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authorZhang Xiaoxu <zhangxiaoxu5@huawei.com>2021-06-26 10:50:42 +0300
committerTrond Myklebust <trond.myklebust@hammerspace.com>2021-06-28 16:34:39 +0300
commit5483b904bf336948826594610af4c9bbb0d9e3aa (patch)
tree1567c5ce95219602d4e4c5d34d78a7afd788a0b1 /net/sunrpc/sched.c
parentfcb170a9d825d7db4a3fb870b0300f5a40a8d096 (diff)
downloadlinux-5483b904bf336948826594610af4c9bbb0d9e3aa.tar.xz
SUNRPC: Should wake up the privileged task firstly.
When find a task from wait queue to wake up, a non-privileged task may be found out, rather than the privileged. This maybe lead a deadlock same as commit dfe1fe75e00e ("NFSv4: Fix deadlock between nfs4_evict_inode() and nfs4_opendata_get_inode()"): Privileged delegreturn task is queued to privileged list because all the slots are assigned. If there has no enough slot to wake up the non-privileged batch tasks(session less than 8 slot), then the privileged delegreturn task maybe lost waked up because the found out task can't get slot since the session is on draining. So we should treate the privileged task as the emergency task, and execute it as for as we can. Reported-by: Hulk Robot <hulkci@huawei.com> Fixes: 5fcdfacc01f3 ("NFSv4: Return delegations synchronously in evict_inode") Cc: stable@vger.kernel.org Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'net/sunrpc/sched.c')
-rw-r--r--net/sunrpc/sched.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 71993adb0762..c045f63d11fa 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -592,6 +592,15 @@ static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *q
struct rpc_task *task;
/*
+ * Service the privileged queue.
+ */
+ q = &queue->tasks[RPC_NR_PRIORITY - 1];
+ if (queue->maxpriority > RPC_PRIORITY_PRIVILEGED && !list_empty(q)) {
+ task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
+ goto out;
+ }
+
+ /*
* Service a batch of tasks from a single owner.
*/
q = &queue->tasks[queue->priority];