userfaultfd: revert "userfaultfd: waitqueue: add nr wake parameter to __wake_up_locke...

This reverts commit 51360155eccb907ff8635bd10fc7de876408c2e0 and adapts
fs/userfaultfd.c to use the old version of that function.

It didn't look robust to call __wake_up_common with "nr == 1" when we
absolutely require wakeall semantics, but we've full control of what we
insert in the two waitqueue heads of the blocked userfaults.  No
exclusive waitqueue risks to be inserted into those two waitqueue heads
so we can as well stick to "nr == 1" of the old code and we can rely
purely on the fact no waitqueue inserted in one of the two waitqueue
heads we must enforce as wakeall, has wait->flags WQ_FLAG_EXCLUSIVE set.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index f9aeb40a7197475ec52ba414852ff356129b0aab..50311703135bc8c699bcc3d26d0b9aa24b5277f3 100644 (file)
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -467,8 +467,8 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
         * the fault_*wqh.
         */
        spin_lock(&ctx->fault_pending_wqh.lock);
-       __wake_up_locked_key(&ctx->fault_pending_wqh, TASK_NORMAL, 0, &range);
-       __wake_up_locked_key(&ctx->fault_wqh, TASK_NORMAL, 0, &range);
+       __wake_up_locked_key(&ctx->fault_pending_wqh, TASK_NORMAL, &range);
+       __wake_up_locked_key(&ctx->fault_wqh, TASK_NORMAL, &range);
        spin_unlock(&ctx->fault_pending_wqh.lock);
 
        wake_up_poll(&ctx->fd_wqh, POLLHUP);
@@ -650,10 +650,10 @@ static void __wake_userfault(struct userfaultfd_ctx *ctx,
        spin_lock(&ctx->fault_pending_wqh.lock);
        /* wake all in the range and autoremove */
        if (waitqueue_active(&ctx->fault_pending_wqh))
-               __wake_up_locked_key(&ctx->fault_pending_wqh, TASK_NORMAL, 0,
+               __wake_up_locked_key(&ctx->fault_pending_wqh, TASK_NORMAL,
                                     range);
        if (waitqueue_active(&ctx->fault_wqh))
-               __wake_up_locked_key(&ctx->fault_wqh, TASK_NORMAL, 0, range);
+               __wake_up_locked_key(&ctx->fault_wqh, TASK_NORMAL, range);
        spin_unlock(&ctx->fault_pending_wqh.lock);
 }
 

diff --git a/include/linux/wait.h b/include/linux/wait.h
index d3d077228d4c155ad4b08a6668dc725679996372..1e1bf9f963a947fc686125d0a2809ad63b8a13ed 100644 (file)
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -147,8 +147,7 @@ __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
 
 typedef int wait_bit_action_f(struct wait_bit_key *);
 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
-void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, int nr,
-                         void *key);
+void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
@@ -180,7 +179,7 @@ wait_queue_head_t *bit_waitqueue(void *, int);
 #define wake_up_poll(x, m)                                             \
        __wake_up(x, TASK_NORMAL, 1, (void *) (m))
 #define wake_up_locked_poll(x, m)                                      \
-       __wake_up_locked_key((x), TASK_NORMAL, 1, (void *) (m))
+       __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
 #define wake_up_interruptible_poll(x, m)                               \
        __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
 #define wake_up_interruptible_sync_poll(x, m)                          \

diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index 272d9322bc5dfb6b82e650950e16ab89b572f442..052e02672d12428ce1e9e1f7266c7cd754ace5af 100644 (file)
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -106,10 +106,9 @@ void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr)
 }
 EXPORT_SYMBOL_GPL(__wake_up_locked);
 
-void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, int nr,
-                         void *key)
+void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
 {
-       __wake_up_common(q, mode, nr, 0, key);
+       __wake_up_common(q, mode, 1, 0, key);
 }
 EXPORT_SYMBOL_GPL(__wake_up_locked_key);
 
@@ -284,7 +283,7 @@ void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
        if (!list_empty(&wait->task_list))
                list_del_init(&wait->task_list);
        else if (waitqueue_active(q))
-               __wake_up_locked_key(q, mode, 1, key);
+               __wake_up_locked_key(q, mode, key);
        spin_unlock_irqrestore(&q->lock, flags);
 }
 EXPORT_SYMBOL(abort_exclusive_wait);

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index b140c092d226edd7d207f077e511d828cc08a615..337ca851a350cc412532ff4d3c96d87a8605e785 100644 (file)
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -297,7 +297,7 @@ static int rpc_complete_task(struct rpc_task *task)
        clear_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
        ret = atomic_dec_and_test(&task->tk_count);
        if (waitqueue_active(wq))
-               __wake_up_locked_key(wq, TASK_NORMAL, 1, &k);
+               __wake_up_locked_key(wq, TASK_NORMAL, &k);
        spin_unlock_irqrestore(&wq->lock, flags);
        return ret;
 }