Re: [PATCH v21 1/5] kdump: return -ENOENT if required cmdline option does not exist

Baoquan He
2022-03-15T11:58:09Z

On 02/27/22 at 11:07am, Zhen Lei wrote:
> The crashkernel=Y,low is an optional command-line option. When it doesn't
> exist, kernel will try to allocate minimum required memory below 4G
> automatically. Give it a unique error code to distinguish it from other
> error scenarios.
>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
> kernel/crash_core.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 256cf6db573cd09..4d57c03714f4e13 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -243,9 +243,8 @@ static int __init __parse_crashkernel(char *cmdline,
> *crash_base = 0;
>
> ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
> -
> if (!ck_cmdline)
> - return -EINVAL;
> + return -ENOENT;

Firstly, I am not sure if '-ENOENT' is a right value to return. From the
code comment of ENOENT, it's used for file or dir?
#define ENOENT 2 /* No such file or directory */

Secondly, we ever discussed the case including
- no crashkernel=,low is provided;
- messy code is provied, e.g crashkernel=aaaaaabbbb,low

The 2nd one is not handled in this patchset. How about taking the
handling into another round of patches. This patchset just adds
crashkernel=,high purely.

>
> ck_cmdline += strlen(name);
>
> --
> 2.25.1
>