[PATCH] fs: sys_poll with timeout -1 bug fix

If you do a poll() call with timeout -1, the wait will be a big number
(depending on HZ) instead of infinite wait, since -1 is passed to the
msecs_to_jiffies function.

Signed-off-by: Frode Isaksen <frode.isaksen@gmail.com>
Acked-by: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/select.c b/fs/select.c
index 9c4f0f2604f1..33b72ba0f86f 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -746,9 +746,9 @@ out_fds:
 asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
                         long timeout_msecs)
 {
-        s64 timeout_jiffies = 0;
+        s64 timeout_jiffies;
 
-        if (timeout_msecs) {
+        if (timeout_msecs > 0) {
 #if HZ > 1000
                 /* We can only overflow if HZ > 1000 */
                 if (timeout_msecs / 1000 > (s64)0x7fffffffffffffffULL / (s64)HZ)
@@ -756,6 +756,9 @@ asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
                 else
 #endif
                         timeout_jiffies = msecs_to_jiffies(timeout_msecs);
+        } else {
+                /* Infinite (< 0) or no (0) timeout */
+                timeout_jiffies = timeout_msecs;
         }
 
         return do_sys_poll(ufds, nfds, &timeout_jiffies);