Messages in this thread | | | Date | Tue, 10 May 2016 16:21:19 +0200 | From | Jan Kara <> | Subject | Re: [PATCH v5 4/5] dax: for truncate/hole-punch, do zeroing through the driver if possible |
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On Fri 06-05-16 15:53:10, Vishal Verma wrote: > +static bool dax_range_is_aligned(struct block_device *bdev, > + struct blk_dax_ctl *dax, unsigned int offset, > + unsigned int length) > +{ > + unsigned short sector_size = bdev_logical_block_size(bdev); > + > + if (((u64)dax->addr + offset) % sector_size) > + return false; > + if (length % sector_size) > + return false;
sector_size should better be a power of two so you can save some cycles by using & instead of %.
> @@ -1240,11 +1254,17 @@ int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length, > .size = PAGE_SIZE, > }; > > - if (dax_map_atomic(bdev, &dax) < 0) > - return PTR_ERR(dax.addr); > - clear_pmem(dax.addr + offset, length); > - wmb_pmem(); > - dax_unmap_atomic(bdev, &dax); > + if (dax_range_is_aligned(bdev, &dax, offset, length)) > + return blkdev_issue_zeroout(bdev, dax.sector, > + length / bdev_logical_block_size(bdev), > + GFP_NOFS, true);
This is actually wrong. blkdev_issue_zeroout() expects length to be simply in units of 512-bytes. So you need length >> 9 here.
Honza -- Jan Kara <jack@suse.com> SUSE Labs, CR
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