md/md-llbitmap: use GFP_NOIO for cache allocations

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llbitmap allocates its in-memory page cache and page-control structures from
paths that can already be holding MD reconfiguration or bitmap state locks.
For example, component_size_store() takes mddev_lock(), update_size() calls
the personality resize method, and llbitmap_resize() can grow the page cache
through llbitmap_prepare_resize().

Using GFP_KERNEL in those paths allows direct reclaim to enter filesystem or
block I/O while MD resize state is locked. That can recurse back into the
same array and wait on state that cannot make progress until the resize path
finishes.

Use GFP_NOIO for the llbitmap object, cached bitmap pages, page controls,
page-control arrays, and percpu_ref initialization. Leave the explicit
metadata zeroout path unchanged because it is intentional bitmap I/O rather
than reclaim-driven allocation.

Tested-by: Mykola Marzhan <mykola@meshstor.io>
Link: https://patch.msgid.link/20260802195038.164272-3-yukuai@kernel.org
Signed-off-by: Yu Kuai <yukuai@fygo.io>

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This commit is contained in:

Yu Kuai 2026-08-03 03:50:11 +08:00

parent 2f6b2073ea

commit 4b6cdc56c8

1 changed files with 5 additions and 5 deletions

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drivers/md/md-llbitmap.c

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