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author | John Sanpe <sanpeqf@gmail.com> | 2023-12-05 18:58:37 +0300 |
---|---|---|
committer | Namjae Jeon <linkinjeon@kernel.org> | 2024-01-08 15:57:21 +0300 |
commit | 7423546040194e0e74fcfedd089a8b2720fcfc6e (patch) | |
tree | 850f350b77bf9e1a3adb9c0f26d980704c8a13ad /fs/exfat/balloc.c | |
parent | 0dd3ee31125508cd67f7e7172247f05b7fd1753a (diff) | |
download | linux-7423546040194e0e74fcfedd089a8b2720fcfc6e.tar.xz |
exfat: using hweight instead of internal logic
Replace the internal table lookup algorithm with the hweight
library, which has instruction set acceleration capabilities.
Use it to increase the length of a single calculation of
the exfat_find_free_bitmap function to the long type.
Signed-off-by: John Sanpe <sanpeqf@gmail.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Diffstat (limited to 'fs/exfat/balloc.c')
-rw-r--r-- | fs/exfat/balloc.c | 48 |
1 files changed, 21 insertions, 27 deletions
diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c index e918decb3735..3e3e9e4cce2f 100644 --- a/fs/exfat/balloc.c +++ b/fs/exfat/balloc.c @@ -5,11 +5,22 @@ #include <linux/blkdev.h> #include <linux/slab.h> +#include <linux/bitmap.h> #include <linux/buffer_head.h> #include "exfat_raw.h" #include "exfat_fs.h" +#if BITS_PER_LONG == 32 +#define __le_long __le32 +#define lel_to_cpu(A) le32_to_cpu(A) +#elif BITS_PER_LONG == 64 +#define __le_long __le64 +#define lel_to_cpu(A) le64_to_cpu(A) +#else +#error "BITS_PER_LONG not 32 or 64" +#endif + static const unsigned char free_bit[] = { 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/* 0 ~ 19*/ 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3,/* 20 ~ 39*/ @@ -26,22 +37,6 @@ static const unsigned char free_bit[] = { 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 /*240 ~ 254*/ }; -static const unsigned char used_bit[] = { - 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3,/* 0 ~ 19*/ - 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4,/* 20 ~ 39*/ - 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5,/* 40 ~ 59*/ - 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,/* 60 ~ 79*/ - 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4,/* 80 ~ 99*/ - 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,/*100 ~ 119*/ - 4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4,/*120 ~ 139*/ - 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,/*140 ~ 159*/ - 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5,/*160 ~ 179*/ - 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4, 5,/*180 ~ 199*/ - 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6,/*200 ~ 219*/ - 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,/*220 ~ 239*/ - 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8 /*240 ~ 255*/ -}; - /* * Allocation Bitmap Management Functions */ @@ -244,25 +239,24 @@ int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count) unsigned int count = 0; unsigned int i, map_i = 0, map_b = 0; unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi); - unsigned int last_mask = total_clus & BITS_PER_BYTE_MASK; - unsigned char clu_bits; - const unsigned char last_bit_mask[] = {0, 0b00000001, 0b00000011, - 0b00000111, 0b00001111, 0b00011111, 0b00111111, 0b01111111}; + unsigned int last_mask = total_clus & (BITS_PER_LONG - 1); + unsigned long *bitmap, clu_bits; total_clus &= ~last_mask; - for (i = 0; i < total_clus; i += BITS_PER_BYTE) { - clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b); - count += used_bit[clu_bits]; - if (++map_b >= (unsigned int)sb->s_blocksize) { + for (i = 0; i < total_clus; i += BITS_PER_LONG) { + bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b); + count += hweight_long(*bitmap); + map_b += sizeof(long); + if (map_b >= (unsigned int)sb->s_blocksize) { map_i++; map_b = 0; } } if (last_mask) { - clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b); - clu_bits &= last_bit_mask[last_mask]; - count += used_bit[clu_bits]; + bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b); + clu_bits = lel_to_cpu(*(__le_long *)bitmap); + count += hweight_long(clu_bits & BITMAP_LAST_WORD_MASK(last_mask)); } *ret_count = count; |