FAILED: patch "[PATCH] mm/cma: drop incorrect alignment check in" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x b174f139bdc8aaaf72f5b67ad1bd512c4868a87e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024061301-runt-mannish-7604@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

b174f139bdc8 ("mm/cma: drop incorrect alignment check in cma_init_reserved_mem")
e16faf26780f ("cma: factor out minimum alignment requirement")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b174f139bdc8aaaf72f5b67ad1bd512c4868a87e Mon Sep 17 00:00:00 2001
From: Frank van der Linden <fvdl@google.com>
Date: Thu, 4 Apr 2024 16:25:14 +0000
Subject: [PATCH] mm/cma: drop incorrect alignment check in
 cma_init_reserved_mem

cma_init_reserved_mem uses IS_ALIGNED to check if the size represented by
one bit in the cma allocation bitmask is aligned with
CMA_MIN_ALIGNMENT_BYTES (pageblock size).

However, this is too strict, as this will fail if order_per_bit >
pageblock_order, which is a valid configuration.

We could check IS_ALIGNED both ways, but since both numbers are powers of
two, no check is needed at all.

Link: https://lkml.kernel.org/r/20240404162515.527802-1-fvdl@google.com
Fixes: de9e14eebf33 ("drivers: dma-contiguous: add initialization from device tree")
Signed-off-by: Frank van der Linden <fvdl@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/cma.c b/mm/cma.c
index 01f5a8f71ddf..3e9724716bad 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -182,10 +182,6 @@ int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 	if (!size || !memblock_is_region_reserved(base, size))
 		return -EINVAL;
 
-	/* alignment should be aligned with order_per_bit */
-	if (!IS_ALIGNED(CMA_MIN_ALIGNMENT_PAGES, 1 << order_per_bit))
-		return -EINVAL;
-
 	/* ensure minimal alignment required by mm core */
 	if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES))
 		return -EINVAL;