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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2022-05-10 17:38:33 +0300
committerChuck Lever <chuck.lever@oracle.com>2022-05-19 19:25:40 +0300
commit586095d339b1b46f4283863e6e8e15de662a3f93 (patch)
tree75c581d0e3e6e0141eddebd654f1ca3501c62195 /net/sunrpc
parente9488d5ae13c0a72223c507e2508dc2ac66cad4f (diff)
downloadlinux-586095d339b1b46f4283863e6e8e15de662a3f93.tar.xz
SUNRPC: Don't disable preemption while calling svc_pool_for_cpu().
svc_xprt_enqueue() disables preemption via get_cpu() and then asks for a pool of a specific CPU (current) via svc_pool_for_cpu(). While preemption is disabled, svc_xprt_enqueue() acquires svc_pool::sp_lock with bottom-halfs disabled, which can sleep on PREEMPT_RT. Disabling preemption is not required here. The pool is protected with a lock so the following list access is safe even cross-CPU. The following iteration through svc_pool::sp_all_threads is under RCU-readlock and remaining operations within the loop are atomic and do not rely on disabled-preemption. Use raw_smp_processor_id() as the argument for the requested CPU in svc_pool_for_cpu(). Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/svc_xprt.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index f9d9922f1629..66cf720853bb 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -448,7 +448,6 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
{
struct svc_pool *pool;
struct svc_rqst *rqstp = NULL;
- int cpu;
if (!svc_xprt_ready(xprt))
return;
@@ -461,8 +460,7 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
return;
- cpu = get_cpu();
- pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
+ pool = svc_pool_for_cpu(xprt->xpt_server, raw_smp_processor_id());
atomic_long_inc(&pool->sp_stats.packets);
@@ -485,7 +483,6 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
rqstp = NULL;
out_unlock:
rcu_read_unlock();
- put_cpu();
trace_svc_xprt_enqueue(xprt, rqstp);
}
EXPORT_SYMBOL_GPL(svc_xprt_enqueue);