From: Sarthak Kukreti <sarthakkukr...@chromium.org>

Add support to dm devices for REQ_OP_PROVISION. The default mode
is to pass through the request and dm-thin will utilize it to provision
blocks.

Signed-off-by: Sarthak Kukreti <sarthakkukr...@chromium.org>
---
 drivers/md/dm-crypt.c         |  4 +-
 drivers/md/dm-linear.c        |  1 +
 drivers/md/dm-table.c         | 17 +++++++
 drivers/md/dm-thin.c          | 86 +++++++++++++++++++++++++++++++++--
 drivers/md/dm.c               |  4 ++
 include/linux/device-mapper.h |  6 +++
 6 files changed, 113 insertions(+), 5 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 159c6806c19b..357f0899cfb6 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -3081,6 +3081,8 @@ static int crypt_ctr_optional(struct dm_target *ti, 
unsigned int argc, char **ar
        if (ret)
                return ret;
 
+       ti->num_provision_bios = 1;
+
        while (opt_params--) {
                opt_string = dm_shift_arg(&as);
                if (!opt_string) {
@@ -3384,7 +3386,7 @@ static int crypt_map(struct dm_target *ti, struct bio 
*bio)
         * - for REQ_OP_DISCARD caller must use flush if IO ordering matters
         */
        if (unlikely(bio->bi_opf & REQ_PREFLUSH ||
-           bio_op(bio) == REQ_OP_DISCARD)) {
+           bio_op(bio) == REQ_OP_DISCARD || bio_op(bio) == REQ_OP_PROVISION)) {
                bio_set_dev(bio, cc->dev->bdev);
                if (bio_sectors(bio))
                        bio->bi_iter.bi_sector = cc->start +
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 3212ef6aa81b..1aa782149428 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -61,6 +61,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int 
argc, char **argv)
        ti->num_discard_bios = 1;
        ti->num_secure_erase_bios = 1;
        ti->num_write_zeroes_bios = 1;
+       ti->num_provision_bios = 1;
        ti->private = lc;
        return 0;
 
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 332f96b58252..b7f9cb66b7ba 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1853,6 +1853,18 @@ static bool dm_table_supports_write_zeroes(struct 
dm_table *t)
        return true;
 }
 
+static bool dm_table_supports_provision(struct dm_table *t)
+{
+       for (unsigned int i = 0; i < t->num_targets; i++) {
+               struct dm_target *ti = dm_table_get_target(t, i);
+
+               if (ti->num_provision_bios)
+                       return true;
+       }
+
+       return false;
+}
+
 static int device_not_nowait_capable(struct dm_target *ti, struct dm_dev *dev,
                                     sector_t start, sector_t len, void *data)
 {
@@ -1989,6 +2001,11 @@ int dm_table_set_restrictions(struct dm_table *t, struct 
request_queue *q,
        if (!dm_table_supports_write_zeroes(t))
                q->limits.max_write_zeroes_sectors = 0;
 
+       if (dm_table_supports_provision(t))
+               blk_queue_max_provision_sectors(q, UINT_MAX >> 9);
+       else
+               q->limits.max_provision_sectors = 0;
+
        dm_table_verify_integrity(t);
 
        /*
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index e76c96c760a9..fd3eb306c823 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -908,7 +908,8 @@ static void __inc_remap_and_issue_cell(void *context,
        struct bio *bio;
 
        while ((bio = bio_list_pop(&cell->bios))) {
-               if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD)
+               if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD ||
+                   bio_op(bio) == REQ_OP_PROVISION)
                        bio_list_add(&info->defer_bios, bio);
                else {
                        inc_all_io_entry(info->tc->pool, bio);
@@ -1012,6 +1013,9 @@ static void process_prepared_mapping(struct 
dm_thin_new_mapping *m)
                goto out;
        }
 
+       if (bio && bio_op(bio) == REQ_OP_PROVISION)
+               return;
+
        /*
         * Release any bios held while the block was being provisioned.
         * If we are processing a write bio that completely covers the block,
@@ -1388,6 +1392,9 @@ static void schedule_zero(struct thin_c *tc, dm_block_t 
virt_block,
        m->data_block = data_block;
        m->cell = cell;
 
+       if (bio && bio_op(bio) == REQ_OP_PROVISION)
+               m->bio = bio;
+
        /*
         * If the whole block of data is being overwritten or we are not
         * zeroing pre-existing data, we can issue the bio immediately.
@@ -1897,7 +1904,7 @@ static void provision_block(struct thin_c *tc, struct bio 
*bio, dm_block_t block
        /*
         * Fill read bios with zeroes and complete them immediately.
         */
-       if (bio_data_dir(bio) == READ) {
+       if (bio_data_dir(bio) == READ && bio_op(bio) != REQ_OP_PROVISION) {
                zero_fill_bio(bio);
                cell_defer_no_holder(tc, cell);
                bio_endio(bio);
@@ -1980,6 +1987,69 @@ static void process_cell(struct thin_c *tc, struct 
dm_bio_prison_cell *cell)
        }
 }
 
+static void process_provision_cell(struct thin_c *tc, struct 
dm_bio_prison_cell *cell)
+{
+       int r;
+       struct pool *pool = tc->pool;
+       struct bio *bio = cell->holder;
+       dm_block_t begin, end;
+       struct dm_thin_lookup_result lookup_result;
+
+       if (tc->requeue_mode) {
+               cell_requeue(pool, cell);
+               return;
+       }
+
+       get_bio_block_range(tc, bio, &begin, &end);
+
+       while (begin != end) {
+               r = ensure_next_mapping(pool);
+               if (r)
+                       /* we did our best */
+                       return;
+
+               r = dm_thin_find_block(tc->td, begin, 1, &lookup_result);
+               switch (r) {
+               case 0:
+                       begin++;
+                       break;
+               case -ENODATA:
+                       provision_block(tc, bio, begin, cell);
+                       begin++;
+                       break;
+               default:
+                       DMERR_LIMIT(
+                               "%s: dm_thin_find_block() failed: error = %d",
+                               __func__, r);
+                       cell_defer_no_holder(tc, cell);
+                       bio_io_error(bio);
+                       begin++;
+                       break;
+               }
+       }
+       bio_endio(bio);
+       cell_defer_no_holder(tc, cell);
+}
+
+static void process_provision_bio(struct thin_c *tc, struct bio *bio)
+{
+       dm_block_t begin, end;
+       struct dm_cell_key virt_key;
+       struct dm_bio_prison_cell *virt_cell;
+
+       get_bio_block_range(tc, bio, &begin, &end);
+       if (begin == end) {
+               bio_endio(bio);
+               return;
+       }
+
+       build_key(tc->td, VIRTUAL, begin, end, &virt_key);
+       if (bio_detain(tc->pool, &virt_key, bio, &virt_cell))
+               return;
+
+       process_provision_cell(tc, virt_cell);
+}
+
 static void process_bio(struct thin_c *tc, struct bio *bio)
 {
        struct pool *pool = tc->pool;
@@ -2024,7 +2094,7 @@ static void __process_bio_read_only(struct thin_c *tc, 
struct bio *bio,
        case -ENODATA:
                if (cell)
                        cell_defer_no_holder(tc, cell);
-               if (rw != READ) {
+               if (rw != READ || bio_op(bio) == REQ_OP_PROVISION) {
                        handle_unserviceable_bio(tc->pool, bio);
                        break;
                }
@@ -2200,6 +2270,8 @@ static void process_thin_deferred_bios(struct thin_c *tc)
 
                if (bio_op(bio) == REQ_OP_DISCARD)
                        pool->process_discard(tc, bio);
+               else if (bio_op(bio) == REQ_OP_PROVISION)
+                       process_provision_bio(tc, bio);
                else
                        pool->process_bio(tc, bio);
 
@@ -2716,7 +2788,8 @@ static int thin_bio_map(struct dm_target *ti, struct bio 
*bio)
                return DM_MAPIO_SUBMITTED;
        }
 
-       if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) {
+       if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD ||
+           bio_op(bio) == REQ_OP_PROVISION) {
                thin_defer_bio_with_throttle(tc, bio);
                return DM_MAPIO_SUBMITTED;
        }
@@ -3353,6 +3426,7 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, 
char **argv)
        pt->low_water_blocks = low_water_blocks;
        pt->adjusted_pf = pt->requested_pf = pf;
        ti->num_flush_bios = 1;
+       ti->num_provision_bios = 1;
 
        /*
         * Only need to enable discards if the pool should pass
@@ -4043,6 +4117,7 @@ static void pool_io_hints(struct dm_target *ti, struct 
queue_limits *limits)
                blk_limits_io_opt(limits, pool->sectors_per_block << 
SECTOR_SHIFT);
        }
 
+
        /*
         * pt->adjusted_pf is a staging area for the actual features to use.
         * They get transferred to the live pool in bind_control_target()
@@ -4233,6 +4308,8 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, 
char **argv)
                ti->num_discard_bios = 1;
        }
 
+       ti->num_provision_bios = 1;
+
        mutex_unlock(&dm_thin_pool_table.mutex);
 
        spin_lock_irq(&tc->pool->lock);
@@ -4447,6 +4524,7 @@ static void thin_io_hints(struct dm_target *ti, struct 
queue_limits *limits)
 
        limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
        limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */
+       limits->max_provision_sectors = 2048 * 1024 * 16; /* 16G */
 }
 
 static struct target_type thin_target = {
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 60549b65c799..3fe524800f5a 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1600,6 +1600,7 @@ static bool is_abnormal_io(struct bio *bio)
                case REQ_OP_DISCARD:
                case REQ_OP_SECURE_ERASE:
                case REQ_OP_WRITE_ZEROES:
+               case REQ_OP_PROVISION:
                        return true;
                default:
                        break;
@@ -1624,6 +1625,9 @@ static blk_status_t __process_abnormal_io(struct 
clone_info *ci,
        case REQ_OP_WRITE_ZEROES:
                num_bios = ti->num_write_zeroes_bios;
                break;
+       case REQ_OP_PROVISION:
+               num_bios = ti->num_provision_bios;
+               break;
        default:
                break;
        }
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 04c6acf7faaa..edeb47195b6f 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -333,6 +333,12 @@ struct dm_target {
         */
        unsigned num_write_zeroes_bios;
 
+       /*
+        * The number of PROVISION bios that will be submitted to the target.
+        * The bio number can be accessed with dm_bio_get_target_bio_nr.
+        */
+       unsigned num_provision_bios;
+
        /*
         * The minimum number of extra bytes allocated in each io for the
         * target to use.
-- 
2.31.0

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