Commit 6d439c18 authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Andrew Morton
Browse files

dax: alloc_dax() return ERR_PTR(-EOPNOTSUPP) for CONFIG_DAX=n 

Change the return value from NULL to PTR_ERR(-EOPNOTSUPP) for
CONFIG_DAX=n to be consistent with the fact that CONFIG_DAX=y
never returns NULL.

This is done in preparation for using cpu_dcache_is_aliasing() in a
following change which will properly support architectures which detect
data cache aliasing at runtime.

Link: https://lkml.kernel.org/r/20240215144633.96437-3-mathieu.desnoyers@efficios.com


Fixes: 4e4ced93 ("dax: Move mandatory ->zero_page_range() check in alloc_dax()")
Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Michael Sclafani <dm-devel@lists.linux.dev>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 2807c54b

drivers/dax/super.c

+5 −0
Original line number Diff line number Diff line
@@ -319,6 +319,11 @@ EXPORT_SYMBOL_GPL(dax_alive); 
 * that any fault handlers or operations that might have seen

 * dax_alive(), have completed.  Any operations that start after

 * synchronize_srcu() has run will abort upon seeing !dax_alive().

 *

 * Note, because alloc_dax() returns an ERR_PTR() on error, callers

 * typically store its result into a local variable in order to check

 * the result. Therefore, care must be taken to populate the struct

 * device dax_dev field make sure the dax_dev is not leaked.

 */

void kill_dax(struct dax_device *dax_dev)

{

include/linux/dax.h

+1 −5
Original line number Diff line number Diff line
@@ -88,11 +88,7 @@ static inline void *dax_holder(struct dax_device *dax_dev) 
static inline struct dax_device *alloc_dax(void *private,

		const struct dax_operations *ops)

{

	/*

	 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this

	 * NULL is an error or expected.

	 */

	return NULL;

	return ERR_PTR(-EOPNOTSUPP);

}

static inline void put_dax(struct dax_device *dax_dev)

{