diff options
Diffstat (limited to 'lib/raid')
| -rw-r--r-- | lib/raid/xor/xor-core.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/lib/raid/xor/xor-core.c b/lib/raid/xor/xor-core.c index de1d2899490a..2e46b6b83b0a 100644 --- a/lib/raid/xor/xor-core.c +++ b/lib/raid/xor/xor-core.c @@ -46,6 +46,40 @@ xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs) } EXPORT_SYMBOL(xor_blocks); +/** + * xor_gen - generate RAID-style XOR information + * @dest: destination vector + * @srcs: source vectors + * @src_cnt: number of source vectors + * @bytes: length in bytes of each vector + * + * Performs bit-wise XOR operation into @dest for each of the @src_cnt vectors + * in @srcs for a length of @bytes bytes. @src_cnt must be non-zero, and the + * memory pointed to by @dest and each member of @srcs must be at least 64-byte + * aligned. @bytes must be non-zero and a multiple of 512. + * + * Note: for typical RAID uses, @dest either needs to be zeroed, or filled with + * the first disk, which then needs to be removed from @srcs. + */ +void xor_gen(void *dest, void **srcs, unsigned int src_cnt, unsigned int bytes) +{ + unsigned int src_off = 0; + + WARN_ON_ONCE(in_interrupt()); + WARN_ON_ONCE(bytes == 0); + WARN_ON_ONCE(bytes & 511); + + while (src_cnt > 0) { + unsigned int this_cnt = min(src_cnt, MAX_XOR_BLOCKS); + + xor_blocks(this_cnt, bytes, dest, srcs + src_off); + + src_cnt -= this_cnt; + src_off += this_cnt; + } +} +EXPORT_SYMBOL(xor_gen); + /* Set of all registered templates. */ static struct xor_block_template *__initdata template_list; static bool __initdata xor_forced = false; |