Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <e2c63348-fbf9-0d2a-7c09-ee14f6106770@redhat.com>
Date:   Wed, 22 Mar 2023 12:12:09 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.9.0
Subject: Re: [PATCH v4 2/4] fs/proc/kcore: convert read_kcore() to
 read_kcore_iter()
Content-Language: en-US
To:     Lorenzo Stoakes <lstoakes@gmail.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Baoquan He <bhe@redhat.com>, Uladzislau Rezki <urezki@gmail.com>,
        Matthew Wilcox <willy@infradead.org>,
        Liu Shixin <liushixin2@huawei.com>,
        Jiri Olsa <jolsa@kernel.org>, Jens Axboe <axboe@kernel.dk>,
        Alexander Viro <viro@zeniv.linux.org.uk>
References: <cover.1679431886.git.lstoakes@gmail.com>
 <a84da6cc458b44d949058b5f475ed3225008cfd9.1679431886.git.lstoakes@gmail.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <a84da6cc458b44d949058b5f475ed3225008cfd9.1679431886.git.lstoakes@gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 21.03.23 21:54, Lorenzo Stoakes wrote:
> Now we have eliminated spinlocks from the vread() case, convert
> read_kcore() to read_kcore_iter().
> 
> For the time being we still use a bounce buffer for vread(), however in the
> next patch we will convert this to interact directly with the iterator and
> eliminate the bounce buffer altogether.
> 
> Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
> ---
>   fs/proc/kcore.c | 58 ++++++++++++++++++++++++-------------------------
>   1 file changed, 29 insertions(+), 29 deletions(-)
> 
> diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
> index 556f310d6aa4..25e0eeb8d498 100644
> --- a/fs/proc/kcore.c
> +++ b/fs/proc/kcore.c
> @@ -24,7 +24,7 @@
>   #include <linux/memblock.h>
>   #include <linux/init.h>
>   #include <linux/slab.h>
> -#include <linux/uaccess.h>
> +#include <linux/uio.h>
>   #include <asm/io.h>
>   #include <linux/list.h>
>   #include <linux/ioport.h>
> @@ -308,9 +308,12 @@ static void append_kcore_note(char *notes, size_t *i, const char *name,
>   }
>   
>   static ssize_t
> -read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
> +read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
>   {
> +	struct file *file = iocb->ki_filp;
>   	char *buf = file->private_data;
> +	loff_t *ppos = &iocb->ki_pos;

Not renaming fpos -> ppos in this patch would result in less noise in 
this patch. Just like you didn't rename buflen.

In general, LGTM

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb