The patch titled
epoll: drop unnecessary test
has been added to the -mm tree. Its filename is
epoll-drop-unnecessary-test.patch
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------------------------------------------------------
Subject: epoll: drop unnecessary test
From: Davide Libenzi <davidel@xxxxxxxxxxxxxxx>
Thomas found that there is an unnecessary (always true) test in
ep_send_events(). The callback never inserts into ->rdllink while the
send loop is performed, and also does the ~EP_PRIVATE_BITS test. Given
we're holding the mutex during this time, the conditions tested inside the
loop are always true. This patch drops the test done inside the
re-insertion loop.
Signed-off-by: Davide Libenzi <davidel@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/eventpoll.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff -puN fs/eventpoll.c~epoll-drop-unnecessary-test fs/eventpoll.c
--- a/fs/eventpoll.c~epoll-drop-unnecessary-test
+++ a/fs/eventpoll.c
@@ -927,14 +927,11 @@ errxit:
/*
* During the time we spent in the loop above, some other events
* might have been queued by the poll callback. We re-insert them
- * here (in case they are not already queued, or they're one-shot).
+ * inside the main ready-list here.
*/
for (nepi = ep->ovflist; (epi = nepi) != NULL;
- nepi = epi->next, epi->next = EP_UNACTIVE_PTR) {
- if (!ep_is_linked(&epi->rdllink) &&
- (epi->event.events & ~EP_PRIVATE_BITS))
- list_add_tail(&epi->rdllink, &ep->rdllist);
- }
+ nepi = epi->next, epi->next = EP_UNACTIVE_PTR)
+ list_add_tail(&epi->rdllink, &ep->rdllist);
/*
* We need to set back ep->ovflist to EP_UNACTIVE_PTR, so that after
* releasing the lock, events will be queued in the normal way inside
_
Patches currently in -mm which might be from davidel@xxxxxxxxxxxxxxx are
epoll-drop-unnecessary-test.patch
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