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| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2020-10-15 20:11:31 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-22 11:47:57 +0200 |
| commit | 386a913d4960a83cc4657ebe0c9bc462d8f5e2a1 (patch) | |
| tree | 35e11b06a85a8a69a0a251e0044bb26eadab03ed /include | |
| parent | a52a5266080aa53dce51d58efdfd7b69b85d08fb (diff) | |
| download | linux-stable-386a913d4960a83cc4657ebe0c9bc462d8f5e2a1.tar.gz linux-stable-386a913d4960a83cc4657ebe0c9bc462d8f5e2a1.tar.bz2 linux-stable-386a913d4960a83cc4657ebe0c9bc462d8f5e2a1.zip | |
include/linux/list.h: add a macro to test if entry is pointing to the head
commit e130816164e244b692921de49771eeb28205152d upstream.
Add a macro to test if entry is pointing to the head of the list which is
useful in cases like:
list_for_each_entry(pos, &head, member) {
if (cond)
break;
}
if (list_entry_is_head(pos, &head, member))
return -ERRNO;
that allows to avoid additional variable to be added to track if loop has
not been stopped in the middle.
While here, convert list_for_each_entry*() family of macros to use a new one.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lkml.kernel.org/r/20200929134342.51489-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/list.h | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/include/linux/list.h b/include/linux/list.h index de04cc5ed536..d2c12ef7a4e3 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -485,6 +485,15 @@ static inline void list_splice_tail_init(struct list_head *list, pos = n, n = pos->prev) /** + * list_entry_is_head - test if the entry points to the head of the list + * @pos: the type * to cursor + * @head: the head for your list. + * @member: the name of the list_head within the struct. + */ +#define list_entry_is_head(pos, head, member) \ + (&pos->member == (head)) + +/** * list_for_each_entry - iterate over list of given type * @pos: the type * to use as a loop cursor. * @head: the head for your list. @@ -492,7 +501,7 @@ static inline void list_splice_tail_init(struct list_head *list, */ #define list_for_each_entry(pos, head, member) \ for (pos = list_first_entry(head, typeof(*pos), member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = list_next_entry(pos, member)) /** @@ -503,7 +512,7 @@ static inline void list_splice_tail_init(struct list_head *list, */ #define list_for_each_entry_reverse(pos, head, member) \ for (pos = list_last_entry(head, typeof(*pos), member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = list_prev_entry(pos, member)) /** @@ -528,7 +537,7 @@ static inline void list_splice_tail_init(struct list_head *list, */ #define list_for_each_entry_continue(pos, head, member) \ for (pos = list_next_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = list_next_entry(pos, member)) /** @@ -542,7 +551,7 @@ static inline void list_splice_tail_init(struct list_head *list, */ #define list_for_each_entry_continue_reverse(pos, head, member) \ for (pos = list_prev_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = list_prev_entry(pos, member)) /** @@ -554,7 +563,7 @@ static inline void list_splice_tail_init(struct list_head *list, * Iterate over list of given type, continuing from current position. */ #define list_for_each_entry_from(pos, head, member) \ - for (; &pos->member != (head); \ + for (; !list_entry_is_head(pos, head, member); \ pos = list_next_entry(pos, member)) /** @@ -567,7 +576,7 @@ static inline void list_splice_tail_init(struct list_head *list, * Iterate backwards over list of given type, continuing from current position. */ #define list_for_each_entry_from_reverse(pos, head, member) \ - for (; &pos->member != (head); \ + for (; !list_entry_is_head(pos, head, member); \ pos = list_prev_entry(pos, member)) /** @@ -580,7 +589,7 @@ static inline void list_splice_tail_init(struct list_head *list, #define list_for_each_entry_safe(pos, n, head, member) \ for (pos = list_first_entry(head, typeof(*pos), member), \ n = list_next_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = n, n = list_next_entry(n, member)) /** @@ -596,7 +605,7 @@ static inline void list_splice_tail_init(struct list_head *list, #define list_for_each_entry_safe_continue(pos, n, head, member) \ for (pos = list_next_entry(pos, member), \ n = list_next_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = n, n = list_next_entry(n, member)) /** @@ -611,7 +620,7 @@ static inline void list_splice_tail_init(struct list_head *list, */ #define list_for_each_entry_safe_from(pos, n, head, member) \ for (n = list_next_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = n, n = list_next_entry(n, member)) /** @@ -627,7 +636,7 @@ static inline void list_splice_tail_init(struct list_head *list, #define list_for_each_entry_safe_reverse(pos, n, head, member) \ for (pos = list_last_entry(head, typeof(*pos), member), \ n = list_prev_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = n, n = list_prev_entry(n, member)) /** |