[PATCH] userfaultfdv4.2 update for -mm

[PATCH] userfaultfdv4.2 update for -mm

[Andrea Arcangeli]

Oops there was a leftover _irq, now I also checked there's no other
irq leftover, the word "irq" disappeared from the file.

The patch applies at the end but ideally should be moved earlier
(anywhere before the patch that activates the syscall).

Thanks,
Andrea

Andrea Arcangeli (1):
  userfaultfd: cleanup superfluous _irq locking

 fs/userfaultfd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

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[PATCH] userfaultfd: cleanup superfluous _irq locking

[Andrea Arcangeli]

This leftover shouldn't have caused any malfunction because the loop
either schedules or it re-enables irqs immediately and schedule()
doesn't seem to BUG_ON(irqs_disabled()). However lately we've been
using the non blocking model so the schedule isn't really exercised
here. Regardless of the side effects this must be fixed as it's not ok
to enter schedule with irq disabled and it's not beneficial to toggle
irqs in the first place.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
---
 fs/userfaultfd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index a519f74..5f11678 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -558,11 +558,11 @@ static ssize_t userfaultfd_ctx_read(struct userfaultfd_ctx *ctx, int no_wait,
 		}
 		spin_unlock(&ctx->fd_wqh.lock);
 		schedule();
-		spin_lock_irq(&ctx->fd_wqh.lock);
+		spin_lock(&ctx->fd_wqh.lock);
 	}
 	__remove_wait_queue(&ctx->fd_wqh, &wait);
 	__set_current_state(TASK_RUNNING);
-	spin_unlock_irq(&ctx->fd_wqh.lock);
+	spin_unlock(&ctx->fd_wqh.lock);
 
 	return ret;
 }

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