[PATCH 3/3] 2.6.14-rc2-mm1 : fixes for overflow in sys_poll()

[Willy Tarreau]

This patch simplifies the overflow fix which was applied to sys_poll() in
2.6.14-rc2-mm1 by relying on the overflow detection code added to jiffies.h
by patch 1/3. This also removes a useless divide for HZ <= 1000.

It might be worth applying too. It's only for -mm1, and does *not* apply
to 2.6.14-rc2 because this code has already received patches in -mm1.

Signed-off-by: Willy Tarreau <willy@xxxxxxxxx>

- Willy


diff -purN linux-2.6.14-rc2-mm1/fs/select.c linux-2.6.14-rc2-mm1-poll/fs/select.c
--- linux-2.6.14-rc2-mm1/fs/select.c	Sat Sep 24 21:12:36 2005
+++ linux-2.6.14-rc2-mm1-poll/fs/select.c	Sat Sep 24 21:23:21 2005
@@ -469,7 +469,6 @@ asmlinkage long sys_poll(struct pollfd _
 {
 	struct poll_wqueues table;
 	int fdcount, err;
-	int overflow;
  	unsigned int i;
 	struct poll_list *head;
  	struct poll_list *walk;
@@ -486,22 +485,11 @@ asmlinkage long sys_poll(struct pollfd _
 		return -EINVAL;
 
 	/*
-	 * We compare HZ with 1000 to work out which side of the
-	 * expression needs conversion.  Because we want to avoid
-	 * converting any value to a numerically higher value, which
-	 * could overflow.
-	 */
-#if HZ > 1000
-	overflow = timeout_msecs >= jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT);
-#else
-	overflow = msecs_to_jiffies(timeout_msecs) >= MAX_SCHEDULE_TIMEOUT;
-#endif
-
-	/*
 	 * If we would overflow in the conversion or a negative timeout
-	 * is requested, sleep indefinitely.
+	 * is requested, sleep indefinitely. Note: msecs_to_jiffies checks
+	 * for the overflow.
 	 */
-	if (overflow || timeout_msecs < 0)
+	if (timeout_msecs < 0)
 		timeout_jiffies = MAX_SCHEDULE_TIMEOUT;
 	else
 		timeout_jiffies = msecs_to_jiffies(timeout_msecs) + 1;


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