6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mikulas Patocka mpatocka@redhat.com
commit 42964e4b5e3ac95090bdd23ed7da2a941ccd902c upstream.
The commit 4c39529663b9 adds a warning about duplicate cache names if CONFIG_DEBUG_VM is selected. These warnings are triggered by the dm-bufio code. The dm-bufio code allocates a slab cache with each client. It is not possible to preallocate the caches in the module init function because the size of auxiliary per-buffer data is not known at this point.
So, this commit changes dm-bufio so that it appends a unique atomic value to the cache name, to avoid the warnings.
Signed-off-by: Mikulas Patocka mpatocka@redhat.com Fixes: 4c39529663b9 ("slab: Warn on duplicate cache names when DEBUG_VM=y") Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/dm-bufio.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
--- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -2444,7 +2444,8 @@ struct dm_bufio_client *dm_bufio_client_ int r; unsigned int num_locks; struct dm_bufio_client *c; - char slab_name[27]; + char slab_name[64]; + static atomic_t seqno = ATOMIC_INIT(0);
if (!block_size || block_size & ((1 << SECTOR_SHIFT) - 1)) { DMERR("%s: block size not specified or is not multiple of 512b", __func__); @@ -2495,7 +2496,8 @@ struct dm_bufio_client *dm_bufio_client_ (block_size < PAGE_SIZE || !is_power_of_2(block_size))) { unsigned int align = min(1U << __ffs(block_size), (unsigned int)PAGE_SIZE);
- snprintf(slab_name, sizeof(slab_name), "dm_bufio_cache-%u", block_size); + snprintf(slab_name, sizeof(slab_name), "dm_bufio_cache-%u-%u", + block_size, atomic_inc_return(&seqno)); c->slab_cache = kmem_cache_create(slab_name, block_size, align, SLAB_RECLAIM_ACCOUNT, NULL); if (!c->slab_cache) { @@ -2504,9 +2506,11 @@ struct dm_bufio_client *dm_bufio_client_ } } if (aux_size) - snprintf(slab_name, sizeof(slab_name), "dm_bufio_buffer-%u", aux_size); + snprintf(slab_name, sizeof(slab_name), "dm_bufio_buffer-%u-%u", + aux_size, atomic_inc_return(&seqno)); else - snprintf(slab_name, sizeof(slab_name), "dm_bufio_buffer"); + snprintf(slab_name, sizeof(slab_name), "dm_bufio_buffer-%u", + atomic_inc_return(&seqno)); c->slab_buffer = kmem_cache_create(slab_name, sizeof(struct dm_buffer) + aux_size, 0, SLAB_RECLAIM_ACCOUNT, NULL); if (!c->slab_buffer) {