[PATCH v2 3/3] arm64: kdump: Remove some redundant checks in map_mem()

[Zhen Lei]

arm64_memblock_init()
	if (!IS_ENABLED(CONFIG_ZONE_DMA/DMA32))
		reserve_crashkernel()
			//initialize crashk_res when
			//"crashkernel=" is correctly specified
paging_init()
	map_mem()

As shown in the above pseudo code, the crashk_res.end can only be
initialized to non-zero when both "!IS_ENABLED(CONFIG_ZONE_DMA/DMA32)"
and crash_mem_map are true. So some checks in map_mem() can be adjusted
or optimized.

Signed-off-by: Zhen Lei <thunder.leizhen at huawei.com>
Acked-by: Baoquan He <bhe at redhat.com>
---
 arch/arm64/mm/mmu.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 626ec32873c6c36..6028a5757e4eae2 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -529,12 +529,12 @@ static void __init map_mem(pgd_t *pgdp)
 
 #ifdef CONFIG_KEXEC_CORE
 	if (crash_mem_map) {
-		if (IS_ENABLED(CONFIG_ZONE_DMA) ||
-		    IS_ENABLED(CONFIG_ZONE_DMA32))
-			flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
-		else if (crashk_res.end)
+		if (crashk_res.end)
 			memblock_mark_nomap(crashk_res.start,
 			    resource_size(&crashk_res));
+		else if (IS_ENABLED(CONFIG_ZONE_DMA) ||
+			 IS_ENABLED(CONFIG_ZONE_DMA32))
+			flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 	}
 #endif
 
@@ -571,16 +571,13 @@ static void __init map_mem(pgd_t *pgdp)
 	 * through /sys/kernel/kexec_crash_size interface.
 	 */
 #ifdef CONFIG_KEXEC_CORE
-	if (crash_mem_map &&
-	    !IS_ENABLED(CONFIG_ZONE_DMA) && !IS_ENABLED(CONFIG_ZONE_DMA32)) {
-		if (crashk_res.end) {
-			__map_memblock(pgdp, crashk_res.start,
-				       crashk_res.end + 1,
-				       PAGE_KERNEL,
-				       NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
-			memblock_clear_nomap(crashk_res.start,
-					     resource_size(&crashk_res));
-		}
+	if (crashk_res.end) {
+		__map_memblock(pgdp, crashk_res.start,
+			       crashk_res.end + 1,
+			       PAGE_KERNEL,
+			       NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
+		memblock_clear_nomap(crashk_res.start,
+				     resource_size(&crashk_res));
 	}
 #endif
 }
-- 
2.25.1