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@gmail.com>
---
 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

On Tue, 12 Nov 2024 17:08:34 +0530, 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.
> 
> [...]

Applied to the vfs.misc branch of the vfs/vfs.git tree.
Patches in the vfs.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.misc

[1/1] fs:aio: Remove TODO comment suggesting hash or array usage in io_cancel()
      https://git.kernel.org/vfs/vfs/c/27e4f4fa65c2

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@gmail.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.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@suse.com>
SUSE Labs, CR