linux-kernel - Re: [PATCH] fs:aio: Remove TODO comment suggesting hash or array usage in io

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Message-ID: <20241112120252.a75tg4xqszn7nou3@quack3>
Date: Tue, 12 Nov 2024 13:02:52 +0100
From: Jan Kara <jack@...e.cz>
To: Mohammed Anees <pvmohammedanees2003@...il.com>
Cc: jmoyer@...hat.com, bcrl@...ck.org, brauner@...nel.org, jack@...e.cz,
	viro@...iv.linux.org.uk, willy@...radead.org, linux-aio@...ck.org,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fs:aio: Remove TODO comment suggesting hash or array
 usage in  io_cancel()

On Tue 12-11-24 17:08:34, Mohammed Anees wrote:
> The comment suggests a hash or array approach to
> store the active requests. Currently it iterates
> through all the active requests and when found
> deletes the requested request, in the linked list.
> However io_cancel() isn’t a frequently used operation,
> and optimizing it wouldn’t bring a substantial benefit
> to real users and the increased complexity of maintaining
> a hashtable for this would be significant and will slow
> down other operation. Therefore remove this TODO 
> to avoid people spending time improving this.
> 
> Signed-off-by: Mohammed Anees <pvmohammedanees2003@...il.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/aio.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/fs/aio.c b/fs/aio.c
> index e8920178b50f..72e3970f4225 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -2191,7 +2191,6 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
>  		return -EINVAL;
>  
>  	spin_lock_irq(&ctx->ctx_lock);
> -	/* TODO: use a hash or array, this sucks. */
>  	list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
>  		if (kiocb->ki_res.obj == obj) {
>  			ret = kiocb->ki_cancel(&kiocb->rw);
> -- 
> 2.47.0
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR