block: Add support for DAX reads/writes to block devices

If a block device supports the ->direct_access methods, bypass the normal
DIO path and use DAX to go straight to memcpy() instead of allocating
a DIO and a BIO.

Includes support for the DIO_SKIP_DIO_COUNT flag in DAX, as is done in
do_blockdev_direct_IO().

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Matthew Wilcox 2015-07-03 10:40:42 -04:00 committed by Al Viro
parent 872eb127e3
commit bbab37ddc2
2 changed files with 8 additions and 2 deletions

View file

@ -209,7 +209,8 @@ ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode,
}
/* Protects against truncate */
inode_dio_begin(inode);
if (!(flags & DIO_SKIP_DIO_COUNT))
inode_dio_begin(inode);
retval = dax_io(inode, iter, pos, end, get_block, &bh);
@ -219,7 +220,8 @@ ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode,
if ((retval > 0) && end_io)
end_io(iocb, pos, retval, bh.b_private);
inode_dio_end(inode);
if (!(flags & DIO_SKIP_DIO_COUNT))
inode_dio_end(inode);
out:
return retval;
}