[PATCH v1] io-mapping: Indicate mapping failure

[Michael J. Ruhl]

The !ATOMIC_IOMAP version of io_maping_init_wc will always return
success, even when the ioremap fails.

Since the ATOMIC_IOMAP version returns NULL when the init fails, and
callers check for a NULL return on error this is unexpected.

Return NULL on ioremap failure.

Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata about the io-mapping"
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Mike Rapoport <rppt at linux.ibm.com>
Cc: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: stable at vger.kernel.org
Signed-off-by: Michael J. Ruhl <michael.j.ruhl at intel.com>
---
 include/linux/io-mapping.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
index 0beaa3eba155..5641e06cbcf7 100644
--- a/include/linux/io-mapping.h
+++ b/include/linux/io-mapping.h
@@ -118,7 +118,7 @@ io_mapping_init_wc(struct io_mapping *iomap,
 	iomap->prot = pgprot_noncached(PAGE_KERNEL);
 #endif
 
-	return iomap;
+	return iomap->iomem ? iomap : NULL;
 }
 
 static inline void
-- 
2.21.0