[PATCH 15/17] bitmap: unify find_bit operations

Yury Norov
2021-08-14T21:20:12Z

bitmap_for_each_{set,clear}_region() are similar to for_each_bit()
macros in include/linux/find.h, but interface and implementation
of them are different.

This patch adds for_each_bitrange() macros and drops unused
bitmap_*_region() API in sake of unification.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Dennis Zhou <dennis@kernel.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
---
drivers/mmc/host/renesas_sdhi_core.c | 2 +-
include/linux/bitmap.h | 33 ----------------
include/linux/find.h | 56 ++++++++++++++++++++++++++++
mm/percpu.c | 20 ++++------
4 files changed, 65 insertions(+), 46 deletions(-)

diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index e49ca0f7fe9a..efd33b1fc467 100644
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/drivers/mmc/host/renesas_sdhi_core.c
@@ -647,7 +647,7 @@ static int renesas_sdhi_select_tuning(struct tmio_mmc_host *host)
* is at least SH_MOBILE_SDHI_MIN_TAP_ROW probes long then use the
* center index as the tap, otherwise bail out.
*/
- bitmap_for_each_set_region(bitmap, rs, re, 0, taps_size) {
+ for_each_set_bitrange(rs, re, bitmap, taps_size) {
if (re - rs > tap_cnt) {
tap_end = re;
tap_start = rs;
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 3f7c6731b203..6938edd457c2 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -55,12 +55,6 @@ struct device;
* bitmap_clear(dst, pos, nbits) Clear specified bit area
* bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area
* bitmap_find_next_zero_area_off(buf, len, pos, n, mask, mask_off) as above
- * bitmap_next_clear_region(map, &start, &end, nbits) Find next clear region
- * bitmap_next_set_region(map, &start, &end, nbits) Find next set region
- * bitmap_for_each_clear_region(map, rs, re, start, end)
- * Iterate over all clear regions
- * bitmap_for_each_set_region(map, rs, re, start, end)
- * Iterate over all set regions
* bitmap_shift_right(dst, src, n, nbits) *dst = *src >> n
* bitmap_shift_left(dst, src, n, nbits) *dst = *src << n
* bitmap_cut(dst, src, first, n, nbits) Cut n bits from first, copy rest
@@ -459,14 +453,6 @@ static inline void bitmap_replace(unsigned long *dst,
__bitmap_replace(dst, old, new, mask, nbits);
}

-static inline void bitmap_next_clear_region(unsigned long *bitmap,
- unsigned int *rs, unsigned int *re,
- unsigned int end)
-{
- *rs = find_next_zero_bit(bitmap, end, *rs);
- *re = find_next_bit(bitmap, end, *rs + 1);
-}
-
static inline void bitmap_next_set_region(unsigned long *bitmap,
unsigned int *rs, unsigned int *re,
unsigned int end)
@@ -475,25 +461,6 @@ static inline void bitmap_next_set_region(unsigned long *bitmap,
*re = find_next_zero_bit(bitmap, end, *rs + 1);
}

-/*
- * Bitmap region iterators. Iterates over the bitmap between [@start, @end).
- * @rs and @re should be integer variables and will be set to start and end
- * index of the current clear or set region.
- */
-#define bitmap_for_each_clear_region(bitmap, rs, re, start, end) \
- for ((rs) = (start), \
- bitmap_next_clear_region((bitmap), &(rs), &(re), (end)); \
- (rs) < (re); \
- (rs) = (re) + 1, \
- bitmap_next_clear_region((bitmap), &(rs), &(re), (end)))
-
-#define bitmap_for_each_set_region(bitmap, rs, re, start, end) \
- for ((rs) = (start), \
- bitmap_next_set_region((bitmap), &(rs), &(re), (end)); \
- (rs) < (re); \
- (rs) = (re) + 1, \
- bitmap_next_set_region((bitmap), &(rs), &(re), (end)))
-
/**
* BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.
* @n: u64 value
diff --git a/include/linux/find.h b/include/linux/find.h
index ae9ed52b52b8..5bb6db213bcb 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -301,6 +301,62 @@ unsigned long find_next_bit_le(const void *addr, unsigned
(bit) < (size); \
(bit) = find_next_zero_bit((addr), (size), (bit) + 1))

+/**
+ * for_each_set_bitrange - iterate over all set bit ranges [b; e)
+ * @b: bit offset of start of current bitrange (first set bit)
+ * @e: bit offset of end of current bitrange (first unset bit)
+ * @addr: bitmap address to base the search on
+ * @size: bitmap size in number of bits
+ */
+#define for_each_set_bitrange(b, e, addr, size) \
+ for ((b) = find_next_bit((addr), (size), 0), \
+ (e) = find_next_zero_bit((addr), (size), (b) + 1); \
+ (b) < (size); \
+ (b) = find_next_bit((addr), (size), (e) + 1), \
+ (e) = find_next_zero_bit((addr), (size), (b) + 1))
+
+/**
+ * for_each_set_bitrange_from - iterate over all set bit ranges [b; e)
+ * @b: bit offset of start of current bitrange (first set bit); must be initialized
+ * @e: bit offset of end of current bitrange (first unset bit)
+ * @addr: bitmap address to base the search on
+ * @size: bitmap size in number of bits
+ */
+#define for_each_set_bitrange_from(b, e, addr, size) \
+ for ((b) = find_next_bit((addr), (size), (b)), \
+ (e) = find_next_zero_bit((addr), (size), (b) + 1); \
+ (b) < (size); \
+ (b) = find_next_bit((addr), (size), (e) + 1), \
+ (e) = find_next_zero_bit((addr), (size), (b) + 1))
+
+/**
+ * for_each_clear_bitrange - iterate over all unset bit ranges [b; e)
+ * @b: bit offset of start of current bitrange (first unset bit)
+ * @e: bit offset of end of current bitrange (first set bit)
+ * @addr: bitmap address to base the search on
+ * @size: bitmap size in number of bits
+ */
+#define for_each_clear_bitrange(b, e, addr, size) \
+ for ((b) = find_next_zero_bit((addr), (size), 0), \
+ (e) = find_next_bit((addr), (size), (b) + 1); \
+ (b) < (size); \
+ (b) = find_next_zero_bit((addr), (size), (e) + 1), \
+ (e) = find_next_bit((addr), (size), (b) + 1))
+
+/**
+ * for_each_clear_bitrange_from - iterate over all unset bit ranges [b; e)
+ * @b: bit offset of start of current bitrange (first set bit); must be initialized
+ * @e: bit offset of end of current bitrange (first unset bit)
+ * @addr: bitmap address to base the search on
+ * @size: bitmap size in number of bits
+ */
+#define for_each_clear_bitrange_from(b, e, addr, size) \
+ for ((b) = find_next_zero_bit((addr), (size), (b)), \
+ (e) = find_next_bit((addr), (size), (b) + 1); \
+ (b) < (size); \
+ (b) = find_next_zero_bit((addr), (size), (e) + 1), \
+ (e) = find_next_bit((addr), (size), (b) + 1))
+
/**
* for_each_set_clump8 - iterate over bitmap for each 8-bit clump with set bits
* @start: bit offset to start search and to store the current iteration offset
diff --git a/mm/percpu.c b/mm/percpu.c
index 8bf8b88446d7..8c16c8e04eee 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -779,7 +779,7 @@ static void pcpu_block_refresh_hint(struct pcpu_chunk *chunk, int index)
{
struct pcpu_block_md *block = chunk->md_blocks + index;
unsigned long *alloc_map = pcpu_index_alloc_map(chunk, index);
- unsigned int rs, re, start; /* region start, region end */
+ unsigned int start, end; /* region start, region end */

/* promote scan_hint to contig_hint */
if (block->scan_hint) {
@@ -795,9 +795,8 @@ static void pcpu_block_refresh_hint(struct pcpu_chunk *chunk, int index)
block->right_free = 0;

/* iterate over free areas and update the contig hints */
- bitmap_for_each_clear_region(alloc_map, rs, re, start,
- PCPU_BITMAP_BLOCK_BITS)
- pcpu_block_update(block, rs, re);
+ for_each_clear_bitrange_from(start, end, alloc_map, PCPU_BITMAP_BLOCK_BITS)
+ pcpu_block_update(block, start, end);
}

/**
@@ -1855,13 +1854,12 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,

/* populate if not all pages are already there */
if (!is_atomic) {
- unsigned int page_start, page_end, rs, re;
+ unsigned int page_end, rs, re;

- page_start = PFN_DOWN(off);
+ rs = PFN_DOWN(off);
page_end = PFN_UP(off + size);

- bitmap_for_each_clear_region(chunk->populated, rs, re,
- page_start, page_end) {
+ for_each_clear_bitrange_from(rs, re, chunk->populated, page_end) {
WARN_ON(chunk->immutable);

ret = pcpu_populate_chunk(chunk, rs, re, pcpu_gfp);
@@ -2017,8 +2015,7 @@ static void pcpu_balance_free(bool empty_only)
list_for_each_entry_safe(chunk, next, &to_free, list) {
unsigned int rs, re;

- bitmap_for_each_set_region(chunk->populated, rs, re, 0,
- chunk->nr_pages) {
+ for_each_set_bitrange(rs, re, chunk->populated, chunk->nr_pages) {
pcpu_depopulate_chunk(chunk, rs, re);
spin_lock_irq(&pcpu_lock);
pcpu_chunk_depopulated(chunk, rs, re);
@@ -2088,8 +2085,7 @@ static void pcpu_balance_populated(void)
continue;

/* @chunk can't go away while pcpu_alloc_mutex is held */
- bitmap_for_each_clear_region(chunk->populated, rs, re, 0,
- chunk->nr_pages) {
+ for_each_clear_bitrange(rs, re, chunk->populated, chunk->nr_pages) {
int nr = min_t(int, re - rs, nr_to_pop);

spin_unlock_irq(&pcpu_lock);
--
2.30.2