[PATCH 01/10] lib/sort: Add priv pointer to swap function

Jiri Olsa
2022-02-22T17:06:40Z

Adding support to have priv pointer in swap callback function.

Following the initial change on cmp callback functions [1]
and adding SWAP_WRAPPER macro to identify sort call of sort_r.

Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
[1] 4333fb96ca10 ("media: lib/sort.c: implement sort() variant taking context argument")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
include/linux/sort.h | 2 +-
include/linux/types.h | 1 +
lib/sort.c | 40 ++++++++++++++++++++++++++++++----------
3 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/include/linux/sort.h b/include/linux/sort.h
index b5898725fe9d..e163287ac6c1 100644
--- a/include/linux/sort.h
+++ b/include/linux/sort.h
@@ -6,7 +6,7 @@

void sort_r(void *base, size_t num, size_t size,
cmp_r_func_t cmp_func,
- swap_func_t swap_func,
+ swap_r_func_t swap_func,
const void *priv);

void sort(void *base, size_t num, size_t size,
diff --git a/include/linux/types.h b/include/linux/types.h
index ac825ad90e44..ea8cf60a8a79 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -226,6 +226,7 @@ struct callback_head {
typedef void (*rcu_callback_t)(struct rcu_head *head);
typedef void (*call_rcu_func_t)(struct rcu_head *head, rcu_callback_t func);

+typedef void (*swap_r_func_t)(void *a, void *b, int size, const void *priv);
typedef void (*swap_func_t)(void *a, void *b, int size);

typedef int (*cmp_r_func_t)(const void *a, const void *b, const void *priv);
diff --git a/lib/sort.c b/lib/sort.c
index aa18153864d2..b399bf10d675 100644
--- a/lib/sort.c
+++ b/lib/sort.c
@@ -122,16 +122,27 @@ static void swap_bytes(void *a, void *b, size_t n)
* a pointer, but small integers make for the smallest compare
* instructions.
*/
-#define SWAP_WORDS_64 (swap_func_t)0
-#define SWAP_WORDS_32 (swap_func_t)1
-#define SWAP_BYTES (swap_func_t)2
+#define SWAP_WORDS_64 (swap_r_func_t)0
+#define SWAP_WORDS_32 (swap_r_func_t)1
+#define SWAP_BYTES (swap_r_func_t)2
+#define SWAP_WRAPPER (swap_r_func_t)3
+
+struct wrapper {
+ cmp_func_t cmp;
+ swap_func_t swap;
+};

/*
* The function pointer is last to make tail calls most efficient if the
* compiler decides not to inline this function.
*/
-static void do_swap(void *a, void *b, size_t size, swap_func_t swap_func)
+static void do_swap(void *a, void *b, size_t size, swap_r_func_t swap_func, const void *priv)
{
+ if (swap_func == SWAP_WRAPPER) {
+ ((const struct wrapper *)priv)->swap(a, b, (int)size);
+ return;
+ }
+
if (swap_func == SWAP_WORDS_64)
swap_words_64(a, b, size);
else if (swap_func == SWAP_WORDS_32)
@@ -139,7 +150,7 @@ static void do_swap(void *a, void *b, size_t size, swap_func_t swap_func)
else if (swap_func == SWAP_BYTES)
swap_bytes(a, b, size);
else
- swap_func(a, b, (int)size);
+ swap_func(a, b, (int)size, priv);
}

#define _CMP_WRAPPER ((cmp_r_func_t)0L)
@@ -147,7 +158,7 @@ static void do_swap(void *a, void *b, size_t size, swap_func_t swap_func)
static int do_cmp(const void *a, const void *b, cmp_r_func_t cmp, const void *priv)
{
if (cmp == _CMP_WRAPPER)
- return ((cmp_func_t)(priv))(a, b);
+ return ((const struct wrapper *)priv)->cmp(a, b);
return cmp(a, b, priv);
}

@@ -198,7 +209,7 @@ static size_t parent(size_t i, unsigned int lsbit, size_t size)
*/
void sort_r(void *base, size_t num, size_t size,
cmp_r_func_t cmp_func,
- swap_func_t swap_func,
+ swap_r_func_t swap_func,
const void *priv)
{
/* pre-scale counters for performance */
@@ -208,6 +219,10 @@ void sort_r(void *base, size_t num, size_t size,
if (!a) /* num < 2 || size == 0 */
return;

+ /* called from 'sort' without swap function, let's pick the default */
+ if (swap_func == SWAP_WRAPPER && !((struct wrapper *)priv)->swap)
+ swap_func = NULL;
+
if (!swap_func) {
if (is_aligned(base, size, 8))
swap_func = SWAP_WORDS_64;
@@ -230,7 +245,7 @@ void sort_r(void *base, size_t num, size_t size,
if (a) /* Building heap: sift down --a */
a -= size;
else if (n -= size) /* Sorting: Extract root to --n */
- do_swap(base, base + n, size, swap_func);
+ do_swap(base, base + n, size, swap_func, priv);
else /* Sort complete */
break;

@@ -257,7 +272,7 @@ void sort_r(void *base, size_t num, size_t size,
c = b; /* Where "a" belongs */
while (b != a) { /* Shift it into place */
b = parent(b, lsbit, size);
- do_swap(base + b, base + c, size, swap_func);
+ do_swap(base + b, base + c, size, swap_func, priv);
}
}
}
@@ -267,6 +282,11 @@ void sort(void *base, size_t num, size_t size,
cmp_func_t cmp_func,
swap_func_t swap_func)
{
- return sort_r(base, num, size, _CMP_WRAPPER, swap_func, cmp_func);
+ struct wrapper w = {
+ .cmp = cmp_func,
+ .swap = swap_func,
+ };
+
+ return sort_r(base, num, size, _CMP_WRAPPER, SWAP_WRAPPER, &w);
}
EXPORT_SYMBOL(sort);
--
2.35.1