From f875db4f20f4ec2e4fa3b3be0e5081976e0b5dad Mon Sep 17 00:00:00 2001 From: Zhenhua Huang Date: Thu, 7 Sep 2023 16:03:56 +0800 Subject: [PATCH] Revert "dma-contiguous: check for memory region overlap" MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This reverts commit 3fa6456ebe13adab3ba1817c8e515a5b88f95dce. The Commit broke the CMA region creation through DT on arm64, as showed below logs with "memblock=debug": [ 0.000000] memblock_phys_alloc_range: 41943040 bytes align=0x200000 from=0x0000000000000000 max_addr=0x00000000ffffffff early_init_dt_alloc_reserved_memory_arch+0x34/0xa0 [ 0.000000] memblock_reserve: [0x00000000fd600000-0x00000000ffdfffff] memblock_alloc_range_nid+0xc0/0x19c [ 0.000000] Reserved memory: overlap with other memblock reserved region >From call flow, region we defined in DT was always reserved before entering into rmem_cma_setup. Also, rmem_cma_setup has one routine cma_init_reserved_mem to ensure the region was reserved. Checking the region not reserved here seems not correct. early_init_fdt_scan_reserved_mem: fdt_scan_reserved_mem __reserved_mem_reserve_reg early_init_dt_reserve_memory memblock_reserve(using “reg” prop case) fdt_init_reserved_mem __reserved_mem_alloc_size *early_init_dt_alloc_reserved_memory_arch* memblock_reserve(dynamic alloc case) __reserved_mem_init_node rmem_cma_setup(region overlap check here should always fail) Example DT can be used to reproduce issue: dump_mem: mem_dump_region { compatible = "shared-dma-pool"; alloc-ranges = <0x0 0x00000000 0x0 0xffffffff>; reusable; size = <0 0x2800000>; }; Signed-off-by: Zhenhua Huang --- kernel/dma/contiguous.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c index 88c595e..f005c66 100644 --- a/kernel/dma/contiguous.c +++ b/kernel/dma/contiguous.c @@ -473,11 +473,6 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem) return -EBUSY; } - if (memblock_is_region_reserved(rmem->base, rmem->size)) { - pr_info("Reserved memory: overlap with other memblock reserved region\n"); - return -EBUSY; - } - if (!of_get_flat_dt_prop(node, "reusable", NULL) || of_get_flat_dt_prop(node, "no-map", NULL)) return -EINVAL; -- 2.7.4