linux-kernel - Re: [PATCH v4] eventfd: convert to f_op->read

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Message-ID: <435c171c-37aa-8f7d-c506-d1e8f07f4bc7@kernel.dk>
Date:   Sun, 3 May 2020 08:42:41 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Al Viro <viro@...iv.linux.org.uk>
Cc:     linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4] eventfd: convert to f_op->read_iter()

On 5/3/20 7:46 AM, Al Viro wrote:
> On Fri, May 01, 2020 at 05:54:09PM -0600, Jens Axboe wrote:
>> On 5/1/20 5:12 PM, Al Viro wrote:
>>> On Fri, May 01, 2020 at 01:11:09PM -0600, Jens Axboe wrote:
>>>> +	flags &= EFD_SHARED_FCNTL_FLAGS;
>>>> +	flags |= O_RDWR;
>>>> +	fd = get_unused_fd_flags(flags);
>>>>  	if (fd < 0)
>>>> -		eventfd_free_ctx(ctx);
>>>> +		goto err;
>>>> +
>>>> +	file = anon_inode_getfile("[eventfd]", &eventfd_fops, ctx, flags);
>>>> +	if (IS_ERR(file)) {
>>>> +		put_unused_fd(fd);
>>>> +		fd = PTR_ERR(file);
>>>> +		goto err;
>>>> +	}
>>>>  
>>>> +	file->f_mode |= FMODE_NOWAIT;
>>>> +	fd_install(fd, file);
>>>> +	return fd;
>>>> +err:
>>>> +	eventfd_free_ctx(ctx);
>>>>  	return fd;
>>>>  }
>>>
>>> Looks sane...  I can take it via vfs.git, or leave it for you if you
>>> have other stuff in the same area...
>>
>> Would be great if you can queue it up in vfs.git, thanks! Don't have
>> anything else that'd conflict with this.
> 
> Applied; BTW, what happens if
>         ctx->id = ida_simple_get(&eventfd_ida, 0, 0, GFP_KERNEL);
> fails?  Quitely succeed with BS value (-ENOSPC/-ENOMEM) shown by
> eventfd_show_fdinfo()?

Huh yeah that's odd, not sure how I missed that when touching code
near it. Want a followup patch to fix that issue?

-- 
Jens Axboe