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-   -   dm-crypt: move temporary values to stack (http://www.linux-archive.org/device-mapper-development/696236-dm-crypt-move-temporary-values-stack.html)

Mikulas Patocka 08-21-2012 09:09 AM

dm-crypt: move temporary values to stack
 
Structure dm_crypt_io contains some values that are used only temporarily.
Move these values to a structure dm_crypt_position that is allocated on stack.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
---
drivers/md/dm-crypt.c | 89 +++++++++++++++++++++++--------------------------
1 file changed, 42 insertions(+), 47 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 097171b..9316630 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -45,11 +45,6 @@ struct dm_crypt_io {
struct work_struct work;

struct bio *bio_out;
- unsigned int offset_in;
- unsigned int offset_out;
- unsigned int idx_in;
- unsigned int idx_out;
- sector_t cc_sector;
atomic_t cc_pending;

int error;
@@ -625,17 +620,6 @@ static struct crypt_iv_operations crypt_iv_lmk_ops = {
.post = crypt_iv_lmk_post
};

-static void crypt_convert_init(struct dm_crypt_io *io, struct bio *bio_out)
-{
- struct crypt_config *cc = io->cc;
- io->bio_out = bio_out;
- io->offset_in = 0;
- io->offset_out = 0;
- io->idx_in = io->base_bio->bi_idx;
- io->idx_out = bio_out->bi_idx;
- io->cc_sector = io->sector + cc->iv_offset;
-}
-
static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
struct ablkcipher_request *req)
{
@@ -728,11 +712,20 @@ pop_from_list:
return 0;
}

+struct dm_crypt_position {
+ unsigned int offset_in;
+ unsigned int offset_out;
+ unsigned int idx_in;
+ unsigned int idx_out;
+ sector_t cc_sector;
+};
+
static struct ablkcipher_request *crypt_alloc_req(struct dm_crypt_io *io,
+ struct dm_crypt_position *pos,
gfp_t gfp_mask)
{
struct crypt_config *cc = io->cc;
- unsigned key_index = io->cc_sector & (cc->tfms_count - 1);
+ unsigned key_index = pos->cc_sector & (cc->tfms_count - 1);
struct ablkcipher_request *req = mempool_alloc(cc->req_pool, gfp_mask);
if (!req)
return NULL;
@@ -771,11 +764,12 @@ static void crypt_dec_cc_pending(struct dm_crypt_io *io)

static int crypt_convert_block(struct dm_crypt_io *io,
struct ablkcipher_request *req,
+ struct dm_crypt_position *pos,
struct list_head *batch)
{
struct crypt_config *cc = io->cc;
- struct bio_vec *bv_in = bio_iovec_idx(io->base_bio, io->idx_in);
- struct bio_vec *bv_out = bio_iovec_idx(io->bio_out, io->idx_out);
+ struct bio_vec *bv_in = bio_iovec_idx(io->base_bio, pos->idx_in);
+ struct bio_vec *bv_out = bio_iovec_idx(io->bio_out, pos->idx_out);
struct dm_crypt_request *dmreq;
u8 *iv;
int r;
@@ -783,26 +777,26 @@ static int crypt_convert_block(struct dm_crypt_io *io,
dmreq = dmreq_of_req(cc, req);
iv = iv_of_dmreq(cc, dmreq);

- dmreq->iv_sector = io->cc_sector;
+ dmreq->iv_sector = pos->cc_sector;
dmreq->io = io;
sg_init_table(&dmreq->sg_in, 1);
sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
- bv_in->bv_offset + io->offset_in);
+ bv_in->bv_offset + pos->offset_in);

sg_init_table(&dmreq->sg_out, 1);
sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
- bv_out->bv_offset + io->offset_out);
+ bv_out->bv_offset + pos->offset_out);

- io->offset_in += 1 << SECTOR_SHIFT;
- if (io->offset_in >= bv_in->bv_len) {
- io->offset_in = 0;
- io->idx_in++;
+ pos->offset_in += 1 << SECTOR_SHIFT;
+ if (pos->offset_in >= bv_in->bv_len) {
+ pos->offset_in = 0;
+ pos->idx_in++;
}

- io->offset_out += 1 << SECTOR_SHIFT;
- if (io->offset_out >= bv_out->bv_len) {
- io->offset_out = 0;
- io->idx_out++;
+ pos->offset_out += 1 << SECTOR_SHIFT;
+ if (pos->offset_out >= bv_out->bv_len) {
+ pos->offset_out = 0;
+ pos->idx_out++;
}

if (cc->iv_gen_ops) {
@@ -822,17 +816,25 @@ static int crypt_convert_block(struct dm_crypt_io *io,
/*
* Encrypt / decrypt data from one bio to another one (can be the same one)
*/
-static void crypt_convert(struct dm_crypt_io *io)
+static void crypt_convert(struct dm_crypt_io *io, struct bio *bio_out)
{
struct crypt_config *cc = io->cc;
LIST_HEAD(batch);
unsigned batch_count = 0;
+ struct dm_crypt_position pos;
+
+ io->bio_out = bio_out;
+ pos.offset_in = 0;
+ pos.offset_out = 0;
+ pos.idx_in = io->base_bio->bi_idx;
+ pos.idx_out = bio_out->bi_idx;
+ pos.cc_sector = io->sector + cc->iv_offset;

atomic_set(&io->cc_pending, 1);

while (1) {
int r;
- struct ablkcipher_request *req = crypt_alloc_req(io, GFP_NOWAIT);
+ struct ablkcipher_request *req = crypt_alloc_req(io, &pos, GFP_NOWAIT);
if (!req) {
/*
* We must flush our request queue before we attempt
@@ -840,10 +842,10 @@ static void crypt_convert(struct dm_crypt_io *io)
*/
batch_count = 0;
crypt_flush_batch(cc, &batch);
- req = crypt_alloc_req(io, GFP_NOIO);
+ req = crypt_alloc_req(io, &pos, GFP_NOIO);
}

- r = crypt_convert_block(io, req, &batch);
+ r = crypt_convert_block(io, req, &pos, &batch);
if (unlikely(r < 0)) {
crypt_flush_batch(cc, &batch);
io->error = -EIO;
@@ -851,10 +853,10 @@ static void crypt_convert(struct dm_crypt_io *io)
return;
}

- io->sector++;
-
- if (io->idx_in < io->base_bio->bi_vcnt &&
- io->idx_out < io->bio_out->bi_vcnt) {
+ pos.cc_sector++;
+
+ if (pos.idx_in < io->base_bio->bi_vcnt &&
+ pos.idx_out < io->bio_out->bi_vcnt) {
atomic_inc(&io->cc_pending);
if (unlikely(++batch_count >= DMREQ_PUSH_BATCH)) {
batch_count = 0;
@@ -1080,9 +1082,6 @@ static void kcryptd_io_write(struct work_struct *work)
return;
}

- /* crypt_convert should have filled the clone bio */
- BUG_ON(io->idx_out < clone->bi_vcnt);
-
clone->bi_sector = cc->start + io->sector;

generic_make_request(clone);
@@ -1107,16 +1106,12 @@ static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
return;
}

- crypt_convert_init(io, clone);
-
- crypt_convert(io);
+ crypt_convert(io, clone);
}

static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
{
- crypt_convert_init(io, io->base_bio);
-
- crypt_convert(io);
+ crypt_convert(io, io->base_bio);
}

static void kcryptd_async_done(struct crypto_async_request *async_req,
--
1.7.10.4

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