[RFC v2 1/4] cma: Enforce non-zero pageblock_order during cma_init_reserved_mem()
From: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Date: 2024-10-11 07:23:31
Also in:
linux-mm, lkml
Subsystem:
memory management, memory management - misc, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
cma_init_reserved_mem() checks base and size alignment with CMA_MIN_ALIGNMENT_BYTES. However, some users might call this during early boot when pageblock_order is 0. That means if base and size does not have pageblock_order alignment, it can cause functional failures during cma activate area. So let's enforce pageblock_order to be non-zero during cma_init_reserved_mem(). Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> --- mm/cma.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/mm/cma.c b/mm/cma.c
index 3e9724716bad..36d753e7a0bf 100644
--- a/mm/cma.c
+++ b/mm/cma.c@@ -182,6 +182,15 @@ int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size, if (!size || !memblock_is_region_reserved(base, size)) return -EINVAL; + /* + * CMA uses CMA_MIN_ALIGNMENT_BYTES as alignment requirement which + * needs pageblock_order to be initialized. Let's enforce it. + */ + if (!pageblock_order) { + pr_err("pageblock_order not yet initialized. Called during early boot?\n"); + return -EINVAL; + } + /* ensure minimal alignment required by mm core */ if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES)) return -EINVAL;
--
2.46.0