bcache: update min_heap_callbacks to use default builtin swap

Replace the swp function pointer in the min_heap_callbacks of bcache with
NULL, allowing direct usage of the default builtin swap implementation. 
This modification simplifies the code and improves performance by removing
unnecessary function indirection.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kuan-Wei Chiu <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Ching-Chun (Jim) Huang <[email protected]>
Cc: Coly Li <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: "Liang, Kan" <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Sakai <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: visitorckw

drivers/md/bcache/alloc.c

@@ -189,23 +189,16 @@ static inline bool new_bucket_min_cmp(const void *l, const void *r, void *args)
 	return new_bucket_prio(ca, *lhs) < new_bucket_prio(ca, *rhs);
 }
 
-static inline void new_bucket_swap(void *l, void *r, void __always_unused *args)
-{
-	struct bucket **lhs = l, **rhs = r;
-
-	swap(*lhs, *rhs);
-}
-
 static void invalidate_buckets_lru(struct cache *ca)
 {
 	struct bucket *b;
 	const struct min_heap_callbacks bucket_max_cmp_callback = {
 		.less = new_bucket_max_cmp,
-		.swp = new_bucket_swap,
+		.swp = NULL,
 	};
 	const struct min_heap_callbacks bucket_min_cmp_callback = {
 		.less = new_bucket_min_cmp,
-		.swp = new_bucket_swap,
+		.swp = NULL,
 	};
 
 	ca->heap.nr = 0;

drivers/md/bcache/bset.c

@@ -1093,14 +1093,6 @@ static inline bool new_btree_iter_cmp(const void *l, const void *r, void __alway
 	return bkey_cmp(_l->k, _r->k) <= 0;
 }
 
-static inline void new_btree_iter_swap(void *iter1, void *iter2, void __always_unused *args)
-{
-	struct btree_iter_set *_iter1 = iter1;
-	struct btree_iter_set *_iter2 = iter2;
-
-	swap(*_iter1, *_iter2);
-}
-
 static inline bool btree_iter_end(struct btree_iter *iter)
 {
 	return !iter->heap.nr;
@@ -1111,7 +1103,7 @@ void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
 {
 	const struct min_heap_callbacks callbacks = {
 		.less = new_btree_iter_cmp,
-		.swp = new_btree_iter_swap,
+		.swp = NULL,
 	};
 
 	if (k != end)
@@ -1157,7 +1149,7 @@ static inline struct bkey *__bch_btree_iter_next(struct btree_iter *iter,
 	struct bkey *ret = NULL;
 	const struct min_heap_callbacks callbacks = {
 		.less = cmp,
-		.swp = new_btree_iter_swap,
+		.swp = NULL,
 	};
 
 	if (!btree_iter_end(iter)) {
@@ -1231,7 +1223,7 @@ static void btree_mergesort(struct btree_keys *b, struct bset *out,
 		: bch_ptr_invalid;
 	const struct min_heap_callbacks callbacks = {
 		.less = b->ops->sort_cmp,
-		.swp = new_btree_iter_swap,
+		.swp = NULL,
 	};
 
 	/* Heapify the iterator, using our comparison function */

drivers/md/bcache/extents.c

@@ -266,20 +266,12 @@ static bool new_bch_extent_sort_cmp(const void *l, const void *r, void __always_
 	return !(c ? c > 0 : _l->k < _r->k);
 }
 
-static inline void new_btree_iter_swap(void *iter1, void *iter2, void __always_unused *args)
-{
-	struct btree_iter_set *_iter1 = iter1;
-	struct btree_iter_set *_iter2 = iter2;
-
-	swap(*_iter1, *_iter2);
-}
-
 static struct bkey *bch_extent_sort_fixup(struct btree_iter *iter,
 					  struct bkey *tmp)
 {
 	const struct min_heap_callbacks callbacks = {
 		.less = new_bch_extent_sort_cmp,
-		.swp = new_btree_iter_swap,
+		.swp = NULL,
 	};
 	while (iter->heap.nr > 1) {
 		struct btree_iter_set *top = iter->heap.data, *i = top + 1;

drivers/md/bcache/movinggc.c

@@ -190,14 +190,6 @@ static bool new_bucket_cmp(const void *l, const void *r, void __always_unused *a
 	return GC_SECTORS_USED(*_l) >= GC_SECTORS_USED(*_r);
 }
 
-static void new_bucket_swap(void *l, void *r, void __always_unused *args)
-{
-	struct bucket **_l = l;
-	struct bucket **_r = r;
-
-	swap(*_l, *_r);
-}
-
 static unsigned int bucket_heap_top(struct cache *ca)
 {
 	struct bucket *b;
@@ -212,7 +204,7 @@ void bch_moving_gc(struct cache_set *c)
 	unsigned long sectors_to_move, reserve_sectors;
 	const struct min_heap_callbacks callbacks = {
 		.less = new_bucket_cmp,
-		.swp = new_bucket_swap,
+		.swp = NULL,
 	};
 
 	if (!c->copy_gc_enabled)