[PATCH] cpuset: might_sleep_if check in cpuset_zones_allowed

It's too easy to incorrectly call cpuset_zone_allowed() in an atomic
context without __GFP_HARDWALL set, and when done, it is not noticed until
a tight memory situation forces allocations to be tried outside the current
cpuset.

Add a 'might_sleep_if()' check, to catch this earlier on, instead of
waiting for a similar check in the mutex_lock() code, which is only rarely
invoked.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 57fd88237afc..ab81fdd4572b 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2261,6 +2261,7 @@ int __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
         if (in_interrupt())
                 return 1;
         node = z->zone_pgdat->node_id;
+        might_sleep_if(!(gfp_mask & __GFP_HARDWALL));
         if (node_isset(node, current->mems_allowed))
                 return 1;
         if (gfp_mask & __GFP_HARDWALL)  /* If hardwall request, stop here */