pmem, dax: disable dax in the presence of bad blocks

Longer term teach dax to punch "error" holes in mapping requests and
deliver SIGBUS to applications that consume a bad pmem page.  For now,
simply disable the dax performance optimization in the presence of known
errors.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

2 files changed, 11 insertions, 0 deletions

diff --git a/block/ioctl.c b/block/ioctl.c
index 7a964d842913..2c84683aada5 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -4,6 +4,7 @@
 #include <linux/gfp.h>
 #include <linux/blkpg.h>
 #include <linux/hdreg.h>
+#include <linux/badblocks.h>
 #include <linux/backing-dev.h>
 #include <linux/fs.h>
 #include <linux/blktrace_api.h>
@@ -422,6 +423,15 @@ bool blkdev_dax_capable(struct block_device *bdev)
                         || (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;
 }
 
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index d00c659d1304..6a1832b3983c 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -233,6 +233,7 @@ static int pmem_attach_disk(struct device *dev,
                 return -ENOMEM;
         nvdimm_namespace_add_poison(ndns, &pmem->bb, pmem->data_offset);
 
+        disk->bb = &pmem->bb;
         add_disk(disk);
         revalidate_disk(disk);