Re: [PATCH v20 1/5] arm64: Use insert_resource() to simplify code

[john . p . donnelly]

On 1/24/22 2:47 AM, Zhen Lei wrote:

insert_resource() traverses the subtree layer by layer from the root node
until a proper location is found. Compared with request_resource(), the
parent node does not need to be determined in advance.

In addition, move the insertion of node 'crashk_res' into function
reserve_crashkernel() to make the associated code close together.

Signed-off-by: Zhen Lei <thunder.leiz...@huawei.com>

Acked-by: John Donnelly  <john.p.donne...@oracle.com>

---
  arch/arm64/kernel/setup.c | 17 +++--------------
  arch/arm64/mm/init.c      |  1 +
  2 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index f70573928f1bff0..a81efcc359e4e78 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -225,6 +225,8 @@ static void __init request_standard_resources(void)
        kernel_code.end     = __pa_symbol(__init_begin - 1);
        kernel_data.start   = __pa_symbol(_sdata);
        kernel_data.end     = __pa_symbol(_end - 1);
+       insert_resource(&iomem_resource, &kernel_code);
+       insert_resource(&iomem_resource, &kernel_data);

num_standard_resources = memblock.memory.cnt;

        res_size = num_standard_resources * sizeof(*standard_resources);
@@ -246,20 +248,7 @@ static void __init request_standard_resources(void)
                        res->end = 
__pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
                }

- request_resource(&iomem_resource, res);

-
-               if (kernel_code.start >= res->start &&
-                   kernel_code.end <= res->end)
-                       request_resource(res, &kernel_code);
-               if (kernel_data.start >= res->start &&
-                   kernel_data.end <= res->end)
-                       request_resource(res, &kernel_data);
-#ifdef CONFIG_KEXEC_CORE
-               /* Userspace will find "Crash kernel" region in /proc/iomem. */
-               if (crashk_res.end && crashk_res.start >= res->start &&
-                   crashk_res.end <= res->end)
-                       request_resource(res, &crashk_res);
-#endif
+               insert_resource(&iomem_resource, res);
        }
  }

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c

index db63cc885771a52..90f276d46b93bc6 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -109,6 +109,7 @@ static void __init reserve_crashkernel(void)
        kmemleak_ignore_phys(crash_base);
        crashk_res.start = crash_base;
        crashk_res.end = crash_base + crash_size - 1;
+       insert_resource(&iomem_resource, &crashk_res);
  }
  #else
  static void __init reserve_crashkernel(void)

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