Merge branch 'slab/for-6.19/mempool_alloc_bulk' into slab/for-next

Merges series "mempool_alloc_bulk and various mempool improvements v3"
from Christoph Hellwig.

From the cover letter [1]:

This series adds a bulk version of mempool_alloc that makes allocating
multiple objects deadlock safe.

The initial users is the blk-crypto-fallback code:

  https://lore.kernel.org/linux-block/20251031093517.1603379-1-hch@lst.de/

with which v1 was posted, but I also have a few other users in mind.

Link: https://lore.kernel.org/all/20251113084022.1255121-1-hch@lst.de/