Commit b39b3c81 authored by Eric Biggers's avatar Eric Biggers Committed by Mikulas Patocka
Browse files

dm-verity-fec: pass down index_in_region instead of rsb 



Replace 'rsb', which is a byte index, with 'index_in_region' which is a
block index.  The block index is slightly easier to compute, it matches
what fec_read_bufs() wants, and it avoids the mismatch between the name
and the units of the variable.  ('rsb' stood for "Reed-Solomon block",
but its units were bytes, not blocks.)

fec_decode_bufs() does want it as a byte index when computing
parity_block, but that's easily handled locally.

As long as the parameters to the log messages are being adjusted, also
eliminate the unnecessary casts to 'unsigned long long'.  %llu is the
correct way to print a u64 in the Linux kernel, as documented in
printk-formats.rst.  There's no PRIu64 macro like there is in userspace.

Signed-off-by: default avatarEric Biggers <ebiggers@kernel.org>
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
parent ca21ed40

drivers/md/dm-verity-fec.c

+26 −21
Original line number Diff line number Diff line
@@ -49,7 +49,7 @@ static inline u8 *fec_buffer_rs_message(struct dm_verity *v, 
 * the corrected bytes into fio->output starting from out_pos.

 */

static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,

			   struct dm_verity_fec_io *fio, u64 rsb,

			   struct dm_verity_fec_io *fio, u64 index_in_region,

			   int target_region, unsigned int out_pos, int neras)

{

	int r, corrected = 0, res;
@@ -67,14 +67,16 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io, 
	 * block_size is always a power of 2, but roots might not be.  Note that

	 * when it's not, a codeword's parity bytes can span a block boundary.

	 */

	parity_block = (rsb + out_pos) * v->fec->roots;

	parity_block = ((index_in_region << v->data_dev_block_bits) + out_pos) *

		       v->fec->roots;

	parity_pos = parity_block & (v->fec->block_size - 1);

	parity_block >>= v->data_dev_block_bits;

	par = dm_bufio_read_with_ioprio(v->fec->bufio, parity_block, &buf,

					bio->bi_ioprio);

	if (IS_ERR(par)) {

		DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",

		      v->data_dev->name, rsb, parity_block, PTR_ERR(par));

		      v->data_dev->name, index_in_region, parity_block,

		      PTR_ERR(par));

		return PTR_ERR(par);

	}
@@ -103,8 +105,8 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io, 
							bio->bi_ioprio);

			if (IS_ERR(par)) {

				DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",

				      v->data_dev->name, rsb, parity_block,

				      PTR_ERR(par));

				      v->data_dev->name, index_in_region,

				      parity_block, PTR_ERR(par));

				return PTR_ERR(par);

			}

			for (; j < v->fec->roots; j++)
@@ -132,10 +134,10 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io, 


	if (r < 0 && neras)

		DMERR_LIMIT("%s: FEC %llu: failed to correct: %d",

			    v->data_dev->name, (unsigned long long)rsb, r);

			    v->data_dev->name, index_in_region, r);

	else if (r > 0)

		DMWARN_LIMIT("%s: FEC %llu: corrected %d errors",

			     v->data_dev->name, (unsigned long long)rsb, r);

			     v->data_dev->name, index_in_region, r);



	return r;

}
@@ -158,14 +160,14 @@ static int fec_is_erasure(struct dm_verity *v, struct dm_verity_io *io, 
 * fits into buffers. Check for erasure locations if @neras is non-NULL.

 */

static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io,

			 u64 rsb, unsigned int out_pos, int *neras)

			 u64 index_in_region, unsigned int out_pos, int *neras)

{

	bool is_zero;

	int i, j;

	struct dm_buffer *buf;

	struct dm_bufio_client *bufio;

	struct dm_verity_fec_io *fio = io->fec_io;

	u64 block, ileaved;

	u64 block;

	u8 *bbuf;

	u8 want_digest[HASH_MAX_DIGESTSIZE];

	unsigned int n, src_pos;
@@ -182,8 +184,7 @@ static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io, 
	 * interleave contents to available bufs

	 */

	for (i = 0; i < v->fec->rs_k; i++) {

		ileaved = rsb + i * (v->fec->region_blocks << v->data_dev_block_bits);

		block = ileaved >> v->data_dev_block_bits;

		block = i * v->fec->region_blocks + index_in_region;

		bufio = v->fec->data_bufio;



		if (block >= v->data_blocks) {
@@ -203,9 +204,8 @@ static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io, 
		bbuf = dm_bufio_read_with_ioprio(bufio, block, &buf, bio->bi_ioprio);

		if (IS_ERR(bbuf)) {

			DMWARN_LIMIT("%s: FEC %llu: read failed (%llu): %ld",

				     v->data_dev->name,

				     (unsigned long long)rsb,

				     (unsigned long long)block, PTR_ERR(bbuf));

				     v->data_dev->name, index_in_region, block,

				     PTR_ERR(bbuf));



			/* assume the block is corrupted */

			if (neras && *neras <= v->fec->roots)
@@ -312,11 +312,16 @@ static int fec_decode(struct dm_verity *v, struct dm_verity_io *io, 
{

	int r, neras = 0;

	unsigned int target_region, out_pos;

	u64 rsb;

	u64 index_in_region;



	target_region = div64_u64_rem(

		target_block << v->data_dev_block_bits,

		v->fec->region_blocks << v->data_dev_block_bits, &rsb);

	/*

	 * Compute 'target_region', the index of the region the target block is

	 * in; and 'index_in_region', the index of the target block within its

	 * region.  The latter value is also the index within its region of each

	 * message block that shares its RS codewords with the target block.

	 */

	target_region = div64_u64_rem(target_block, v->fec->region_blocks,

				      &index_in_region);

	if (WARN_ON_ONCE(target_region >= v->fec->rs_k))

		/* target_block is out-of-bounds.  Should never happen. */

		return -EIO;
@@ -324,12 +329,12 @@ static int fec_decode(struct dm_verity *v, struct dm_verity_io *io, 
	for (out_pos = 0; out_pos < v->fec->block_size;) {

		fec_init_bufs(v, fio);



		r = fec_read_bufs(v, io, rsb, out_pos,

		r = fec_read_bufs(v, io, index_in_region, out_pos,

				  use_erasures ? &neras : NULL);

		if (unlikely(r < 0))

			return r;



		r = fec_decode_bufs(v, io, fio, rsb, target_region,

		r = fec_decode_bufs(v, io, fio, index_in_region, target_region,

				    out_pos, neras);

		if (r < 0)

			return r;
@@ -344,7 +349,7 @@ static int fec_decode(struct dm_verity *v, struct dm_verity_io *io, 


	if (memcmp(io->tmp_digest, want_digest, v->digest_size)) {

		DMERR_LIMIT("%s: FEC %llu: failed to correct (%d erasures)",

			    v->data_dev->name, (unsigned long long)rsb, neras);

			    v->data_dev->name, index_in_region, neras);

		return -EILSEQ;

	}