- Some request-based DM core and DM multipath fixes and cleanups

- Constify a few variables in DM core and DM integrity
 
 - Add bufio optimization and checksum failure accounting to DM integrity
 
 - Fix DM integrity to avoid checking integrity of failed reads
 
 - Fix DM integrity to use init_completion
 
 - A couple DM log-writes target fixes
 
 - Simplify DAX flushing by eliminating the unnecessary flush abstraction
   that was stood up for DM's use.
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Merge tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Some request-based DM core and DM multipath fixes and cleanups

 - Constify a few variables in DM core and DM integrity

 - Add bufio optimization and checksum failure accounting to DM
   integrity

 - Fix DM integrity to avoid checking integrity of failed reads

 - Fix DM integrity to use init_completion

 - A couple DM log-writes target fixes

 - Simplify DAX flushing by eliminating the unnecessary flush
   abstraction that was stood up for DM's use.

* tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dax: remove the pmem_dax_ops->flush abstraction
  dm integrity: use init_completion instead of COMPLETION_INITIALIZER_ONSTACK
  dm integrity: make blk_integrity_profile structure const
  dm integrity: do not check integrity for failed read operations
  dm log writes: fix >512b sectorsize support
  dm log writes: don't use all the cpu while waiting to log blocks
  dm ioctl: constify ioctl lookup table
  dm: constify argument arrays
  dm integrity: count and display checksum failures
  dm integrity: optimize writing dm-bufio buffers that are partially changed
  dm rq: do not update rq partially in each ending bio
  dm rq: make dm-sq requeuing behavior consistent with dm-mq behavior
  dm mpath: complain about unsupported __multipath_map_bio() return values
  dm mpath: avoid that building with W=1 causes gcc 7 to complain about fall-through

drivers/dax/super.c

@@ -201,8 +201,10 @@ static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n)
 	if (!dax_dev)
 		return 0;
 
-	if (a == &dev_attr_write_cache.attr && !dax_dev->ops->flush)
+#ifndef CONFIG_ARCH_HAS_PMEM_API
+	if (a == &dev_attr_write_cache.attr)
 		return 0;
+#endif
 	return a->mode;
 }
 
@@ -267,18 +269,23 @@ size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 }
 EXPORT_SYMBOL_GPL(dax_copy_from_iter);
 
-void dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
-		size_t size)
+#ifdef CONFIG_ARCH_HAS_PMEM_API
+void arch_wb_cache_pmem(void *addr, size_t size);
+void dax_flush(struct dax_device *dax_dev, void *addr, size_t size)
 {
-	if (!dax_alive(dax_dev))
+	if (unlikely(!dax_alive(dax_dev)))
 		return;
 
-	if (!test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags))
+	if (unlikely(!test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags)))
 		return;
 
-	if (dax_dev->ops->flush)
-		dax_dev->ops->flush(dax_dev, pgoff, addr, size);
+	arch_wb_cache_pmem(addr, size);
 }
+#else
+void dax_flush(struct dax_device *dax_dev, void *addr, size_t size)
+{
+}
+#endif
 EXPORT_SYMBOL_GPL(dax_flush);
 
 void dax_write_cache(struct dax_device *dax_dev, bool wc)