From: pmeda@akamai.com
When poll returns error, we do not need to copy out the the revents. When
poll returns succeess, we can copy pollfds in units of pages, since there
is no harm in copying fds and events back.
(akpm: this is a user-visible change. Previously, a poll() which returned
-EINTR would have copied some stuff into userspace anyway. Now it won't copy
anything. Silly/broken applications may care)
Signed-off-by: Prasanna Meda <pmeda@akamai.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/fs/select.c | 18 +++++++++---------
1 files changed, 9 insertions(+), 9 deletions(-)
diff -puN fs/select.c~poll-mini-optimisations fs/select.c
--- 25/fs/select.c~poll-mini-optimisations Wed Jan 12 15:34:34 2005
+++ 25-akpm/fs/select.c Wed Jan 12 15:34:34 2005
@@ -502,24 +502,24 @@ asmlinkage long sys_poll(struct pollfd _
}
i -= pp->len;
}
- fdcount = do_poll(nfds, head, &table, timeout);
+
+ err = fdcount = do_poll(nfds, head, &table, timeout);
+ if (!fdcount && signal_pending(current))
+ err = -EINTR;
+ if (err < 0)
+ goto out_fds;
/* OK, now copy the revents fields back to user space. */
walk = head;
err = -EFAULT;
while(walk != NULL) {
struct pollfd *fds = walk->entries;
- int j;
-
- for (j=0; j < walk->len; j++, ufds++) {
- if(__put_user(fds[j].revents, &ufds->revents))
- goto out_fds;
- }
+ if (copy_to_user(ufds, fds, sizeof(struct pollfd) * walk->len))
+ goto out_fds;
+ ufds += walk->len;
walk = walk->next;
}
err = fdcount;
- if (!fdcount && signal_pending(current))
- err = -EINTR;
out_fds:
walk = head;
while(walk!=NULL) {
_