From: Chuck Lever <chuck.lever@oracle.com>
Date: Mon, 5 Mar 2018 15:13:13 -0500
Subject: SUNRPC: Make num_reqs a non-atomic integer
Patch-mainline: v4.17-rc1
Git-commit: ff699ea8269a02d977c6ee42d58f76efe83a34f9
References: bsc#1123036
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
include/linux/sunrpc/xprt.h | 2 +-
net/sunrpc/xprt.c | 17 +++++++++--------
2 files changed, 10 insertions(+), 9 deletions(-)
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -196,7 +196,7 @@ 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
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1002,7 +1002,7 @@ 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);
@@ -1041,9 +1041,6 @@ 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;
@@ -1105,14 +1102,15 @@ static struct rpc_rqst *xprt_dynamic_all
{
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;
@@ -1120,7 +1118,8 @@ out:
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;
}
@@ -1155,6 +1154,8 @@ void xprt_alloc_slot(struct rpc_xprt *xp
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);
@@ -1222,7 +1223,7 @@ struct rpc_xprt *xprt_alloc(struct net *
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;