[PATCH v14 13/17] LoongArch: kexec: Use crash_prepare_headers() helper to simplify code

[Jinjie Ruan]

Use the newly introduced crash_prepare_headers() function to replace
the existing prepare_elf_headers(), allocate cmem and exclude crash kernel
memory in the crash core, which reduce code duplication.

Only the following two architecture functions need to be implemented:
- arch_get_system_nr_ranges(). Use for_each_mem_range to traverse
  and pre-count the max number of memory ranges.

- arch_crash_populate_cmem(). Use for_each_mem_range to traverse
  and collect the memory ranges and fills them into cmem.

Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
Cc: WANG Xuerui <kernel@xxxxxxxxxx>
Cc: Youling Tang <tangyouling@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Reviewed-by: Sourabh Jain <sourabhjain@xxxxxxxxxxxxx>
Acked-by: Baoquan He <bhe@xxxxxxxxxx>
Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
 arch/loongarch/kernel/machine_kexec_file.c | 50 ++++++----------------
 1 file changed, 14 insertions(+), 36 deletions(-)

diff --git a/arch/loongarch/kernel/machine_kexec_file.c b/arch/loongarch/kernel/machine_kexec_file.c
index 2a1a6124f043..a845fbe8883d 100644
--- a/arch/loongarch/kernel/machine_kexec_file.c
+++ b/arch/loongarch/kernel/machine_kexec_file.c
@@ -14,7 +14,6 @@
 #include <linux/kernel.h>
 #include <linux/kexec.h>
 #include <linux/memblock.h>
-#include <linux/memory_hotplug.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/types.h>
@@ -57,51 +56,33 @@ static void cmdline_add_initrd(struct kimage *image, unsigned long *cmdline_tmpl
 }
 
 #ifdef CONFIG_CRASH_DUMP
-
-static int prepare_elf_headers(void **addr, unsigned long *sz)
+unsigned int arch_get_system_nr_ranges(void)
 {
-	int ret, nr_ranges;
-	uint64_t i;
+	int nr_ranges = 2; /* for exclusion of crashkernel region */
 	phys_addr_t start, end;
-	struct crash_mem *cmem;
+	uint64_t i;
 
-	nr_ranges = 2; /* for exclusion of crashkernel region */
 	for_each_mem_range(i, &start, &end)
 		nr_ranges++;
 
-	cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
-	if (!cmem)
-		return -ENOMEM;
+	return nr_ranges;
+}
+
+int arch_crash_populate_cmem(struct crash_mem *cmem)
+{
+	phys_addr_t start, end;
+	uint64_t i;
 
-	cmem->max_nr_ranges = nr_ranges;
-	cmem->nr_ranges = 0;
 	for_each_mem_range(i, &start, &end) {
-		if (WARN_ON_ONCE(cmem->nr_ranges >= cmem->max_nr_ranges)) {
-			ret = -EAGAIN;
-			goto out;
-		}
+		if (WARN_ON_ONCE(cmem->nr_ranges >= cmem->max_nr_ranges))
+			return -EAGAIN;
 
 		cmem->ranges[cmem->nr_ranges].start = start;
 		cmem->ranges[cmem->nr_ranges].end = end - 1;
 		cmem->nr_ranges++;
 	}
 
-	/* Exclude crashkernel region */
-	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
-	if (ret < 0)
-		goto out;
-
-	if (crashk_low_res.end) {
-		ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
-		if (ret < 0)
-			goto out;
-	}
-
-	ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
-
-out:
-	kfree(cmem);
-	return ret;
+	return 0;
 }
 
 /*
@@ -169,15 +150,12 @@ int load_other_segments(struct kimage *image,
 		void *headers;
 		unsigned long headers_sz;
 
-		get_online_mems();
-		ret = prepare_elf_headers(&headers, &headers_sz);
+		ret = crash_prepare_headers_locked(true, &headers, &headers_sz, NULL);
 		if (ret < 0) {
-			put_online_mems();
 			pr_err("Preparing elf core header failed\n");
 			goto out_err;
 		}
 
-		put_online_mems();
 		kbuf.buffer = headers;
 		kbuf.bufsz = headers_sz;
 		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
-- 
2.34.1