mm/vmalloc: remove vmap_area_list

Earlier, vmap_area_list is exported to vmcoreinfo so that makedumpfile get
the base address of vmalloc area.  Now, vmap_area_list is empty, so export
VMALLOC_START to vmcoreinfo instead, and remove vmap_area_list.

[urezki@gmail.com: fix a warning in the crash_save_vmcoreinfo_init()]
  Link: https://lkml.kernel.org/r/20240111192329.449189-1-urezki@gmail.com
Link: https://lkml.kernel.org/r/20240102184633.748113-6-urezki@gmail.comSigned-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/admin-guide/kdump/vmcoreinfo.rst

@@ -65,11 +65,11 @@ Defines the beginning of the text section. In general, _stext indicates
 the kernel start address. Used to convert a virtual address from the
 direct kernel map to a physical address.
 
-vmap_area_list
---------------
+VMALLOC_START
+-------------
 
-Stores the virtual area list. makedumpfile gets the vmalloc start value
-from this variable and its value is necessary for vmalloc translation.
+Stores the base address of vmalloc area. makedumpfile gets this value
+since is necessary for vmalloc translation.
 
 mem_map
 -------

arch/arm64/kernel/crash_core.c

@@ -23,7 +23,6 @@ void arch_crash_save_vmcoreinfo(void)
 	/* Please note VMCOREINFO_NUMBER() uses "%d", not "%x" */
 	vmcoreinfo_append_str("NUMBER(MODULES_VADDR)=0x%lx\n", MODULES_VADDR);
 	vmcoreinfo_append_str("NUMBER(MODULES_END)=0x%lx\n", MODULES_END);
-	vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START);
 	vmcoreinfo_append_str("NUMBER(VMALLOC_END)=0x%lx\n", VMALLOC_END);
 	vmcoreinfo_append_str("NUMBER(VMEMMAP_START)=0x%lx\n", VMEMMAP_START);
 	vmcoreinfo_append_str("NUMBER(VMEMMAP_END)=0x%lx\n", VMEMMAP_END);

arch/riscv/kernel/crash_core.c

@@ -8,7 +8,6 @@ void arch_crash_save_vmcoreinfo(void)
 	VMCOREINFO_NUMBER(phys_ram_base);
 
 	vmcoreinfo_append_str("NUMBER(PAGE_OFFSET)=0x%lx\n", PAGE_OFFSET);
-	vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START);
 	vmcoreinfo_append_str("NUMBER(VMALLOC_END)=0x%lx\n", VMALLOC_END);
 #ifdef CONFIG_MMU
 	VMCOREINFO_NUMBER(VA_BITS);

include/linux/vmalloc.h

@@ -253,7 +253,6 @@ extern long vread_iter(struct iov_iter *iter, const char *addr, size_t count);
 /*
  *	Internals.  Don't use..
  */
-extern struct list_head vmap_area_list;
 extern __init void vm_area_add_early(struct vm_struct *vm);
 extern __init void vm_area_register_early(struct vm_struct *vm, size_t align);
 

kernel/crash_core.c

@@ -748,7 +748,7 @@ static int __init crash_save_vmcoreinfo_init(void)
 	VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir);
 #endif
 	VMCOREINFO_SYMBOL(_stext);
-	VMCOREINFO_SYMBOL(vmap_area_list);
+	vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", (unsigned long) VMALLOC_START);
 
 #ifndef CONFIG_NUMA
 	VMCOREINFO_SYMBOL(mem_map);
@@ -789,8 +789,6 @@ static int __init crash_save_vmcoreinfo_init(void)
 	VMCOREINFO_OFFSET(free_area, free_list);
 	VMCOREINFO_OFFSET(list_head, next);
 	VMCOREINFO_OFFSET(list_head, prev);
-	VMCOREINFO_OFFSET(vmap_area, va_start);
-	VMCOREINFO_OFFSET(vmap_area, list);
 	VMCOREINFO_LENGTH(zone.free_area, NR_PAGE_ORDERS);
 	log_buf_vmcoreinfo_setup();
 	VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);

kernel/kallsyms_selftest.c

@@ -89,7 +89,6 @@ static struct test_item test_items[] = {
 	ITEM_DATA(kallsyms_test_var_data_static),
 	ITEM_DATA(kallsyms_test_var_bss),
 	ITEM_DATA(kallsyms_test_var_data),
-	ITEM_DATA(vmap_area_list),
 #endif
 };
 

mm/nommu.c

@@ -131,8 +131,6 @@ int follow_pfn(struct vm_area_struct *vma, unsigned long address,
 }
 EXPORT_SYMBOL(follow_pfn);
 
-LIST_HEAD(vmap_area_list);
-
 void vfree(const void *addr)
 {
 	kfree(addr);

mm/vmalloc.c

@@ -729,8 +729,6 @@ EXPORT_SYMBOL(vmalloc_to_pfn);
 
 
 static DEFINE_SPINLOCK(free_vmap_area_lock);
-/* Export for kexec only */
-LIST_HEAD(vmap_area_list);
 static bool vmap_initialized __read_mostly;
 
 static struct rb_root purge_vmap_area_root = RB_ROOT;