[PATCH 1/2] dm: introduce the target flag mempool_needs_integrity

[Mikulas Patocka]

This commit introduces the dm target flag mempool_needs_integrity. When
the flag is set, device mapper will call bioset_integrity_create on it's
bio sets. The target can then call bio_integrity_alloc on the bios
allocated from the table's mempool.

Signed-off-by: Mikulas Patocka <mpato...@redhat.com>

---
 drivers/md/dm-table.c         |    7 +++++--
 include/linux/device-mapper.h |    6 ++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

Index: linux-2.6/include/linux/device-mapper.h
===================================================================
--- linux-2.6.orig/include/linux/device-mapper.h        2024-06-25 
19:25:12.000000000 +0200
+++ linux-2.6/include/linux/device-mapper.h     2024-06-25 19:25:30.000000000 
+0200
@@ -397,6 +397,12 @@ struct dm_target {
         * bio_set_dev(). NOTE: ideally a target should _not_ need this.
         */
        bool needs_bio_set_dev:1;
+
+       /*
+        * Set if the target calls bio_integrity_alloc on bios received
+        * in the map method.
+        */
+       bool mempool_needs_integrity:1;
 };
 
 void *dm_per_bio_data(struct bio *bio, size_t data_size);
Index: linux-2.6/drivers/md/dm-table.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-table.c        2024-06-25 19:25:15.000000000 
+0200
+++ linux-2.6/drivers/md/dm-table.c     2024-06-25 19:25:44.000000000 +0200
@@ -1022,6 +1022,7 @@ static int dm_table_alloc_md_mempools(st
        unsigned int per_io_data_size = 0, front_pad, io_front_pad;
        unsigned int min_pool_size = 0, pool_size;
        struct dm_md_mempools *pools;
+       bool mempool_needs_integrity = t->integrity_supported;
 
        if (unlikely(type == DM_TYPE_NONE)) {
                DMERR("no table type is set, can't allocate mempools");
@@ -1043,6 +1044,8 @@ static int dm_table_alloc_md_mempools(st
 
                per_io_data_size = max(per_io_data_size, ti->per_io_data_size);
                min_pool_size = max(min_pool_size, ti->num_flush_bios);
+
+               mempool_needs_integrity |= ti->mempool_needs_integrity;
        }
        pool_size = max(dm_get_reserved_bio_based_ios(), min_pool_size);
        front_pad = roundup(per_io_data_size,
@@ -1053,13 +1056,13 @@ static int dm_table_alloc_md_mempools(st
        if (bioset_init(&pools->io_bs, pool_size, io_front_pad,
                        dm_table_supports_poll(t) ? BIOSET_PERCPU_CACHE : 0))
                goto out_free_pools;
-       if (t->integrity_supported &&
+       if (mempool_needs_integrity &&
            bioset_integrity_create(&pools->io_bs, pool_size))
                goto out_free_pools;
 init_bs:
        if (bioset_init(&pools->bs, pool_size, front_pad, 0))
                goto out_free_pools;
-       if (t->integrity_supported &&
+       if (mempool_needs_integrity &&
            bioset_integrity_create(&pools->bs, pool_size))
                goto out_free_pools;