From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0DD1C10F; Mon, 27 Nov 2023 05:07:30 -0800 (PST) Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Sf5Tl4wF0z4f3jJ0; Mon, 27 Nov 2023 21:07:23 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id 75CE61A0C58; Mon, 27 Nov 2023 21:07:26 +0800 (CST) Received: from [10.174.176.73] (unknown [10.174.176.73]) by APP1 (Coremail) with SMTP id cCh0CgDX2hCKlGRldTJXCA--.14854S3; Mon, 27 Nov 2023 21:07:25 +0800 (CST) Subject: Re: [PATCH block/for-next v2 01/16] block: add a new helper to get inode from block_device To: Christoph Hellwig , Yu Kuai Cc: ming.lei@redhat.com, axboe@kernel.dk, roger.pau@citrix.com, colyli@suse.de, kent.overstreet@gmail.com, joern@lazybastard.org, miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com, sth@linux.ibm.com, hoeppner@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, jejb@linux.ibm.com, martin.petersen@oracle.com, clm@fb.com, josef@toxicpanda.com, dsterba@suse.com, viro@zeniv.linux.org.uk, brauner@kernel.org, nico@fluxnic.net, xiang@kernel.org, chao@kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, agruenba@redhat.com, jack@suse.com, konishi.ryusuke@gmail.com, dchinner@redhat.com, linux@weissschuh.net, min15.li@samsung.com, dlemoal@kernel.org, willy@infradead.org, akpm@linux-foundation.org, hare@suse.de, p.raghav@samsung.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, linux-bcachefs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, gfs2@lists.linux.dev, linux-nilfs@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, "yukuai (C)" References: <20231127062116.2355129-1-yukuai1@huaweicloud.com> <20231127062116.2355129-2-yukuai1@huaweicloud.com> From: Yu Kuai Message-ID: <6acdeece-7163-3219-95e2-827e54eadd0c@huaweicloud.com> Date: Mon, 27 Nov 2023 21:07:22 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 Precedence: bulk X-Mailing-List: linux-bcache@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID:cCh0CgDX2hCKlGRldTJXCA--.14854S3 X-Coremail-Antispam: 1UD129KBjvJXoW7KF1fWFWkJw1kuFy8XF43KFg_yoW8KrWDp3 y7KFn8tw1DJryFgan7tw1jqrn0g3W7GrWUZ34rZrsxurZ8WFy2qF10krsrXFyIyr48Jw4I qF45AF43Xry2grJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9214x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvEwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7CjxVA2Y2ka 0xkIwI1lc7I2V7IY0VAS07AlzVAYIcxG8wCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7x kEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E 67AF67kF1VAFwI0_Wrv_Gr1UMIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF 4lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwCI42IY6xAIw20EY4v20xvaj40_WFyU JVCq3wCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I0E14v26rxl6s0DYx BIdaVFxhVjvjDU0xZFpf9x0JUd8n5UUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ Hi, ÔÚ 2023/11/27 15:21, Christoph Hellwig дµÀ: > On Mon, Nov 27, 2023 at 02:21:01PM +0800, Yu Kuai wrote: >> From: Yu Kuai >> >> block_devcie is allocated from bdev_alloc() by bdev_alloc_inode(), and >> currently block_device contains a pointer that point to the address of >> inode, while such inode is allocated together: > > This is going the wrong way. Nothing outside of core block layer code > should ever directly use the bdev inode. We've been rather sloppy > and added a lot of direct reference to it, but they really need to > go away and be replaced with well defined high level operation on > struct block_device. Once that is done we can remove the bd_inode > pointer, but replacing it with something that pokes even more deeply > into bdev internals is a bad idea. Thanks for the advice, however, after collecting how other modules are using bdev inode, I got two main questions: 1) Is't okay to add a new helper to pass in bdev for following apis? If so, then almost all the fs and driver can avoid to access bd_inode dirctly. errseq_check(&bdev->bd_inode->i_mapping->wb_err, wb_err); errseq_check_and_advance(&bdev->bd_inode->i_mapping->wb_err, &wb_err); mapping_gfp_constraint(bdev->bd_inode->i_mapping, gfp); i_size_read(bdev->bd_inode) find_get_page(bdev->bd_inode->i_mapping, offset); find_or_create_page(bdev->bd_inode->i_mapping, index, gfp); read_cache_page_gfp(bdev->bd_inode->i_mapping, index, gfp); invalidate_inode_pages2(bdev->bd_inode->i_mapping); invalidate_inode_pages2_range(bdev->bd_inode->i_mapping, start, end); read_mapping_folio(bdev->bd_inode->i_mapping, index, file); read_mapping_page(bdev->bd_inode->i_mapping, index, file); balance_dirty_pages_ratelimited(bdev->bd_inode->i_mapping) file_ra_state_init(ra, bdev->bd_inode->i_mapping); page_cache_sync_readahead(bdev->bd_inode->i_mapping, ra, file, index, req_count); inode_to_bdi(bdev->bd_inode) 2) For the file fs/buffer.c, there are some special usage like following that I don't think it's good to add a helper: spin_lock(&bd_inode->i_mapping->private_lock); Is't okay to move following apis from fs/buffer.c directly to block/bdev.c? __find_get_block bdev_getblk Thanks, Kuai > . >