:13:13 -05:00 committed by Anna Schumaker
parent 78215759e2
commit ff699ea826
2 changed files with 10 additions and 9 deletions
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2
include/linux/sunrpc/xprt.h
View file

@ -197,7 +197,7 @@ struct rpc_xprt {
struct list_head free; /* free slots */
unsigned int max_reqs; /* max number of slots */
unsigned int min_reqs; /* min number of slots */
atomic_t num_reqs; /* total slots */
unsigned int num_reqs; /* total slots */
unsigned long state; /* transport state */
unsigned char resvport : 1; /* use a reserved port */
atomic_t swapper; /* we're swapping over this

17
net/sunrpc/xprt.c
View file

@ -1009,7 +1009,7 @@ void xprt_transmit(struct rpc_task *task)
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
unsigned int connect_cookie;
int status, numreqs;
int status;
dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
@ -1047,9 +1047,6 @@ void xprt_transmit(struct rpc_task *task)
xprt->ops->set_retrans_timeout(task);
numreqs = atomic_read(&xprt->num_reqs);
if (numreqs > xprt->stat.max_slots)
xprt->stat.max_slots = numreqs;
xprt->stat.sends++;
xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs;
xprt->stat.bklog_u += xprt->backlog.qlen;
@ -1111,14 +1108,15 @@ static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt)
{
struct rpc_rqst *req = ERR_PTR(-EAGAIN);
if (!atomic_add_unless(&xprt->num_reqs, 1, xprt->max_reqs))
if (xprt->num_reqs >= xprt->max_reqs)
goto out;
++xprt->num_reqs;
spin_unlock(&xprt->reserve_lock);
req = kzalloc(sizeof(struct rpc_rqst), GFP_NOFS);
spin_lock(&xprt->reserve_lock);
if (req != NULL)
goto out;
atomic_dec(&xprt->num_reqs);
--xprt->num_reqs;
req = ERR_PTR(-ENOMEM);
out:
return req;
@ -1126,7 +1124,8 @@ static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt)
static bool xprt_dynamic_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
{
if (atomic_add_unless(&xprt->num_reqs, -1, xprt->min_reqs)) {
if (xprt->num_reqs > xprt->min_reqs) {
--xprt->num_reqs;
kfree(req);
return true;
}
@ -1162,6 +1161,8 @@ void xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
spin_unlock(&xprt->reserve_lock);
return;
out_init_req:
xprt->stat.max_slots = max_t(unsigned int, xprt->stat.max_slots,
xprt->num_reqs);
task->tk_status = 0;
task->tk_rqstp = req;
xprt_request_init(task, xprt);
@ -1229,7 +1230,7 @@ struct rpc_xprt *xprt_alloc(struct net *net, size_t size,
else
xprt->max_reqs = num_prealloc;
xprt->min_reqs = num_prealloc;
atomic_set(&xprt->num_reqs, num_prealloc);
xprt->num_reqs = num_prealloc;
return xprt;