+++ /dev/null
-dm-crypt: remove per-cpu structure
-
-Dm-crypt used per-cpu structures to hold pointers to ablkcipher_request.
-The code assumed that the work item keeps executing on a single CPU, so it
-used no synchronization when accessing this structure.
-
-When we disable a CPU by writing zero to
-/sys/devices/system/cpu/cpu*/online, the work item could be moved to
-another CPU. This causes crashes in dm-crypt because the code starts using
-a wrong ablkcipher_request.
-
-This patch fixes this bug by removing the percpu definition. The structure
-ablkcipher_request is accessed via a pointer from convert_context.
-Consequently, if the work item is rescheduled to a different CPU, the
-thread still uses the same ablkcipher_request.
-
-Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
-Cc: stable@vger.kernel.org
-
----
- drivers/md/dm-crypt.c | 61 +++++++++-----------------------------------------
- 1 file changed, 12 insertions(+), 49 deletions(-)
-
-Index: linux-3.14-rc1/drivers/md/dm-crypt.c
-===================================================================
---- linux-3.14-rc1.orig/drivers/md/dm-crypt.c 2014-02-03 19:18:23.000000000 +0100
-+++ linux-3.14-rc1/drivers/md/dm-crypt.c 2014-02-03 19:21:35.000000000 +0100
-@@ -19,7 +19,6 @@
- #include <linux/crypto.h>
- #include <linux/workqueue.h>
- #include <linux/backing-dev.h>
--#include <linux/percpu.h>
- #include <linux/atomic.h>
- #include <linux/scatterlist.h>
- #include <asm/page.h>
-@@ -43,6 +42,7 @@ struct convert_context {
- struct bvec_iter iter_out;
- sector_t cc_sector;
- atomic_t cc_pending;
-+ struct ablkcipher_request *req;
- };
-
- /*
-@@ -111,15 +111,7 @@ struct iv_tcw_private {
- enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
-
- /*
-- * Duplicated per-CPU state for cipher.
-- */
--struct crypt_cpu {
-- struct ablkcipher_request *req;
--};
--
--/*
-- * The fields in here must be read only after initialization,
-- * changing state should be in crypt_cpu.
-+ * The fields in here must be read only after initialization.
- */
- struct crypt_config {
- struct dm_dev *dev;
-@@ -150,12 +142,6 @@ struct crypt_config {
- sector_t iv_offset;
- unsigned int iv_size;
-
-- /*
-- * Duplicated per cpu state. Access through
-- * per_cpu_ptr() only.
-- */
-- struct crypt_cpu __percpu *cpu;
--
- /* ESSIV: struct crypto_cipher *essiv_tfm */
- void *iv_private;
- struct crypto_ablkcipher **tfms;
-@@ -192,11 +178,6 @@ static void clone_init(struct dm_crypt_i
- static void kcryptd_queue_crypt(struct dm_crypt_io *io);
- static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
-
--static struct crypt_cpu *this_crypt_config(struct crypt_config *cc)
--{
-- return this_cpu_ptr(cc->cpu);
--}
--
- /*
- * Use this to access cipher attributes that are the same for each CPU.
- */
-@@ -903,16 +884,15 @@ static void kcryptd_async_done(struct cr
- static void crypt_alloc_req(struct crypt_config *cc,
- struct convert_context *ctx)
- {
-- struct crypt_cpu *this_cc = this_crypt_config(cc);
- unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
-
-- if (!this_cc->req)
-- this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
-+ if (!ctx->req)
-+ ctx->req = mempool_alloc(cc->req_pool, GFP_NOIO);
-
-- ablkcipher_request_set_tfm(this_cc->req, cc->tfms[key_index]);
-- ablkcipher_request_set_callback(this_cc->req,
-+ ablkcipher_request_set_tfm(ctx->req, cc->tfms[key_index]);
-+ ablkcipher_request_set_callback(ctx->req,
- CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-- kcryptd_async_done, dmreq_of_req(cc, this_cc->req));
-+ kcryptd_async_done, dmreq_of_req(cc, ctx->req));
- }
-
- /*
-@@ -921,7 +901,6 @@ static void crypt_alloc_req(struct crypt
- static int crypt_convert(struct crypt_config *cc,
- struct convert_context *ctx)
- {
-- struct crypt_cpu *this_cc = this_crypt_config(cc);
- int r;
-
- atomic_set(&ctx->cc_pending, 1);
-@@ -932,7 +911,7 @@ static int crypt_convert(struct crypt_co
-
- atomic_inc(&ctx->cc_pending);
-
-- r = crypt_convert_block(cc, ctx, this_cc->req);
-+ r = crypt_convert_block(cc, ctx, ctx->req);
-
- switch (r) {
- /* async */
-@@ -941,7 +920,7 @@ static int crypt_convert(struct crypt_co
- reinit_completion(&ctx->restart);
- /* fall through*/
- case -EINPROGRESS:
-- this_cc->req = NULL;
-+ ctx->req = NULL;
- ctx->cc_sector++;
- continue;
-
-@@ -1040,6 +1019,7 @@ static struct dm_crypt_io *crypt_io_allo
- io->sector = sector;
- io->error = 0;
- io->base_io = NULL;
-+ io->ctx.req = NULL;
- atomic_set(&io->io_pending, 0);
-
- return io;
-@@ -1065,6 +1045,8 @@ static void crypt_dec_pending(struct dm_
- if (!atomic_dec_and_test(&io->io_pending))
- return;
-
-+ if (io->ctx.req)
-+ mempool_free(io->ctx.req, cc->req_pool);
- mempool_free(io, cc->io_pool);
-
- if (likely(!base_io))
-@@ -1492,8 +1474,6 @@ static int crypt_wipe_key(struct crypt_c
- static void crypt_dtr(struct dm_target *ti)
- {
- struct crypt_config *cc = ti->private;
-- struct crypt_cpu *cpu_cc;
-- int cpu;
-
- ti->private = NULL;
-
-@@ -1505,13 +1485,6 @@ static void crypt_dtr(struct dm_target *
- if (cc->crypt_queue)
- destroy_workqueue(cc->crypt_queue);
-
-- if (cc->cpu)
-- for_each_possible_cpu(cpu) {
-- cpu_cc = per_cpu_ptr(cc->cpu, cpu);
-- if (cpu_cc->req)
-- mempool_free(cpu_cc->req, cc->req_pool);
-- }
--
- crypt_free_tfms(cc);
-
- if (cc->bs)
-@@ -1530,9 +1503,6 @@ static void crypt_dtr(struct dm_target *
- if (cc->dev)
- dm_put_device(ti, cc->dev);
-
-- if (cc->cpu)
-- free_percpu(cc->cpu);
--
- kzfree(cc->cipher);
- kzfree(cc->cipher_string);
-
-@@ -1588,13 +1558,6 @@ static int crypt_ctr_cipher(struct dm_ta
- if (tmp)
- DMWARN("Ignoring unexpected additional cipher options");
-
-- cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)),
-- __alignof__(struct crypt_cpu));
-- if (!cc->cpu) {
-- ti->error = "Cannot allocate per cpu state";
-- goto bad_mem;
-- }
--
- /*
- * For compatibility with the original dm-crypt mapping format, if
- * only the cipher name is supplied, use cbc-plain.
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