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dm-verity FEC: Avoid copying RS parity bytes twice.

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Caching RS parity bytes is already done in fec_decode_bufs() now,
no need to use yet another buffer for conversion to uint16_t.

This patch removes that double copy of RS parity bytes.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
This commit is contained in:
Milan Broz
2024-12-18 13:56:59 +01:00
committed by Mikulas Patocka
parent 6df90c02ba
commit 548c6edbed
1 changed files with 10 additions and 21 deletions
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drivers/md/dm-verity-fec.c
+10 -21
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@@ -39,22 +39,6 @@ static inline u64 fec_interleave(struct dm_verity *v, u64 offset)
return offset + mod * (v->fec->rounds << v->data_dev_block_bits);
}
/*
* Decode an RS block using Reed-Solomon.
*/
static int fec_decode_rs8(struct dm_verity *v, struct dm_verity_fec_io *fio,
u8 *data, u8 *fec, int neras)
{
int i;
uint16_t par[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN];
for (i = 0; i < v->fec->roots; i++)
par[i] = fec[i];
return decode_rs8(fio->rs, data, par, v->fec->rsn, NULL, neras,
fio->erasures, 0, NULL);
}
/*
* Read error-correcting codes for the requested RS block. Returns a pointer
* to the data block. Caller is responsible for releasing buf.
@@ -132,8 +116,9 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,
{
int r, corrected = 0, res;
struct dm_buffer *buf;
unsigned int n, i, offset, par_buf_offset = 0;
u8 *par, *block, par_buf[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN];
unsigned int n, i, j, offset, par_buf_offset = 0;
uint16_t par_buf[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN];
u8 *par, *block;
struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
par = fec_read_parity(v, rsb, block_offset, &offset,
@@ -147,8 +132,11 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,
*/
fec_for_each_buffer_rs_block(fio, n, i) {
block = fec_buffer_rs_block(v, fio, n, i);
memcpy(&par_buf[par_buf_offset], &par[offset], v->fec->roots - par_buf_offset);
res = fec_decode_rs8(v, fio, block, par_buf, neras);
for (j = 0; j < v->fec->roots - par_buf_offset; j++)
par_buf[par_buf_offset + j] = par[offset + j];
/* Decode an RS block using Reed-Solomon */
res = decode_rs8(fio->rs, block, par_buf, v->fec->rsn,
NULL, neras, fio->erasures, 0, NULL);
if (res < 0) {
r = res;
goto error;
@@ -166,7 +154,8 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,
/* Check if parity bytes are split between blocks */
if (offset < v->fec->io_size && (offset + v->fec->roots) > v->fec->io_size) {
par_buf_offset = v->fec->io_size - offset;
memcpy(par_buf, &par[offset], par_buf_offset);
for (j = 0; j < par_buf_offset; j++)
par_buf[j] = par[offset + j];
offset += par_buf_offset;
} else
par_buf_offset = 0;