staging: lustre: add container_of_safe()

Luster has a container_of0() function which is similar to
container_of() but passes an IS_ERR_OR_NULL() pointer through
unchanged.
This could be generally useful: bcache at last has a similar function.

Naming is hard, but the precedent set by hlist_entry_safe() suggests
a _safe suffix might be most consistent.

So add container_of_safe() to kernel.h, and replace all occurrences of
container_of0() with one of
  - list_first_entry, list_next_entry, when that is a better fit,
  - container_of(), when the pointer is used as a validpointer in
    surrounding code,
  - container_of_safe() when there is no obviously better alternative.

Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 0 insertions, 11 deletions

diff --git a/drivers/staging/lustre/include/linux/libcfs/libcfs.h b/drivers/staging/lustre/include/linux/libcfs/libcfs.h
index 5d10aa3..6e7754b 100644
--- a/drivers/staging/lustre/include/linux/libcfs/libcfs.h
+++ b/drivers/staging/lustre/include/linux/libcfs/libcfs.h
@@ -143,17 +143,6 @@ int libcfs_ioctl_getdata(struct libcfs_ioctl_hdr **hdr_pp,
 int libcfs_ioctl_data_adjust(struct libcfs_ioctl_data *data);
 int libcfs_ioctl(unsigned long cmd, void __user *arg);
 
-/* container_of depends on "likely" which is defined in libcfs_private.h */
-static inline void *__container_of(void *ptr, unsigned long shift)
-{
-	if (IS_ERR_OR_NULL(ptr))
-		return ptr;
-	return (char *)ptr - shift;
-}
-
-#define container_of0(ptr, type, member) \
-	((type *)__container_of((void *)(ptr), offsetof(type, member)))
-
 #define _LIBCFS_H
 
 extern struct miscdevice libcfs_dev;