Re: [PATCH 1/2] super: massage wait event mechanism

[Christoph Hellwig <hch@lst.de>]

On Mon, Nov 27, 2023 at 12:51:30PM +0100, Christian Brauner wrote:
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> ---
>  fs/super.c | 51 ++++++++++++++-------------------------------------
>  1 file changed, 14 insertions(+), 37 deletions(-)
> 
> diff --git a/fs/super.c b/fs/super.c
> index aa4e5c11ee32..f3227b22879d 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -81,16 +81,13 @@ static inline void super_unlock_shared(struct super_block *sb)
>  	super_unlock(sb, false);
>  }
>  
> +static bool super_load_flags(const struct super_block *sb, unsigned int flags)
>  {
>  	/*
>  	 * Pairs with smp_store_release() in super_wake() and ensures
> +	 * that we see @flags after we're woken.
>  	 */
> +	return smp_load_acquire(&sb->s_flags) & flags;

I find the name for this helper very confusing.  Yes, eventually it
is clear that the load maps to a load instruction with acquire semantics
here, but it's a really unusual naming I think.  Unfortunately I can't
offer a better one either.

Otherwise this looks good except for the fact that I really hate
code using smp_load_acquire / smp_store_release directly because of
all the mental load it causes.