buffer: pass GFP flags to folio_alloc_buffers()

buffer: pass GFP flags to folio_alloc_buffers()

Patch series "Add and use bdev_getblk()", v2.

This patch series fixes a bug reported by Hui Zhu; see proposed
patches v1 and v2:
https://lore.kernel.org/linux-fsdevel/20230811035705.3296-1-teawaterz@linux.alibaba.com/
https://lore.kernel.org/linux-fsdevel/20230811071519.1094-1-teawaterz@linux.alibaba.com/

I decided to go in a rather different direction for this fix, and fix a
related problem at the same time.  I don't think there's any urgency to
rush this into Linus' tree, nor have I marked it for stable.  Reasonable
people may disagree.

This patch (of 8):

Instead of creating entirely new flags, inherit them from grow_dev_page().
The other callers create the same flags that this function used to
create.

Link: https://lkml.kernel.org/r/20230914150011.843330-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230914150011.843330-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Hui Zhu <teawater@antgroup.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>