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Revert "block: enable dax for raw block devices"

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This reverts commit 5a023cdba5.

The functionality is superseded by the new "Device DAX" facility.

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams
2016-05-07 11:40:28 -07:00
parent dee4107924
commit acc93d30d7
4 changed files with 29 additions and 108 deletions
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96
fs/block_dev.c
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@@ -29,6 +29,7 @@
#include <linux/log2.h>
#include <linux/cleancache.h>
#include <linux/dax.h>
#include <linux/badblocks.h>
#include <asm/uaccess.h>
#include "internal.h"
@@ -1159,6 +1160,33 @@ void bd_set_size(struct block_device *bdev, loff_t size)
}
EXPORT_SYMBOL(bd_set_size);
static bool blkdev_dax_capable(struct block_device *bdev)
{
struct gendisk *disk = bdev->bd_disk;
if (!disk->fops->direct_access || !IS_ENABLED(CONFIG_FS_DAX))
return false;
/*
* If the partition is not aligned on a page boundary, we can't
* do dax I/O to it.
*/
if ((bdev->bd_part->start_sect % (PAGE_SIZE / 512))
|| (bdev->bd_part->nr_sects % (PAGE_SIZE / 512)))
return false;
/*
* If the device has known bad blocks, force all I/O through the
* driver / page cache.
*
* TODO: support finer grained dax error handling
*/
if (disk->bb && disk->bb->count)
return false;
return true;
}
static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
/*
@@ -1724,79 +1752,13 @@ static const struct address_space_operations def_blk_aops = {
.is_dirty_writeback = buffer_check_dirty_writeback,
};
#ifdef CONFIG_FS_DAX
/*
* In the raw block case we do not need to contend with truncation nor
* unwritten file extents. Without those concerns there is no need for
* additional locking beyond the mmap_sem context that these routines
* are already executing under.
*
* Note, there is no protection if the block device is dynamically
* resized (partition grow/shrink) during a fault. A stable block device
* size is already not enforced in the blkdev_direct_IO path.
*
* For DAX, it is the responsibility of the block device driver to
* ensure the whole-disk device size is stable while requests are in
* flight.
*
* Finally, unlike the filemap_page_mkwrite() case there is no
* filesystem superblock to sync against freezing. We still include a
* pfn_mkwrite callback for dax drivers to receive write fault
* notifications.
*/
static int blkdev_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
return __dax_fault(vma, vmf, blkdev_get_block, NULL);
}
static int blkdev_dax_pfn_mkwrite(struct vm_area_struct *vma,
struct vm_fault *vmf)
{
return dax_pfn_mkwrite(vma, vmf);
}
static int blkdev_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd, unsigned int flags)
{
return __dax_pmd_fault(vma, addr, pmd, flags, blkdev_get_block, NULL);
}
static const struct vm_operations_struct blkdev_dax_vm_ops = {
.fault = blkdev_dax_fault,
.pmd_fault = blkdev_dax_pmd_fault,
.pfn_mkwrite = blkdev_dax_pfn_mkwrite,
};
static const struct vm_operations_struct blkdev_default_vm_ops = {
.fault = filemap_fault,
.map_pages = filemap_map_pages,
};
static int blkdev_mmap(struct file *file, struct vm_area_struct *vma)
{
struct inode *bd_inode = bdev_file_inode(file);
file_accessed(file);
if (IS_DAX(bd_inode)) {
vma->vm_ops = &blkdev_dax_vm_ops;
vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
} else {
vma->vm_ops = &blkdev_default_vm_ops;
}
return 0;
}
#else
#define blkdev_mmap generic_file_mmap
#endif
const struct file_operations def_blk_fops = {
.open = blkdev_open,
.release = blkdev_close,
.llseek = block_llseek,
.read_iter = blkdev_read_iter,
.write_iter = blkdev_write_iter,
.mmap = blkdev_mmap,
.mmap = generic_file_mmap,
.fsync = blkdev_fsync,
.unlocked_ioctl = block_ioctl,
#ifdef CONFIG_COMPAT