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authorLars Ellenberg <lars.ellenberg@linbit.com>2014-04-28 18:43:35 +0200
committerJens Axboe <axboe@fb.com>2014-04-30 21:46:56 +0200
commitec4a340789be16831ae96be5f7552238a7a6e903 (patch)
tree5571ed3e41b1afaaf2633dc135e62351ed162aa8 /drivers/block
parentdrbd: Allow attaching of a newly created device to any backing device (diff)
downloadlinux-ec4a340789be16831ae96be5f7552238a7a6e903.tar.xz
linux-ec4a340789be16831ae96be5f7552238a7a6e903.zip
drbd: use list_first_entry_or_null in first_peer_device/first_connection
If there are no peer_devices or connections, I'd rather have NULL than some "arbitrary" address pretending to point to a struct. Helps to avoid hard to debug symptoms, in case we ever try to use and dereference a drbd_connection or drbd_peer_device where we in fact don't have any connection at all. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/drbd/drbd_int.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 297ba406cc2b..a76ceb344d64 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -853,7 +853,7 @@ static inline struct drbd_device *minor_to_device(unsigned int minor)
static inline struct drbd_peer_device *first_peer_device(struct drbd_device *device)
{
- return list_first_entry(&device->peer_devices, struct drbd_peer_device, peer_devices);
+ return list_first_entry_or_null(&device->peer_devices, struct drbd_peer_device, peer_devices);
}
#define for_each_resource(resource, _resources) \
@@ -2222,7 +2222,7 @@ static inline void drbd_md_flush(struct drbd_device *device)
static inline struct drbd_connection *first_connection(struct drbd_resource *resource)
{
- return list_first_entry(&resource->connections,
+ return list_first_entry_or_null(&resource->connections,
struct drbd_connection, connections);
}