On Thu, Aug 15, 2019 at 02:04:53AM +0000, Vladimir Panteleev wrote:
> - Avoid an allocation;
> - Properly handle non-numerical argument and garbage after numerical
> argument.
>
> Signed-off-by: Vladimir Panteleev <git@xxxxxxxxxxxxxxxxxx>
> ---
> fs/btrfs/super.c | 24 +++++++++---------------
> 1 file changed, 9 insertions(+), 15 deletions(-)
>
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index f56617dfb3cf..6fe8ef6667f3 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -426,7 +426,7 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
> unsigned long new_flags)
> {
> substring_t args[MAX_OPT_ARGS];
> - char *p, *num;
> + char *p, *retptr;
> u64 cache_gen;
> int intarg;
> int ret = 0;
> @@ -630,22 +630,16 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
> info->thread_pool_size = intarg;
> break;
> case Opt_max_inline:
> - num = match_strdup(&args[0]);
> - if (num) {
> - info->max_inline = memparse(num, NULL);
> - kfree(num);
> -
> - if (info->max_inline) {
> - info->max_inline = min_t(u64,
> - info->max_inline,
> - info->sectorsize);
> - }
> - btrfs_info(info, "max_inline at %llu",
> - info->max_inline);
> - } else {
> - ret = -ENOMEM;
> + info->max_inline = memparse(args[0].from, &retptr);
I don't think this is a good idea, match_strdup takes an opaque type
substring_t that is used by the parser. So accessing ::from directly in
memparse does not respect the API boundary. I've checked some other
usages in the tree and the match_strdup/memparse/kstrtoull is quite
common.
