mm/vmalloc: check free space in vmap_block lockless

vb_alloc() unconditionally locks a vmap_block on the free list to check
the free space.

This can be done locklessly because vmap_block::free never increases, it's
only decreased on allocations.

Check the free space lockless and only if that succeeds, recheck under the
lock.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Uladzislau Rezki (Sony) <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Baoquan He <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions