On Sat, Jan 28, 2017 at 12:36:58AM -0800, Dan Williams wrote: > Provide a replacement for bdev_direct_access() that uses > dax_operations.direct_access() instead of > block_device_operations.direct_access(). Once all consumers of the old > api have been converted bdev_direct_access() will be deleted. > > Given that block device partitioning decisions can cause dax page > alignment constraints to be violated we still need to validate the > block_device before calling the dax ->direct_access method. > > Signed-off-by: Dan Williams <[email protected]> > --- > block/Kconfig | 1 + > drivers/dax/super.c | 33 +++++++++++++++++++++++++++++++++ > fs/block_dev.c | 28 ++++++++++++++++++++++++++++ > include/linux/blkdev.h | 3 +++ > include/linux/dax.h | 2 ++ > 5 files changed, 67 insertions(+) > > diff --git a/block/Kconfig b/block/Kconfig > index 8bf114a3858a..9be785173280 100644 > --- a/block/Kconfig > +++ b/block/Kconfig > @@ -6,6 +6,7 @@ menuconfig BLOCK > default y > select SBITMAP > select SRCU > + select DAX > help > Provide block layer support for the kernel. > > diff --git a/drivers/dax/super.c b/drivers/dax/super.c > index eb844ffea3cf..ab5b082df5dd 100644 > --- a/drivers/dax/super.c > +++ b/drivers/dax/super.c > @@ -65,6 +65,39 @@ struct dax_inode { > const struct dax_operations *ops; > }; > > +long dax_direct_access(struct dax_inode *dax_inode, phys_addr_t dev_addr, > + void **kaddr, pfn_t *pfn, long size) > +{ > + long avail; > + > + /* > + * The device driver is allowed to sleep, in order to make the > + * memory directly accessible. > + */ > + might_sleep(); > + > + if (!dax_inode) > + return -EOPNOTSUPP; > + > + if (!dax_inode_alive(dax_inode)) > + return -ENXIO; > + > + if (size < 0) > + return size; > + > + if (dev_addr % PAGE_SIZE) > + return -EINVAL; > + > + avail = dax_inode->ops->direct_access(dax_inode, dev_addr, kaddr, pfn, > + size); > + if (!avail) > + return -ERANGE; > + if (avail > 0 && avail & ~PAGE_MASK) > + return -ENXIO; > + return min(avail, size); > +} > +EXPORT_SYMBOL_GPL(dax_direct_access); > + > bool dax_inode_alive(struct dax_inode *dax_inode) > { > lockdep_assert_held(&dax_srcu); > diff --git a/fs/block_dev.c b/fs/block_dev.c > index edb1d2b16b8f..bf4b51a3a412 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -18,6 +18,7 @@ > #include <linux/module.h> > #include <linux/blkpg.h> > #include <linux/magic.h> > +#include <linux/dax.h> > #include <linux/buffer_head.h> > #include <linux/swap.h> > #include <linux/pagevec.h> > @@ -763,6 +764,33 @@ long bdev_direct_access(struct block_device *bdev, > struct blk_dax_ctl *dax) > EXPORT_SYMBOL_GPL(bdev_direct_access); > > /** > + * bdev_dax_direct_access() - bdev-sector to pfn_t and kernel virtual address > + * @bdev: host block device for @dax_inode > + * @dax_inode: interface data and operations for a memory device > + * @dax: control and output parameters for ->direct_access > + * > + * Return: negative errno if an error occurs, otherwise the number of bytes > + * accessible at this address. > + * > + * Locking: must be called with dax_read_lock() held > + */ > +long bdev_dax_direct_access(struct block_device *bdev, > + struct dax_inode *dax_inode, struct blk_dax_ctl *dax) > +{ > + sector_t sector = dax->sector; > + > + if (!blk_queue_dax(bdev->bd_queue)) > + return -EOPNOTSUPP;
I don't think this should take a bdev - the caller should know if it has a dax_inode. Also if you touch this anyway can we kill the annoying struct blk_dax_ctl calling convention? Passing the four arguments explicitly is just a lot more readable and understandable. > + if ((sector + DIV_ROUND_UP(dax->size, 512)) > + > part_nr_sects_read(bdev->bd_part)) > + return -ERANGE; > + sector += get_start_sect(bdev); > + return dax_direct_access(dax_inode, sector * 512, &dax->addr, > + &dax->pfn, dax->size); And please switch to using bytes as the granularity given that we're deadling with byte addressable memory. _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
