From: Jan Kara Subject: Re: [PATCH v2 2/2] ext2, ext4: use the super_block dax_device Date: Mon, 28 Aug 2017 10:27:24 +0200 Message-ID: <20170828082724.GA12609@quack2.suse.cz> References: <150389211501.25151.6477753201827914462.stgit@dwillia2-desk3.amr.corp.intel.com> <150389212595.25151.10721705529768874001.stgit@dwillia2-desk3.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Theodore Ts'o , linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, linux-xfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andreas Dilger , Jan Kara , linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, jack-AlSwsSmVLrQ@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, hch-jcswGhMUV9g@public.gmane.org To: Dan Williams Return-path: Content-Disposition: inline In-Reply-To: <150389212595.25151.10721705529768874001.stgit-p8uTFz9XbKj2zm6wflaqv1nYeNYlB/vhral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" List-Id: linux-ext4.vger.kernel.org On Sun 27-08-17 20:48:46, Dan Williams wrote: > The ->iomap_begin() operation is a hot path, and now that mount_bdev() > arranges for the dax_device to be populated in the super_block, we can > just reference that attribute directly rather than perform a new lookup. > > Cc: Jan Kara > Cc: "Theodore Ts'o" > Cc: Andreas Dilger > Reported-by: Christoph Hellwig > Signed-off-by: Dan Williams Looks good. You can add: Reviewed-by: Jan Kara Honza > --- > fs/ext2/inode.c | 10 ++-------- > fs/ext4/inode.c | 10 ++-------- > 2 files changed, 4 insertions(+), 16 deletions(-) > > diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c > index 30163d007b2f..7102b77a83c6 100644 > --- a/fs/ext2/inode.c > +++ b/fs/ext2/inode.c > @@ -800,7 +800,6 @@ int ext2_get_block(struct inode *inode, sector_t iblock, > static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > unsigned flags, struct iomap *iomap) > { > - struct block_device *bdev; > unsigned int blkbits = inode->i_blkbits; > unsigned long first_block = offset >> blkbits; > unsigned long max_blocks = (length + (1 << blkbits) - 1) >> blkbits; > @@ -814,13 +813,9 @@ static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > return ret; > > iomap->flags = 0; > - bdev = inode->i_sb->s_bdev; > - iomap->bdev = bdev; > + iomap->bdev = inode->i_sb->s_bdev; > iomap->offset = (u64)first_block << blkbits; > - if (blk_queue_dax(bdev->bd_queue)) > - iomap->dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name); > - else > - iomap->dax_dev = NULL; > + iomap->dax_dev = inode->i_sb->s_daxdev; > > if (ret == 0) { > iomap->type = IOMAP_HOLE; > @@ -842,7 +837,6 @@ static int > ext2_iomap_end(struct inode *inode, loff_t offset, loff_t length, > ssize_t written, unsigned flags, struct iomap *iomap) > { > - fs_put_dax(iomap->dax_dev); > if (iomap->type == IOMAP_MAPPED && > written < length && > (flags & IOMAP_WRITE)) > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index c774bdc22759..311690522366 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3404,7 +3404,6 @@ static int ext4_releasepage(struct page *page, gfp_t wait) > static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > unsigned flags, struct iomap *iomap) > { > - struct block_device *bdev; > unsigned int blkbits = inode->i_blkbits; > unsigned long first_block = offset >> blkbits; > unsigned long last_block = (offset + length - 1) >> blkbits; > @@ -3473,12 +3472,8 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > } > > iomap->flags = 0; > - bdev = inode->i_sb->s_bdev; > - iomap->bdev = bdev; > - if (blk_queue_dax(bdev->bd_queue)) > - iomap->dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name); > - else > - iomap->dax_dev = NULL; > + iomap->bdev = inode->i_sb->s_bdev; > + iomap->dax_dev = inode->i_sb->s_daxdev; > iomap->offset = first_block << blkbits; > > if (ret == 0) { > @@ -3511,7 +3506,6 @@ static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length, > int blkbits = inode->i_blkbits; > bool truncate = false; > > - fs_put_dax(iomap->dax_dev); > if (!(flags & IOMAP_WRITE) || (flags & IOMAP_FAULT)) > return 0; > > -- Jan Kara SUSE Labs, CR