s390/zcore: release dump save area on restart or power down

[ Upstream commit dabdfac0e85c8c1e811b10c08742f49285e78a17 ]

The zFCP/NVMe standalone dumper is supposed to release the dump save area
resource as soon as possible but might fail to do so, for instance, if it
crashes. To avoid this situation, register a reboot notifier and ensure
the dump save area resource is released on reboot or power down.

Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Stable-dep-of: 0b18c852cc6f ("tracing: Have saved_cmdlines arrays all in one allocation")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
index 5f659fa9224a356ce6e75ee5d8518ac1ffc4e6a7..1aee6b2ae66fbc4073a93aef1e7afb59d9a37bc1 100644 (file)
--- a/drivers/s390/char/zcore.c
+++ b/drivers/s390/char/zcore.c
@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/debugfs.h>
+#include <linux/reboot.h>
 
 #include <asm/asm-offsets.h>
 #include <asm/ipl.h>
@@ -247,6 +248,28 @@ static int __init zcore_reipl_init(void)
        return 0;
 }
 
+static int zcore_reboot_and_on_panic_handler(struct notifier_block *self,
+                                            unsigned long         event,
+                                            void                  *data)
+{
+       if (hsa_available)
+               release_hsa();
+
+       return NOTIFY_OK;
+}
+
+static struct notifier_block zcore_reboot_notifier = {
+       .notifier_call  = zcore_reboot_and_on_panic_handler,
+       /* we need to be notified before reipl and kdump */
+       .priority       = INT_MAX,
+};
+
+static struct notifier_block zcore_on_panic_notifier = {
+       .notifier_call  = zcore_reboot_and_on_panic_handler,
+       /* we need to be notified before reipl and kdump */
+       .priority       = INT_MAX,
+};
+
 static int __init zcore_init(void)
 {
        unsigned char arch;
@@ -307,6 +330,9 @@ static int __init zcore_init(void)
        zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
                                             NULL, &zcore_hsa_fops);
 
+       register_reboot_notifier(&zcore_reboot_notifier);
+       atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier);
+
        return 0;
 fail:
        diag308(DIAG308_REL_HSA, NULL);