Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [dm-devel] [PATCH 06/18] bvec: add a bvec_kmap_local helper
To:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Thomas Gleixner <tglx@linutronix.de>
Cc:     linux-arch@vger.kernel.org, linux-block@vger.kernel.org,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>,
        Mike Snitzer <snitzer@redhat.com>,
        Geoff Levand <geoff@infradead.org>,
        linuxppc-dev@lists.ozlabs.org, linux-mips@vger.kernel.org,
        Dongsheng Yang <dongsheng.yang@easystack.cn>,
        linux-kernel@vger.kernel.org,
        "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
        dm-devel@redhat.com, Ilya Dryomov <idryomov@gmail.com>,
        Ira Weiny <ira.weiny@intel.com>, ceph-devel@vger.kernel.org
References: <20210615132456.753241-1-hch@lst.de>
 <20210615132456.753241-7-hch@lst.de>
From:   Bart Van Assche <bvanassche@acm.org>
Message-ID: <244b92f2-7921-7f33-b83f-66f3fff57696@acm.org>
Date:   Wed, 16 Jun 2021 09:52:18 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.11.0
MIME-Version: 1.0
In-Reply-To: <20210615132456.753241-7-hch@lst.de>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 6/15/21 6:24 AM, Christoph Hellwig wrote:
> +/**
> + * bvec_kmap_local - map a bvec into the kernel virtual address space
> + * @bvec: bvec to map
> + *
> + * Must be called on single-page bvecs only.  Call kunmap_local on the returned
> + * address to unmap.
> + */
> +static inline void *bvec_kmap_local(struct bio_vec *bvec)
> +{
> +	return kmap_local_page(bvec->bv_page) + bvec->bv_offset;
> +}

Hi Christoph,

Would it be appropriate to add WARN_ON_ONCE(bvec->bv_offset >=
PAGE_SIZE) in this function?

Thanks,

Bart.