dax: enable dax in the presence of known media errors (badblocks)

1/ If a mapping overlaps a bad sector fail the request.

2/ Do not opportunistically report more dax-capable capacity than is
   requested when errors present.

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
[vishal: fix a conflict with system RAM collision patches]
[vishal: add a 'size' parameter to ->direct_access]
[vishal: fix a conflict with DAX alignment check patches]
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>

1 files changed, 1 insertions, 12 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 8477d4501b1e..45839b27972c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -29,7 +29,6 @@
 #include <linux/log2.h>
 #include <linux/cleancache.h>
 #include <linux/dax.h>
-#include <linux/badblocks.h>
 #include <asm/uaccess.h>
 #include "internal.h"
 
@@ -501,7 +500,7 @@ long bdev_direct_access(struct block_device *bdev, struct blk_dax_ctl *dax)
         sector += get_start_sect(bdev);
         if (sector % (PAGE_SIZE / 512))
                 return -EINVAL;
-        avail = ops->direct_access(bdev, sector, &dax->addr, &dax->pfn);
+        avail = ops->direct_access(bdev, sector, &dax->addr, &dax->pfn, size);
         if (!avail)
                 return -ERANGE;
         if (avail > 0 && avail & ~PAGE_MASK)
@@ -561,7 +560,6 @@ EXPORT_SYMBOL_GPL(bdev_dax_supported);
  */
 bool bdev_dax_capable(struct block_device *bdev)
 {
-        struct gendisk *disk = bdev->bd_disk;
         struct blk_dax_ctl dax = {
                 .size = PAGE_SIZE,
         };
@@ -577,15 +575,6 @@ bool bdev_dax_capable(struct block_device *bdev)
         if (bdev_direct_access(bdev, &dax) < 0)
                 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;
 }