5.15-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit c0219c499799c1e92bd570c15a47e6257a27bb15 ]
Neil says: "These functions were separated in commit 0971374e2818 ("SUNRPC: Reduce contention in svc_xprt_enqueue()") so that the XPT_BUSY check happened before taking any spinlocks.
We have since moved or removed the spinlocks so the extra test is fairly pointless."
I've made this a separate patch in case the XPT_BUSY change has unexpected consequences and needs to be reverted.
Suggested-by: Neil Brown neilb@suse.de Signed-off-by: Chuck Lever chuck.lever@oracle.com --- net/sunrpc/svc_xprt.c | 26 ++++++++++---------------- 1 file changed, 10 insertions(+), 16 deletions(-)
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 795dc8eb2e1d5..5a6d4ccb4a607 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -31,7 +31,6 @@ static int svc_deferred_recv(struct svc_rqst *rqstp); static struct cache_deferred_req *svc_defer(struct cache_req *req); static void svc_age_temp_xprts(struct timer_list *t); static void svc_delete_xprt(struct svc_xprt *xprt); -static void svc_xprt_do_enqueue(struct svc_xprt *xprt);
/* apparently the "standard" is that clients close * idle connections after 5 minutes, servers after @@ -268,12 +267,12 @@ void svc_xprt_received(struct svc_xprt *xprt) trace_svc_xprt_received(xprt);
/* As soon as we clear busy, the xprt could be closed and - * 'put', so we need a reference to call svc_xprt_do_enqueue with: + * 'put', so we need a reference to call svc_xprt_enqueue with: */ svc_xprt_get(xprt); smp_mb__before_atomic(); clear_bit(XPT_BUSY, &xprt->xpt_flags); - svc_xprt_do_enqueue(xprt); + svc_xprt_enqueue(xprt); svc_xprt_put(xprt); } EXPORT_SYMBOL_GPL(svc_xprt_received); @@ -413,6 +412,8 @@ static bool svc_xprt_ready(struct svc_xprt *xprt) smp_rmb(); xpt_flags = READ_ONCE(xprt->xpt_flags);
+ if (xpt_flags & BIT(XPT_BUSY)) + return false; if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE))) return true; if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) { @@ -425,7 +426,12 @@ static bool svc_xprt_ready(struct svc_xprt *xprt) return false; }
-static void svc_xprt_do_enqueue(struct svc_xprt *xprt) +/** + * svc_xprt_enqueue - Queue a transport on an idle nfsd thread + * @xprt: transport with data pending + * + */ +void svc_xprt_enqueue(struct svc_xprt *xprt) { struct svc_pool *pool; struct svc_rqst *rqstp = NULL; @@ -469,18 +475,6 @@ static void svc_xprt_do_enqueue(struct svc_xprt *xprt) put_cpu(); trace_svc_xprt_do_enqueue(xprt, rqstp); } - -/* - * Queue up a transport with data pending. If there are idle nfsd - * processes, wake 'em up. - * - */ -void svc_xprt_enqueue(struct svc_xprt *xprt) -{ - if (test_bit(XPT_BUSY, &xprt->xpt_flags)) - return; - svc_xprt_do_enqueue(xprt); -} EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
/*