linux-kernel - Re: [PATCH v3 05/11] mm/vmalloc: remove vmap_area

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Message-ID: <a5926122-cc27-43c0-b937-a70aa77a4005@lucifer.local>
Date: Tue, 16 Jan 2024 23:36:35 +0000
From: Lorenzo Stoakes <lstoakes@...il.com>
To: "Uladzislau Rezki (Sony)" <urezki@...il.com>
Cc: linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>, Baoquan He <bhe@...hat.com>,
	Christoph Hellwig <hch@...radead.org>,
	Matthew Wilcox <willy@...radead.org>,
	"Liam R . Howlett" <Liam.Howlett@...cle.com>,
	Dave Chinner <david@...morbit.com>,
	"Paul E . McKenney" <paulmck@...nel.org>,
	Joel Fernandes <joel@...lfernandes.org>,
	Oleksiy Avramchenko <oleksiy.avramchenko@...y.com>
Subject: Re: [PATCH v3 05/11] mm/vmalloc: remove vmap_area_list

On Tue, Jan 02, 2024 at 07:46:27PM +0100, Uladzislau Rezki (Sony) wrote:
> From: Baoquan He <bhe@...hat.com>
>
> 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.
>
> Signed-off-by: Baoquan He <bhe@...hat.com>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
> ---
>  Documentation/admin-guide/kdump/vmcoreinfo.rst | 8 ++++----
>  arch/arm64/kernel/crash_core.c                 | 1 -
>  arch/riscv/kernel/crash_core.c                 | 1 -
>  include/linux/vmalloc.h                        | 1 -
>  kernel/crash_core.c                            | 4 +---
>  kernel/kallsyms_selftest.c                     | 1 -
>  mm/nommu.c                                     | 2 --
>  mm/vmalloc.c                                   | 2 --
>  8 files changed, 5 insertions(+), 15 deletions(-)
>
> diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
> index 78e4d2e7ba14..df54fbeaaa16 100644
> --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
> +++ b/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
>  -------
> diff --git a/arch/arm64/kernel/crash_core.c b/arch/arm64/kernel/crash_core.c
> index 66cde752cd74..2a24199a9b81 100644
> --- a/arch/arm64/kernel/crash_core.c
> +++ b/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);
> diff --git a/arch/riscv/kernel/crash_core.c b/arch/riscv/kernel/crash_core.c
> index 8706736fd4e2..d18d529fd9b9 100644
> --- a/arch/riscv/kernel/crash_core.c
> +++ b/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);
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index c720be70c8dd..91810b4e9510 100644
> --- a/include/linux/vmalloc.h
> +++ b/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);
>
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index d4313b53837e..b427f4a3b156 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -759,7 +759,7 @@ 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", VMALLOC_START);
>
>  #ifndef CONFIG_NUMA
>  	VMCOREINFO_SYMBOL(mem_map);
> @@ -800,8 +800,6 @@ 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, MAX_ORDER + 1);
>  	log_buf_vmcoreinfo_setup();
>  	VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
> diff --git a/kernel/kallsyms_selftest.c b/kernel/kallsyms_selftest.c
> index b4cac76ea5e9..8a689b4ff4f9 100644
> --- a/kernel/kallsyms_selftest.c
> +++ b/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
>  };
>
> diff --git a/mm/nommu.c b/mm/nommu.c
> index b6dc558d3144..5ec8f44e7ce9 100644
> --- a/mm/nommu.c
> +++ b/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);
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 786ecb18ae22..8c01f2225ef7 100644
> --- a/mm/vmalloc.c
> +++ b/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;
> --
> 2.39.2
>

Looks good to me, I'm not _hugely_ familiar with this crash core stuff so:

Acked-by: Lorenzo Stoakes <lstoakes@...il.com>