mirror of
https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git
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Revert "block, dm: don't copy bios for request clones"
This reverts commit 5f1b670d0b.
Justification for revert as reported in this dm-devel post:
https://www.redhat.com/archives/dm-devel/2015-June/msg00160.html
this change should not be pushed to mainline yet.
Firstly, Christoph has a newer version of the patch that fixes silent
data corruption problem:
https://www.redhat.com/archives/dm-devel/2015-May/msg00229.html
And the new version still depends on LLDDs to always complete requests
to the end when error happens, while block API doesn't enforce such a
requirement. If the assumption is ever broken, the inconsistency between
request and bio (e.g. rq->__sector and rq->bio) will cause silent data
corruption:
https://www.redhat.com/archives/dm-devel/2015-June/msg00022.html
Reported-by: Junichi Nomura <[email protected]>
Signed-off-by: Mike Snitzer <[email protected]>
This commit is contained in:
Mike Snitzer
parent
4e6e36c371
commit
78d8e58a08
6 changed files with 230 additions and 73 deletions
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@ -942,28 +942,21 @@ static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *
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{
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unsigned type = dm_table_get_type(t);
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unsigned per_bio_data_size = 0;
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struct dm_target *tgt;
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unsigned i;
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switch (type) {
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case DM_TYPE_BIO_BASED:
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for (i = 0; i < t->num_targets; i++) {
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struct dm_target *tgt = t->targets + i;
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per_bio_data_size = max(per_bio_data_size,
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tgt->per_bio_data_size);
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}
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t->mempools = dm_alloc_bio_mempools(t->integrity_supported,
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per_bio_data_size);
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break;
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case DM_TYPE_REQUEST_BASED:
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case DM_TYPE_MQ_REQUEST_BASED:
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t->mempools = dm_alloc_rq_mempools(md, type);
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break;
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default:
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if (unlikely(type == DM_TYPE_NONE)) {
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DMWARN("no table type is set, can't allocate mempools");
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return -EINVAL;
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}
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if (type == DM_TYPE_BIO_BASED)
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for (i = 0; i < t->num_targets; i++) {
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tgt = t->targets + i;
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per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
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}
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t->mempools = dm_alloc_md_mempools(md, type, t->integrity_supported, per_bio_data_size);
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if (!t->mempools)
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return -ENOMEM;
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171
drivers/md/dm.c
171
drivers/md/dm.c
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@ -993,6 +993,57 @@ static void clone_endio(struct bio *bio, int error)
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dec_pending(io, error);
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}
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/*
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* Partial completion handling for request-based dm
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*/
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static void end_clone_bio(struct bio *clone, int error)
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{
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struct dm_rq_clone_bio_info *info =
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container_of(clone, struct dm_rq_clone_bio_info, clone);
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struct dm_rq_target_io *tio = info->tio;
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struct bio *bio = info->orig;
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unsigned int nr_bytes = info->orig->bi_iter.bi_size;
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bio_put(clone);
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if (tio->error)
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/*
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* An error has already been detected on the request.
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* Once error occurred, just let clone->end_io() handle
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* the remainder.
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*/
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return;
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else if (error) {
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/*
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* Don't notice the error to the upper layer yet.
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* The error handling decision is made by the target driver,
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* when the request is completed.
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*/
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tio->error = error;
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return;
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}
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/*
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* I/O for the bio successfully completed.
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* Notice the data completion to the upper layer.
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*/
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/*
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* bios are processed from the head of the list.
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* So the completing bio should always be rq->bio.
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* If it's not, something wrong is happening.
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*/
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if (tio->orig->bio != bio)
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DMERR("bio completion is going in the middle of the request");
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/*
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* Update the original request.
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* Do not use blk_end_request() here, because it may complete
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* the original request before the clone, and break the ordering.
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*/
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blk_update_request(tio->orig, 0, nr_bytes);
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}
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static struct dm_rq_target_io *tio_from_request(struct request *rq)
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{
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return (rq->q->mq_ops ? blk_mq_rq_to_pdu(rq) : rq->special);
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@ -1050,6 +1101,8 @@ static void free_rq_clone(struct request *clone)
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struct dm_rq_target_io *tio = clone->end_io_data;
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struct mapped_device *md = tio->md;
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blk_rq_unprep_clone(clone);
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if (md->type == DM_TYPE_MQ_REQUEST_BASED)
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/* stacked on blk-mq queue(s) */
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tio->ti->type->release_clone_rq(clone);
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@ -1784,13 +1837,39 @@ static void dm_dispatch_clone_request(struct request *clone, struct request *rq)
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dm_complete_request(rq, r);
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}
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static void setup_clone(struct request *clone, struct request *rq,
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struct dm_rq_target_io *tio)
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static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
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void *data)
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{
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blk_rq_prep_clone(clone, rq);
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struct dm_rq_target_io *tio = data;
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struct dm_rq_clone_bio_info *info =
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container_of(bio, struct dm_rq_clone_bio_info, clone);
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info->orig = bio_orig;
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info->tio = tio;
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bio->bi_end_io = end_clone_bio;
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return 0;
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}
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static int setup_clone(struct request *clone, struct request *rq,
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struct dm_rq_target_io *tio, gfp_t gfp_mask)
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{
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int r;
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r = blk_rq_prep_clone(clone, rq, tio->md->bs, gfp_mask,
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dm_rq_bio_constructor, tio);
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if (r)
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return r;
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clone->cmd = rq->cmd;
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clone->cmd_len = rq->cmd_len;
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clone->sense = rq->sense;
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clone->end_io = end_clone_request;
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clone->end_io_data = tio;
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tio->clone = clone;
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return 0;
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}
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static struct request *clone_rq(struct request *rq, struct mapped_device *md,
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@ -1811,7 +1890,12 @@ static struct request *clone_rq(struct request *rq, struct mapped_device *md,
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clone = tio->clone;
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blk_rq_init(NULL, clone);
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setup_clone(clone, rq, tio);
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if (setup_clone(clone, rq, tio, gfp_mask)) {
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/* -ENOMEM */
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if (alloc_clone)
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free_clone_request(md, clone);
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return NULL;
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}
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return clone;
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}
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@ -1905,7 +1989,11 @@ static int map_request(struct dm_rq_target_io *tio, struct request *rq,
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}
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if (r != DM_MAPIO_REMAPPED)
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return r;
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setup_clone(clone, rq, tio);
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if (setup_clone(clone, rq, tio, GFP_ATOMIC)) {
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/* -ENOMEM */
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ti->type->release_clone_rq(clone);
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return DM_MAPIO_REQUEUE;
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}
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}
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switch (r) {
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@ -2375,6 +2463,8 @@ static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
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goto out;
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}
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BUG_ON(!p || md->io_pool || md->rq_pool || md->bs);
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md->io_pool = p->io_pool;
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p->io_pool = NULL;
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md->rq_pool = p->rq_pool;
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@ -3481,23 +3571,48 @@ int dm_noflush_suspending(struct dm_target *ti)
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}
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EXPORT_SYMBOL_GPL(dm_noflush_suspending);
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struct dm_md_mempools *dm_alloc_bio_mempools(unsigned integrity,
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unsigned per_bio_data_size)
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struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned type,
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unsigned integrity, unsigned per_bio_data_size)
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{
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struct dm_md_mempools *pools;
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unsigned int pool_size = dm_get_reserved_bio_based_ios();
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struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL);
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struct kmem_cache *cachep = NULL;
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unsigned int pool_size = 0;
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unsigned int front_pad;
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pools = kzalloc(sizeof(*pools), GFP_KERNEL);
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if (!pools)
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return NULL;
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front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) +
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offsetof(struct dm_target_io, clone);
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type = filter_md_type(type, md);
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pools->io_pool = mempool_create_slab_pool(pool_size, _io_cache);
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if (!pools->io_pool)
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goto out;
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switch (type) {
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case DM_TYPE_BIO_BASED:
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cachep = _io_cache;
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pool_size = dm_get_reserved_bio_based_ios();
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front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
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break;
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case DM_TYPE_REQUEST_BASED:
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cachep = _rq_tio_cache;
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pool_size = dm_get_reserved_rq_based_ios();
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pools->rq_pool = mempool_create_slab_pool(pool_size, _rq_cache);
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if (!pools->rq_pool)
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goto out;
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/* fall through to setup remaining rq-based pools */
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case DM_TYPE_MQ_REQUEST_BASED:
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if (!pool_size)
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pool_size = dm_get_reserved_rq_based_ios();
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front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
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/* per_bio_data_size is not used. See __bind_mempools(). */
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WARN_ON(per_bio_data_size != 0);
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break;
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default:
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BUG();
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}
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if (cachep) {
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pools->io_pool = mempool_create_slab_pool(pool_size, cachep);
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if (!pools->io_pool)
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goto out;
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}
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pools->bs = bioset_create_nobvec(pool_size, front_pad);
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if (!pools->bs)
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@ -3507,34 +3622,10 @@ struct dm_md_mempools *dm_alloc_bio_mempools(unsigned integrity,
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goto out;
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return pools;
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out:
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dm_free_md_mempools(pools);
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return NULL;
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}
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struct dm_md_mempools *dm_alloc_rq_mempools(struct mapped_device *md,
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unsigned type)
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{
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unsigned int pool_size = dm_get_reserved_rq_based_ios();
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struct dm_md_mempools *pools;
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pools = kzalloc(sizeof(*pools), GFP_KERNEL);
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if (!pools)
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return NULL;
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if (filter_md_type(type, md) == DM_TYPE_REQUEST_BASED) {
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pools->rq_pool = mempool_create_slab_pool(pool_size, _rq_cache);
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if (!pools->rq_pool)
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goto out;
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}
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pools->io_pool = mempool_create_slab_pool(pool_size, _rq_tio_cache);
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if (!pools->io_pool)
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goto out;
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return pools;
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out:
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dm_free_md_mempools(pools);
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return NULL;
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}
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@ -222,9 +222,8 @@ void dm_kcopyd_exit(void);
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/*
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* Mempool operations
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*/
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struct dm_md_mempools *dm_alloc_bio_mempools(unsigned integrity,
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unsigned per_bio_data_size);
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struct dm_md_mempools *dm_alloc_rq_mempools(struct mapped_device *md, unsigned type);
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struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned type,
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unsigned integrity, unsigned per_bio_data_size);
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void dm_free_md_mempools(struct dm_md_mempools *pools);
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/*
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