Add suspend-related notifications for CPU hotplug

Since nonboot CPUs are now disabled after tasks and devices have been
frozen and the CPU hotplug infrastructure is used for this purpose, we need
special CPU hotplug notifications that will help the CPU-hotplug-aware
subsystems distinguish normal CPU hotplug events from CPU hotplug events
related to a system-wide suspend or resume operation in progress.  This
patch introduces such notifications and causes them to be used during
suspend and resume transitions.  It also changes all of the
CPU-hotplug-aware subsystems to take these notifications into consideration
(for now they are handled in the same way as the corresponding "normal"
ones).

[oleg@tv-sign.ru: cleanups]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 4 insertions, 1 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index fc2d763a8d78..aecd057cd0e0 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2946,7 +2946,7 @@ static void buffer_exit_cpu(int cpu)
 static int buffer_cpu_notify(struct notifier_block *self,
                               unsigned long action, void *hcpu)
 {
-        if (action == CPU_DEAD)
+        if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
                 buffer_exit_cpu((unsigned long)hcpu);
         return NOTIFY_OK;
 }
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index f5aa3ef855fb..a96bde6df96d 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1734,11 +1734,13 @@ xfs_icsb_cpu_notify(
                         per_cpu_ptr(mp->m_sb_cnts, (unsigned long)hcpu);
         switch (action) {
         case CPU_UP_PREPARE:
+        case CPU_UP_PREPARE_FROZEN:
                 /* Easy Case - initialize the area and locks, and
                  * then rebalance when online does everything else for us. */
                 memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
                 break;
         case CPU_ONLINE:
+        case CPU_ONLINE_FROZEN:
                 xfs_icsb_lock(mp);
                 xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0, 0);
                 xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0, 0);
@@ -1746,6 +1748,7 @@ xfs_icsb_cpu_notify(
                 xfs_icsb_unlock(mp);
                 break;
         case CPU_DEAD:
+        case CPU_DEAD_FROZEN:
                 /* Disable all the counters, then fold the dead cpu's
                  * count into the total on the global superblock and
                  * re-enable the counters. */