From patchwork Sat Apr 9 04:50:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 559357 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BFD15C4332F for ; Sat, 9 Apr 2022 04:54:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241246AbiDIE4c (ORCPT ); Sat, 9 Apr 2022 00:56:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241245AbiDIEzb (ORCPT ); Sat, 9 Apr 2022 00:55:31 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77E2CBC857; Fri, 8 Apr 2022 21:52:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc: To:From:Sender:Reply-To:Content-ID:Content-Description; bh=pVDwXB6PltgVZkC3rRdiaCUdLly1SPIvqpMIXjtbaqw=; b=jqUA+AmRXIWodbokKUQJY0RX0L 3iRxTxojZgoAr0BJQ1ponT4HGyJF9P/dLKgG3mgDVBzT9ZC3GJ4VXksCd7CI4pp2deGOMuRnO4dJZ tYjvlBna5K+2SqqA4cHi6bHT3o1vwsbWhi8IrSk8cEbLbPYhU9Q1bHhBT4/6s3jRpSUTvMY8j6m9y ZXrNmSY5/qE17M860l2JtYPEp4Qs2IucObE64GZleGfFuLyLOimXHvRbrt+CUdmhLio0qwks9xvBt Vg5wC+6v6SCxOh06XmFFo2NPgfa5H4+lhNehhWJUBtAxZ5KuAcLte2n3q/5mzTUIyBnf71eMj2a2Y UapUGRFw==; Received: from 213-147-167-116.nat.highway.webapn.at ([213.147.167.116] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nd358-0021hI-T6; Sat, 09 Apr 2022 04:52:19 +0000 From: Christoph Hellwig To: Jens Axboe Cc: dm-devel@redhat.com, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-um@lists.infradead.org, linux-block@vger.kernel.org, drbd-dev@lists.linbit.com, nbd@other.debian.org, ceph-devel@vger.kernel.org, virtualization@lists.linux-foundation.org, xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, linux-raid@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mtd@lists.infradead.org, linux-nvme@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, jfs-discussion@lists.sourceforge.net, linux-nilfs@vger.kernel.org, ntfs3@lists.linux.dev, ocfs2-devel@oss.oracle.com, linux-mm@kvack.org, "Martin K . Petersen" , =?utf-8?q?Christoph_B?= =?utf-8?q?=C3=B6hmwalder?= , Ryusuke Konishi , David Sterba Subject: [PATCH 25/27] block: add a bdev_discard_granularity helper Date: Sat, 9 Apr 2022 06:50:41 +0200 Message-Id: <20220409045043.23593-26-hch@lst.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220409045043.23593-1-hch@lst.de> References: <20220409045043.23593-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org Abstract away implementation details from file systems by providing a block_device based helper to retrieve the discard granularity. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Acked-by: Christoph Böhmwalder [btrfs] Acked-by: Ryusuke Konishi Acked-by: David Sterba [btrfs] --- block/blk-lib.c | 5 ++--- drivers/block/drbd/drbd_nl.c | 9 +++++---- drivers/block/drbd/drbd_receiver.c | 3 +-- drivers/block/loop.c | 2 +- drivers/target/target_core_device.c | 3 +-- fs/btrfs/ioctl.c | 12 ++++-------- fs/exfat/file.c | 3 +-- fs/ext4/mballoc.c | 6 +++--- fs/f2fs/file.c | 3 +-- fs/fat/file.c | 3 +-- fs/gfs2/rgrp.c | 7 +++---- fs/jfs/ioctl.c | 3 +-- fs/nilfs2/ioctl.c | 4 ++-- fs/ntfs3/file.c | 4 ++-- fs/ntfs3/super.c | 6 ++---- fs/ocfs2/ioctl.c | 3 +-- fs/xfs/xfs_discard.c | 4 ++-- include/linux/blkdev.h | 5 +++++ 18 files changed, 38 insertions(+), 47 deletions(-) diff --git a/block/blk-lib.c b/block/blk-lib.c index 8b4b66d3a9bfc..43aa4d7fe859f 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -12,8 +12,7 @@ static sector_t bio_discard_limit(struct block_device *bdev, sector_t sector) { - unsigned int discard_granularity = - bdev_get_queue(bdev)->limits.discard_granularity; + unsigned int discard_granularity = bdev_discard_granularity(bdev); sector_t granularity_aligned_sector; if (bdev_is_partition(bdev)) @@ -59,7 +58,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, } /* In case the discard granularity isn't set by buggy device driver */ - if (WARN_ON_ONCE(!q->limits.discard_granularity)) { + if (WARN_ON_ONCE(!bdev_discard_granularity(bdev))) { char dev_name[BDEVNAME_SIZE]; bdevname(bdev, dev_name); diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index b55e5fcc21e1f..0b3e43be6414d 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -1425,7 +1425,6 @@ static void sanitize_disk_conf(struct drbd_device *device, struct disk_conf *dis struct drbd_backing_dev *nbc) { struct block_device *bdev = nbc->backing_bdev; - struct request_queue *q = bdev->bd_disk->queue; if (disk_conf->al_extents < DRBD_AL_EXTENTS_MIN) disk_conf->al_extents = DRBD_AL_EXTENTS_MIN; @@ -1442,12 +1441,14 @@ static void sanitize_disk_conf(struct drbd_device *device, struct disk_conf *dis if (disk_conf->rs_discard_granularity) { int orig_value = disk_conf->rs_discard_granularity; sector_t discard_size = bdev_max_discard_sectors(bdev) << 9; + unsigned int discard_granularity = bdev_discard_granularity(bdev); int remainder; - if (q->limits.discard_granularity > disk_conf->rs_discard_granularity) - disk_conf->rs_discard_granularity = q->limits.discard_granularity; + if (discard_granularity > disk_conf->rs_discard_granularity) + disk_conf->rs_discard_granularity = discard_granularity; - remainder = disk_conf->rs_discard_granularity % q->limits.discard_granularity; + remainder = disk_conf->rs_discard_granularity % + discard_granularity; disk_conf->rs_discard_granularity += remainder; if (disk_conf->rs_discard_granularity > discard_size) diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 8a4a47da56fe9..275c53c7b629e 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -1511,7 +1511,6 @@ void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backin int drbd_issue_discard_or_zero_out(struct drbd_device *device, sector_t start, unsigned int nr_sectors, int flags) { struct block_device *bdev = device->ldev->backing_bdev; - struct request_queue *q = bdev_get_queue(bdev); sector_t tmp, nr; unsigned int max_discard_sectors, granularity; int alignment; @@ -1521,7 +1520,7 @@ int drbd_issue_discard_or_zero_out(struct drbd_device *device, sector_t start, u goto zero_out; /* Zero-sector (unknown) and one-sector granularities are the same. */ - granularity = max(q->limits.discard_granularity >> 9, 1U); + granularity = max(bdev_discard_granularity(bdev) >> 9, 1U); alignment = (bdev_discard_alignment(bdev) >> 9) % granularity; max_discard_sectors = min(bdev_max_discard_sectors(bdev), (1U << 22)); diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 0e061c9896eff..976cf987b3920 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -759,7 +759,7 @@ static void loop_config_discard(struct loop_device *lo) struct request_queue *backingq = bdev_get_queue(I_BDEV(inode)); max_discard_sectors = backingq->limits.max_write_zeroes_sectors; - granularity = backingq->limits.discard_granularity ?: + granularity = bdev_discard_granularity(I_BDEV(inode)) ?: queue_physical_block_size(backingq); /* diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index 6cb9f87843278..25f33eb25337c 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -835,7 +835,6 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name) bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib, struct block_device *bdev) { - struct request_queue *q = bdev_get_queue(bdev); int block_size = bdev_logical_block_size(bdev); if (!bdev_max_discard_sectors(bdev)) @@ -847,7 +846,7 @@ bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib, * Currently hardcoded to 1 in Linux/SCSI code.. */ attrib->max_unmap_block_desc_count = 1; - attrib->unmap_granularity = q->limits.discard_granularity / block_size; + attrib->unmap_granularity = bdev_discard_granularity(bdev) / block_size; attrib->unmap_granularity_alignment = bdev_discard_alignment(bdev) / block_size; return true; diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 096bb0da03f1c..70765d59616a5 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -468,7 +468,6 @@ static noinline int btrfs_ioctl_fitrim(struct btrfs_fs_info *fs_info, void __user *arg) { struct btrfs_device *device; - struct request_queue *q; struct fstrim_range range; u64 minlen = ULLONG_MAX; u64 num_devices = 0; @@ -498,14 +497,11 @@ static noinline int btrfs_ioctl_fitrim(struct btrfs_fs_info *fs_info, rcu_read_lock(); list_for_each_entry_rcu(device, &fs_info->fs_devices->devices, dev_list) { - if (!device->bdev) + if (!device->bdev || !bdev_max_discard_sectors(device->bdev)) continue; - q = bdev_get_queue(device->bdev); - if (bdev_max_discard_sectors(device->bdev)) { - num_devices++; - minlen = min_t(u64, q->limits.discard_granularity, - minlen); - } + num_devices++; + minlen = min_t(u64, bdev_discard_granularity(device->bdev), + minlen); } rcu_read_unlock(); diff --git a/fs/exfat/file.c b/fs/exfat/file.c index 765e4f63dd18d..20d4e47f57ab2 100644 --- a/fs/exfat/file.c +++ b/fs/exfat/file.c @@ -351,7 +351,6 @@ int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg) { - struct request_queue *q = bdev_get_queue(inode->i_sb->s_bdev); struct fstrim_range range; int ret = 0; @@ -365,7 +364,7 @@ static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg) return -EFAULT; range.minlen = max_t(unsigned int, range.minlen, - q->limits.discard_granularity); + bdev_discard_granularity(inode->i_sb->s_bdev)); ret = exfat_trim_fs(inode, &range); if (ret < 0) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index c3668c977cd99..6d1820536d88d 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -6455,7 +6455,7 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, */ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) { - struct request_queue *q = bdev_get_queue(sb->s_bdev); + unsigned int discard_granularity = bdev_discard_granularity(sb->s_bdev); struct ext4_group_info *grp; ext4_group_t group, first_group, last_group; ext4_grpblk_t cnt = 0, first_cluster, last_cluster; @@ -6475,9 +6475,9 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) range->len < sb->s_blocksize) return -EINVAL; /* No point to try to trim less than discard granularity */ - if (range->minlen < q->limits.discard_granularity) { + if (range->minlen < discard_granularity) { minlen = EXT4_NUM_B2C(EXT4_SB(sb), - q->limits.discard_granularity >> sb->s_blocksize_bits); + discard_granularity >> sb->s_blocksize_bits); if (minlen > EXT4_CLUSTERS_PER_GROUP(sb)) goto out; } diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 5b89af0f27f05..8053d99f3920b 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -2285,7 +2285,6 @@ static int f2fs_ioc_fitrim(struct file *filp, unsigned long arg) { struct inode *inode = file_inode(filp); struct super_block *sb = inode->i_sb; - struct request_queue *q = bdev_get_queue(sb->s_bdev); struct fstrim_range range; int ret; @@ -2304,7 +2303,7 @@ static int f2fs_ioc_fitrim(struct file *filp, unsigned long arg) return ret; range.minlen = max((unsigned int)range.minlen, - q->limits.discard_granularity); + bdev_discard_granularity(sb->s_bdev)); ret = f2fs_trim_fs(F2FS_SB(sb), &range); mnt_drop_write_file(filp); if (ret < 0) diff --git a/fs/fat/file.c b/fs/fat/file.c index e4c7d10e80129..bf91f977debea 100644 --- a/fs/fat/file.c +++ b/fs/fat/file.c @@ -127,7 +127,6 @@ static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg) struct super_block *sb = inode->i_sb; struct fstrim_range __user *user_range; struct fstrim_range range; - struct request_queue *q = bdev_get_queue(sb->s_bdev); int err; if (!capable(CAP_SYS_ADMIN)) @@ -141,7 +140,7 @@ static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg) return -EFAULT; range.minlen = max_t(unsigned int, range.minlen, - q->limits.discard_granularity); + bdev_discard_granularity(sb->s_bdev)); err = fat_trim_fs(inode, &range); if (err < 0) diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 7f20ac9133bc6..6d26bb5254844 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -1386,7 +1386,7 @@ int gfs2_fitrim(struct file *filp, void __user *argp) { struct inode *inode = file_inode(filp); struct gfs2_sbd *sdp = GFS2_SB(inode); - struct request_queue *q = bdev_get_queue(sdp->sd_vfs->s_bdev); + struct block_device *bdev = sdp->sd_vfs->s_bdev; struct buffer_head *bh; struct gfs2_rgrpd *rgd; struct gfs2_rgrpd *rgd_end; @@ -1405,7 +1405,7 @@ int gfs2_fitrim(struct file *filp, void __user *argp) if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) return -EROFS; - if (!bdev_max_discard_sectors(sdp->sd_vfs->s_bdev)) + if (!bdev_max_discard_sectors(bdev)) return -EOPNOTSUPP; if (copy_from_user(&r, argp, sizeof(r))) @@ -1418,8 +1418,7 @@ int gfs2_fitrim(struct file *filp, void __user *argp) start = r.start >> bs_shift; end = start + (r.len >> bs_shift); minlen = max_t(u64, r.minlen, sdp->sd_sb.sb_bsize); - minlen = max_t(u64, minlen, - q->limits.discard_granularity) >> bs_shift; + minlen = max_t(u64, minlen, bdev_discard_granularity(bdev)) >> bs_shift; if (end <= start || minlen > sdp->sd_max_rg_data) return -EINVAL; diff --git a/fs/jfs/ioctl.c b/fs/jfs/ioctl.c index 357ae6e5c36ec..1e7b177ece605 100644 --- a/fs/jfs/ioctl.c +++ b/fs/jfs/ioctl.c @@ -110,7 +110,6 @@ long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) case FITRIM: { struct super_block *sb = inode->i_sb; - struct request_queue *q = bdev_get_queue(sb->s_bdev); struct fstrim_range range; s64 ret = 0; @@ -127,7 +126,7 @@ long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) return -EFAULT; range.minlen = max_t(unsigned int, range.minlen, - q->limits.discard_granularity); + bdev_discard_granularity(sb->s_bdev)); ret = jfs_ioc_trim(inode, &range); if (ret < 0) diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c index 52b73f558fcb1..87e1004b606d2 100644 --- a/fs/nilfs2/ioctl.c +++ b/fs/nilfs2/ioctl.c @@ -1052,7 +1052,6 @@ static int nilfs_ioctl_resize(struct inode *inode, struct file *filp, static int nilfs_ioctl_trim_fs(struct inode *inode, void __user *argp) { struct the_nilfs *nilfs = inode->i_sb->s_fs_info; - struct request_queue *q = bdev_get_queue(nilfs->ns_bdev); struct fstrim_range range; int ret; @@ -1065,7 +1064,8 @@ static int nilfs_ioctl_trim_fs(struct inode *inode, void __user *argp) if (copy_from_user(&range, argp, sizeof(range))) return -EFAULT; - range.minlen = max_t(u64, range.minlen, q->limits.discard_granularity); + range.minlen = max_t(u64, range.minlen, + bdev_discard_granularity(nilfs->ns_bdev)); down_read(&nilfs->ns_segctor_sem); ret = nilfs_sufile_trim_fs(nilfs->ns_sufile, &range); diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c index e763236169331..15806eeae217a 100644 --- a/fs/ntfs3/file.c +++ b/fs/ntfs3/file.c @@ -22,7 +22,6 @@ static int ntfs_ioctl_fitrim(struct ntfs_sb_info *sbi, unsigned long arg) { struct fstrim_range __user *user_range; struct fstrim_range range; - struct request_queue *q = bdev_get_queue(sbi->sb->s_bdev); int err; if (!capable(CAP_SYS_ADMIN)) @@ -35,7 +34,8 @@ static int ntfs_ioctl_fitrim(struct ntfs_sb_info *sbi, unsigned long arg) if (copy_from_user(&range, user_range, sizeof(range))) return -EFAULT; - range.minlen = max_t(u32, range.minlen, q->limits.discard_granularity); + range.minlen = max_t(u32, range.minlen, + bdev_discard_granularity(sbi->sb->s_bdev)); err = ntfs_trim_fs(sbi, &range); if (err < 0) diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c index c734085bcce4a..5f2e414cfa79b 100644 --- a/fs/ntfs3/super.c +++ b/fs/ntfs3/super.c @@ -882,7 +882,6 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc) int err; struct ntfs_sb_info *sbi = sb->s_fs_info; struct block_device *bdev = sb->s_bdev; - struct request_queue *rq; struct inode *inode; struct ntfs_inode *ni; size_t i, tt; @@ -912,9 +911,8 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc) goto out; } - rq = bdev_get_queue(bdev); - if (bdev_max_discard_sectors(bdev) && rq->limits.discard_granularity) { - sbi->discard_granularity = rq->limits.discard_granularity; + if (bdev_max_discard_sectors(bdev) && bdev_discard_granularity(bdev)) { + sbi->discard_granularity = bdev_discard_granularity(bdev); sbi->discard_granularity_mask_inv = ~(u64)(sbi->discard_granularity - 1); } diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c index 9b78ef103ada6..afd54ec661030 100644 --- a/fs/ocfs2/ioctl.c +++ b/fs/ocfs2/ioctl.c @@ -903,7 +903,6 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) case FITRIM: { struct super_block *sb = inode->i_sb; - struct request_queue *q = bdev_get_queue(sb->s_bdev); struct fstrim_range range; int ret = 0; @@ -916,7 +915,7 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) if (copy_from_user(&range, argp, sizeof(range))) return -EFAULT; - range.minlen = max_t(u64, q->limits.discard_granularity, + range.minlen = max_t(u64, bdev_discard_granularity(sb->s_bdev), range.minlen); ret = ocfs2_trim_fs(sb, &range); if (ret < 0) diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c index a4e6609d616b7..e2ada115c23f9 100644 --- a/fs/xfs/xfs_discard.c +++ b/fs/xfs/xfs_discard.c @@ -152,8 +152,8 @@ xfs_ioc_trim( struct xfs_mount *mp, struct fstrim_range __user *urange) { - struct request_queue *q = bdev_get_queue(mp->m_ddev_targp->bt_bdev); - unsigned int granularity = q->limits.discard_granularity; + unsigned int granularity = + bdev_discard_granularity(mp->m_ddev_targp->bt_bdev); struct fstrim_range range; xfs_daddr_t start, end, minlen; xfs_agnumber_t start_agno, end_agno, agno; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 767ab22e1052a..f1cf557ea20ef 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1257,6 +1257,11 @@ static inline unsigned int bdev_max_discard_sectors(struct block_device *bdev) return bdev_get_queue(bdev)->limits.max_discard_sectors; } +static inline unsigned int bdev_discard_granularity(struct block_device *bdev) +{ + return bdev_get_queue(bdev)->limits.discard_granularity; +} + static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev) { struct request_queue *q = bdev_get_queue(bdev);