Re: [PATCH] io_uring/net: silence sparse warnings on address space

[Jens Axboe <axboe@kernel.dk>]

On 6/20/23 10:17?PM, Christoph Hellwig wrote:
> On Tue, Jun 20, 2023 at 04:55:05PM -0600, Jens Axboe wrote:
>> Rather than assign the user pointer to msghdr->msg_control, assign it
>> to msghdr->msg_control_user to make sparse happy. They are in a union
>> so the end result is the same, but let's avoid new sparse warnings and
>> squash this one.
> 
> Te patch looks good, but I think "silence sparse warning" is a horrible
> way to write a commit message.  Yes, you're silencing sparse, but sparse
> only complains because we have a type mismatch.
> 
> So the much better Subject would be something like: 
> 
> io_uring/net: use the correct msghdr union member in io_sendmsg_copy_hdr
> 
> Use msg_control_user to read the control message in io_sendmsg_copy_hdr
> as we expect a user pointer, not the kernel pointer in msg_control.
> The end result is the same, but this avoids a sparse addres space
> warning.
> 
> With that:
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>

You're totally right, that is a much better subject line. I've amended
the commit.

> (and it's really time we ger the __user and __bitwise annotations
> checked by hte actual compiler..)

That would indeed be nice... I know io_uring has some sparse complaints
on the __poll_t type that have been around forever, would be nice to get
those sorted and just in general ensure it's sparse clean. Then we could
start looking for new warnings at build time.

-- 
Jens Axboe