x86: Change crash kernel to reserve via reserve_early()

use find_e820_area()/reserve_early() instead.

-v2: address Eric's request, to restore original semantics.
     will fail, if the provided address can not be used.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <4B09E2F9.7040403@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 15 insertions, 42 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index d2043a00abc1..e3eae5965e4a 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -487,42 +487,11 @@ static void __init reserve_early_setup_data(void)
 
 #ifdef CONFIG_KEXEC
 
-/**
- * Reserve @size bytes of crashkernel memory at any suitable offset.
- *
- * @size: Size of the crashkernel memory to reserve.
- * Returns the base address on success, and -1ULL on failure.
- */
-static
-unsigned long long __init find_and_reserve_crashkernel(unsigned long long size)
-{
-        const unsigned long long alignment = 16<<20;    /* 16M */
-        unsigned long long start = 0LL;
-
-        while (1) {
-                int ret;
-
-                start = find_e820_area(start, ULONG_MAX, size, alignment);
-                if (start == -1ULL)
-                        return start;
-
-                /* try to reserve it */
-                ret = reserve_bootmem_generic(start, size, BOOTMEM_EXCLUSIVE);
-                if (ret >= 0)
-                        return start;
-
-                start += alignment;
-        }
-}
-
 static inline unsigned long long get_total_mem(void)
 {
         unsigned long long total;
 
-        total = max_low_pfn - min_low_pfn;
-#ifdef CONFIG_HIGHMEM
-        total += highend_pfn - highstart_pfn;
-#endif
+        total = max_pfn - min_low_pfn;
 
         return total << PAGE_SHIFT;
 }
@@ -542,21 +511,25 @@ static void __init reserve_crashkernel(void)
 
         /* 0 means: find the address automatically */
         if (crash_base <= 0) {
-                crash_base = find_and_reserve_crashkernel(crash_size);
+                const unsigned long long alignment = 16<<20;    /* 16M */
+
+                crash_base = find_e820_area(alignment, ULONG_MAX, crash_size,
+                                 alignment);
                 if (crash_base == -1ULL) {
-                        pr_info("crashkernel reservation failed. "
-                                "No suitable area found.\n");
+                        pr_info("crashkernel reservation failed - No suitable area found.\n");
                         return;
                 }
         } else {
-                ret = reserve_bootmem_generic(crash_base, crash_size,
-                                        BOOTMEM_EXCLUSIVE);
-                if (ret < 0) {
-                        pr_info("crashkernel reservation failed - "
-                                "memory is in use\n");
+                unsigned long long start;
+
+                start = find_e820_area(crash_base, ULONG_MAX, crash_size,
+                                 1<<20);
+                if (start != crash_base) {
+                        pr_info("crashkernel reservation failed - memory is in use.\n");
                         return;
                 }
         }
+        reserve_early(crash_base, crash_base + crash_size, "CRASH KERNEL");
 
         printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
                         "for crashkernel (System RAM: %ldMB)\n",
@@ -927,6 +900,8 @@ void __init setup_arch(char **cmdline_p)
 
         reserve_initrd();
 
+        reserve_crashkernel();
+
         vsmp_init();
 
         io_delay_init();
@@ -957,8 +932,6 @@ void __init setup_arch(char **cmdline_p)
          */
         find_smp_config();
 
-        reserve_crashkernel();
-
 #ifdef CONFIG_X86_64
         /*
          * dma32_reserve_bootmem() allocates bootmem which may conflict