[PATCH] sched: Fix sched_getaffinity

[Anton Blanchard <anton@samba.org>]

taskset on 2.6.34-rc3 fails on one of my ppc64 test boxes with the following
error:

sched_getaffinity(0, 16, 0x10029650030) = -1 EINVAL (Invalid argument)

This box has 128 threads and 16 bytes is enough to cover it. Commit
cd3d8031eb4311e516329aee03c79a08333141f1 (sched: sched_getaffinity(): Allow
less than NR_CPUS length) is comparing this 16 bytes agains nr_cpu_ids.

Fix it by comparing nr_cpu_ids to the number of bits in the cpumask we pass in.

Signed-off-by: Anton Blanchard <anton@samba.org>
---

diff --git a/kernel/sched.c b/kernel/sched.c
index 49d2fa7..0c1ec87 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4902,7 +4902,7 @@ SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
 	int ret;
 	cpumask_var_t mask;
 
-	if (len < nr_cpu_ids)
+	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
 		return -EINVAL;
 	if (len & (sizeof(unsigned long)-1))
 		return -EINVAL;