Commit 96dfabe7 authored by Eric Biggers's avatar Eric Biggers Committed by Mikulas Patocka
Browse files

dm-verity-fec: simplify deinterleaving 



Since fec_read_bufs() deinterleaves the bytes from 'bbuf' sequentially
starting from 'block_offset', it can just do simple increments instead
of the more complex fec_buffer_rs_index() computation.

Signed-off-by: default avatarEric Biggers <ebiggers@kernel.org>
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
parent 5ef22361

drivers/md/dm-verity-fec.c

+4 −15
Original line number Diff line number Diff line
@@ -44,15 +44,6 @@ static inline u8 *fec_buffer_rs_message(struct dm_verity *v, 
	return &fio->bufs[i][j * v->fec->rs_k];

}



/*

 * Return the index of the current RS message when called inside

 * fec_for_each_buffer_rs_message.

 */

static inline unsigned int fec_buffer_rs_index(unsigned int i, unsigned int j)

{

	return (i << DM_VERITY_FEC_BUF_RS_BITS) + j;

}



/*

 * Decode all RS codewords whose message bytes were loaded into fio->bufs.  Copy

 * the corrected bytes into fio->output starting from block_offset.
@@ -179,7 +170,7 @@ static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io, 
	u64 block, ileaved;

	u8 *bbuf;

	u8 want_digest[HASH_MAX_DIGESTSIZE];

	unsigned int n, k;

	unsigned int n, src_pos;

	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);



	if (neras)
@@ -254,13 +245,11 @@ static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io, 
		 * deinterleave and copy the bytes that fit into bufs,

		 * starting from block_offset

		 */

		src_pos = block_offset;

		fec_for_each_buffer_rs_message(fio, n, j) {

			k = fec_buffer_rs_index(n, j) + block_offset;



			if (k >= v->fec->block_size)

			if (src_pos >= v->fec->block_size)

				goto done;



			fec_buffer_rs_message(v, fio, n, j)[i] = bbuf[k];

			fec_buffer_rs_message(v, fio, n, j)[i] = bbuf[src_pos++];

		}

done:

		dm_bufio_release(buf);