epoll: fix compiler warning and optimize the non-blocking path

epoll: fix compiler warning and optimize the non-blocking path

Add a comment to ep_poll(), rename labels a bit clearly, fix a warning of
unused variable from gcc and optimize the non-blocking path a little.

Hinted-by: Andrew Morton <[email protected]>
Signed-off-by: Davide Libenzi <[email protected]>
[email protected]:

: The non-blocking ep_poll path optimization introduced skipping over the
: return value setup.
:
: Initialize it properly, my userspace gets upset by epoll_wait() returning
: random things.
:
: In addition, remove the reinitialization at the fetch_events label, the
: return value is garuanteed to be zero when execution reaches there.

[[email protected]: fix initialization]
Signed-off-by: Johannes Weiner <[email protected]>
Cc: Shawn Bohrer <[email protected]>
Acked-by: Davide Libenzi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>