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Commit ff3af92b authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm crypt: use shifts instead of sector_div 



sector_div is very slow, so we introduce a variable sector_shift and
use shift instead of sector_div.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent c2bcb2b7

drivers/md/dm-crypt.c

+10 −7
Original line number Diff line number Diff line
@@ -172,7 +172,8 @@ struct crypt_config { 
	} iv_gen_private;

	sector_t iv_offset;

	unsigned int iv_size;

	unsigned int sector_size;

	unsigned short int sector_size;

	unsigned char sector_shift;



	/* ESSIV: struct crypto_cipher *essiv_tfm */

	void *iv_private;
@@ -1062,7 +1063,7 @@ static int crypt_convert_block_aead(struct crypt_config *cc, 
	dmreq = dmreq_of_req(cc, req);

	dmreq->iv_sector = ctx->cc_sector;

	if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))

		sector_div(dmreq->iv_sector, cc->sector_size >> SECTOR_SHIFT);

		dmreq->iv_sector >>= cc->sector_shift;

	dmreq->ctx = ctx;



	*org_tag_of_dmreq(cc, dmreq) = tag_offset;
@@ -1155,7 +1156,7 @@ static int crypt_convert_block_skcipher(struct crypt_config *cc, 
	dmreq = dmreq_of_req(cc, req);

	dmreq->iv_sector = ctx->cc_sector;

	if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))

		sector_div(dmreq->iv_sector, cc->sector_size >> SECTOR_SHIFT);

		dmreq->iv_sector >>= cc->sector_shift;

	dmreq->ctx = ctx;



	*org_tag_of_dmreq(cc, dmreq) = tag_offset;
@@ -1290,7 +1291,7 @@ static int crypt_convert(struct crypt_config *cc, 
			 struct convert_context *ctx)

{

	unsigned int tag_offset = 0;

	unsigned int sector_step = cc->sector_size / (1 << SECTOR_SHIFT);

	unsigned int sector_step = cc->sector_size >> SECTOR_SHIFT;

	int r;



	atomic_set(&ctx->cc_pending, 1);
@@ -2575,13 +2576,14 @@ static int crypt_ctr_optional(struct dm_target *ti, unsigned int argc, char **ar 
			cc->cipher_auth = kstrdup(sval, GFP_KERNEL);

			if (!cc->cipher_auth)

				return -ENOMEM;

		} else if (sscanf(opt_string, "sector_size:%u%c", &cc->sector_size, &dummy) == 1) {

		} else if (sscanf(opt_string, "sector_size:%hu%c", &cc->sector_size, &dummy) == 1) {

			if (cc->sector_size < (1 << SECTOR_SHIFT) ||

			    cc->sector_size > 4096 ||

			    (1 << ilog2(cc->sector_size) != cc->sector_size)) {

			    (cc->sector_size & (cc->sector_size - 1))) {

				ti->error = "Invalid feature value for sector_size";

				return -EINVAL;

			}

			cc->sector_shift = __ffs(cc->sector_size) - SECTOR_SHIFT;

		} else if (!strcasecmp(opt_string, "iv_large_sectors"))

			set_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags);

		else {
@@ -2625,6 +2627,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) 
	}

	cc->key_size = key_size;

	cc->sector_size = (1 << SECTOR_SHIFT);

	cc->sector_shift = 0;



	ti->private = cc;
@@ -2870,7 +2873,7 @@ static void crypt_status(struct dm_target *ti, status_type_t type, 
		num_feature_args += !!ti->num_discard_bios;

		num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags);

		num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);

		num_feature_args += (cc->sector_size != (1 << SECTOR_SHIFT)) ? 1 : 0;

		num_feature_args += cc->sector_size != (1 << SECTOR_SHIFT);

		num_feature_args += test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags);

		if (cc->on_disk_tag_size)

			num_feature_args++;