This patch changes crypt_alloc_buffer so that it always allocates pages for
a full request.
This change enables further simplification and removing of one refcounts
in the next patches.
Note: the next patch is needed to fix a theoretical deadlock
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/md/dm-crypt.c | 139 ++++++++++----------------------------------------
1 file changed, 30 insertions(+), 109 deletions(-)
Index: linux-3.14/drivers/md/dm-crypt.c
===================================================================
--- linux-3.14.orig/drivers/md/dm-crypt.c 2014-04-04 20:48:50.000000000 +0200
+++ linux-3.14/drivers/md/dm-crypt.c 2014-04-04 20:57:36.000000000 +0200
@@ -58,7 +58,6 @@ struct dm_crypt_io {
atomic_t io_pending;
int error;
sector_t sector;
- struct dm_crypt_io *base_io;
} CRYPTO_MINALIGN_ATTR;
struct dm_crypt_request {
@@ -172,7 +171,6 @@ struct crypt_config {
};
#define MIN_IOS 16
-#define MIN_POOL_PAGES 32
static struct kmem_cache *_crypt_io_pool;
@@ -951,14 +949,13 @@ static int crypt_convert(struct crypt_co
return 0;
}
+static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone);
+
/*
* Generate a new unfragmented bio with the given size
* This should never violate the device limitations
- * May return a smaller bio when running out of pages, indicated by
- * *out_of_pages set to 1.
*/
-static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
- unsigned *out_of_pages)
+static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
{
struct crypt_config *cc = io->cc;
struct bio *clone;
@@ -966,41 +963,27 @@ static struct bio *crypt_alloc_buffer(st
gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
unsigned i, len;
struct page *page;
+ struct bio_vec *bvec;
clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
if (!clone)
return NULL;
clone_init(io, clone);
- *out_of_pages = 0;
for (i = 0; i < nr_iovecs; i++) {
page = mempool_alloc(cc->page_pool, gfp_mask);
- if (!page) {
- *out_of_pages = 1;
- break;
- }
-
- /*
- * If additional pages cannot be allocated without waiting,
- * return a partially-allocated bio. The caller will then try
- * to allocate more bios while submitting this partial bio.
- */
- gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
- if (!bio_add_page(clone, page, len, 0)) {
- mempool_free(page, cc->page_pool);
- break;
- }
+ bvec = &clone->bi_io_vec[clone->bi_vcnt++];
+ bvec->bv_page = page;
+ bvec->bv_len = len;
+ bvec->bv_offset = 0;
- size -= len;
- }
+ clone->bi_iter.bi_size += len;
- if (!clone->bi_iter.bi_size) {
- bio_put(clone);
- return NULL;
+ size -= len;
}
return clone;
@@ -1025,7 +1008,6 @@ static void crypt_io_init(struct dm_cryp
io->base_bio = bio;
io->sector = sector;
io->error = 0;
- io->base_io = NULL;
io->ctx.req = NULL;
atomic_set(&io->io_pending, 0);
}
@@ -1038,13 +1020,11 @@ static void crypt_inc_pending(struct dm_
/*
* One of the bios was finished. Check for completion of
* the whole request and correctly clean up the buffer.
- * If base_io is set, wait for the last fragment to complete.
*/
static void crypt_dec_pending(struct dm_crypt_io *io)
{
struct crypt_config *cc = io->cc;
struct bio *base_bio = io->base_bio;
- struct dm_crypt_io *base_io = io->base_io;
int error = io->error;
if (!atomic_dec_and_test(&io->io_pending))
@@ -1055,13 +1035,7 @@ static void crypt_dec_pending(struct dm_
if (io != dm_per_bio_data(base_bio, cc->per_bio_data_size))
mempool_free(io, cc->io_pool);
- if (likely(!base_io))
- bio_endio(base_bio, error);
- else {
- if (error && !base_io->error)
- base_io->error = error;
- crypt_dec_pending(base_io);
- }
+ bio_endio(base_bio, error);
}
/*
@@ -1197,10 +1171,7 @@ static void kcryptd_crypt_write_convert(
{
struct crypt_config *cc = io->cc;
struct bio *clone;
- struct dm_crypt_io *new_io;
int crypt_finished;
- unsigned out_of_pages = 0;
- unsigned remaining = io->base_bio->bi_iter.bi_size;
sector_t sector = io->sector;
int r;
@@ -1210,80 +1181,30 @@ static void kcryptd_crypt_write_convert(
crypt_inc_pending(io);
crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
- /*
- * The allocated buffers can be smaller than the whole bio,
- * so repeat the whole process until all the data can be handled.
- */
- while (remaining) {
- clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
- if (unlikely(!clone)) {
- io->error = -ENOMEM;
- break;
- }
-
- io->ctx.bio_out = clone;
- io->ctx.iter_out = clone->bi_iter;
-
- remaining -= clone->bi_iter.bi_size;
- sector += bio_sectors(clone);
-
- crypt_inc_pending(io);
-
- r = crypt_convert(cc, &io->ctx);
- if (r < 0)
- io->error = -EIO;
-
- crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
-
- /* Encryption was already finished, submit io now */
- if (crypt_finished) {
- kcryptd_crypt_write_io_submit(io, 0);
-
- /*
- * If there was an error, do not try next fragments.
- * For async, error is processed in async handler.
- */
- if (unlikely(r < 0))
- break;
+ clone = crypt_alloc_buffer(io, io->base_bio->bi_iter.bi_size);
+ if (unlikely(!clone)) {
+ io->error = -EIO;
+ goto dec;
+ }
- io->sector = sector;
- }
+ io->ctx.bio_out = clone;
+ io->ctx.iter_out = clone->bi_iter;
- /*
- * Out of memory -> run queues
- * But don't wait if split was due to the io size restriction
- */
- if (unlikely(out_of_pages))
- congestion_wait(BLK_RW_ASYNC, HZ/100);
+ sector += bio_sectors(clone);
- /*
- * With async crypto it is unsafe to share the crypto context
- * between fragments, so switch to a new dm_crypt_io structure.
- */
- if (unlikely(!crypt_finished && remaining)) {
- new_io = mempool_alloc(cc->io_pool, GFP_NOIO);
- crypt_io_init(new_io, io->cc, io->base_bio, sector);
- crypt_inc_pending(new_io);
- crypt_convert_init(cc, &new_io->ctx, NULL,
- io->base_bio, sector);
- new_io->ctx.iter_in = io->ctx.iter_in;
-
- /*
- * Fragments after the first use the base_io
- * pending count.
- */
- if (!io->base_io)
- new_io->base_io = io;
- else {
- new_io->base_io = io->base_io;
- crypt_inc_pending(io->base_io);
- crypt_dec_pending(io);
- }
+ crypt_inc_pending(io);
+ r = crypt_convert(cc, &io->ctx);
+ if (r)
+ io->error = -EIO;
+ crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
- io = new_io;
- }
+ /* Encryption was already finished, submit io now */
+ if (crypt_finished) {
+ kcryptd_crypt_write_io_submit(io, 0);
+ io->sector = sector;
}
+dec:
crypt_dec_pending(io);
}
@@ -1738,7 +1659,7 @@ static int crypt_ctr(struct dm_target *t
sizeof(struct dm_crypt_io) + cc->dmreq_start +
sizeof(struct dm_crypt_request) + cc->iv_size;
- cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
+ cc->page_pool = mempool_create_page_pool(BIO_MAX_PAGES, 0);
if (!cc->page_pool) {
ti->error = "Cannot allocate page mempool";
goto bad;
--
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