Signed-off-by: Neil Brown <[EMAIL PROTECTED]>

### Diffstat output
 ./drivers/md/raid5.c |   15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff ./drivers/md/raid5.c~current~ ./drivers/md/raid5.c
--- ./drivers/md/raid5.c~current~       2006-03-17 18:18:35.000000000 +1100
+++ ./drivers/md/raid5.c        2006-03-17 18:18:44.000000000 +1100
@@ -1766,6 +1766,14 @@ static int make_request(request_queue_t 
                if (likely(conf->expand_progress == MaxSector))
                        disks = conf->raid_disks;
                else {
+                       /* spinlock is needed as expand_progress may be
+                        * 64bit on a 32bit platform, and so it might be
+                        * possible to see a half-updated value
+                        * Ofcourse expand_progress could change after
+                        * the lock is dropped, so once we get a reference
+                        * to the stripe that we think it is, we will have
+                        * to check again.
+                        */
                        spin_lock_irq(&conf->device_lock);
                        disks = conf->raid_disks;
                        if (logical_sector >= conf->expand_progress)
@@ -1789,7 +1797,12 @@ static int make_request(request_queue_t 
                if (sh) {
                        if (unlikely(conf->expand_progress != MaxSector)) {
                                /* expansion might have moved on while waiting 
for a
-                                * stripe, so we much do the range check again.
+                                * stripe, so we must do the range check again.
+                                * Expansion could still move past after this
+                                * test, but as we are holding a reference to
+                                * 'sh', we know that if that happens,
+                                *  STRIPE_EXPANDING will get set and the 
expansion
+                                * won't proceed until we finish with the 
stripe.
                                 */
                                int must_retry = 0;
                                spin_lock_irq(&conf->device_lock);
-
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