On Mon 21-09-20 11:23:07, Naresh Kamboju wrote:
> On Fri, 18 Sep 2020 at 11:18, Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> >
> > From: Jan Kara <jack@xxxxxxx>
> >
> > DM was calling generic_fsdax_supported() to determine whether a device
> > referenced in the DM table supports DAX. However this is a helper for "leaf" device drivers so that
> > they don't have to duplicate common generic checks. High level code
> > should call dax_supported() helper which that calls into appropriate
> > helper for the particular device. This problem manifested itself as
> > kernel messages:
> >
> > dm-3: error: dax access failed (-95)
> >
> > when lvm2-testsuite run in cases where a DM device was stacked on top of
> > another DM device.
> >
> > Fixes: 7bf7eac8d648 ("dax: Arrange for dax_supported check to span multiple devices")
> > Cc: <stable@xxxxxxxxxxxxxxx>
> > Tested-by: Adrian Huang <ahuang12@xxxxxxxxxx>
> > Signed-off-by: Jan Kara <jack@xxxxxxx>
> > Acked-by: Mike Snitzer <snitzer@xxxxxxxxxx>
> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> > ---
> > Changes since v1 [1]:
> > - Add missing dax_read_lock() around dax_supported()
> >
> > [1]: http://lore.kernel.org/r/20200916151445.450-1-jack@xxxxxxx
> >
> > drivers/dax/super.c | 4 ++++
> > drivers/md/dm-table.c | 10 +++++++---
> > include/linux/dax.h | 11 +++++++++--
> > 3 files changed, 20 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> > index e5767c83ea23..b6284c5cae0a 100644
> > --- a/drivers/dax/super.c
> > +++ b/drivers/dax/super.c
> > @@ -325,11 +325,15 @@ EXPORT_SYMBOL_GPL(dax_direct_access);
> > bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
> > int blocksize, sector_t start, sector_t len)
> > {
> > + if (!dax_dev)
> > + return false;
> > +
> > if (!dax_alive(dax_dev))
> > return false;
> >
> > return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);
> > }
> > +EXPORT_SYMBOL_GPL(dax_supported);
>
> arm build error while building with allmodconfig.
>
> ../drivers/dax/super.c:325:6: error: redefinition of ‘dax_supported’
> 325 | bool dax_supported(struct dax_device *dax_dev, struct
> block_device *bdev,
> | ^~~~~~~~~~~~~
> In file included from ../drivers/dax/super.c:16:
> ../include/linux/dax.h:162:20: note: previous definition of
> ‘dax_supported’ was here
> 162 | static inline bool dax_supported(struct dax_device *dax_dev,
> | ^~~~~~~~~~~~~
> make[3]: *** [../scripts/Makefile.build:283: drivers/dax/super.o] Error 1
>
> Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
>
> Ref:
> https://builds.tuxbuild.com/IO690jFQDp0qP9zFuWBqpA/build.log
Thanks for report! Attached patch should fix the build (at least I've
tested it with CONFIG_DAX && CONFIG_FS_DAX, CONFIG_DAX && !CONFIG_FS_DAX,
and !CONFIG_DAX cases). Dan can you please merge the fix?
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
>From c48c9d1ee41ca17561dfd7ec5247b5afc527d40e Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@xxxxxxx>
Date: Mon, 21 Sep 2020 11:33:23 +0200
Subject: [PATCH] dax: Fix compilation for CONFIG_DAX && !CONFIG_FS_DAX
dax_supported() is defined whenever CONFIG_DAX is enabled. So dummy
implementation should be defined only in !CONFIG_DAX case, not in
!CONFIG_FS_DAX case.
Fixes: e2ec51282545 ("dm: Call proper helper to determine dax support")
Cc: <stable@xxxxxxxxxxxxxxx>
Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
include/linux/dax.h | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 497031392e0a..43b39ab9de1a 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -58,6 +58,8 @@ static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
__set_dax_synchronous(dax_dev);
}
+bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
+ int blocksize, sector_t start, sector_t len);
/*
* Check if given mapping is supported by the file / underlying device.
*/
@@ -104,6 +106,12 @@ static inline bool dax_synchronous(struct dax_device *dax_dev)
static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
}
+static inline bool dax_supported(struct dax_device *dax_dev,
+ struct block_device *bdev, int blocksize, sector_t start,
+ sector_t len)
+{
+ return false;
+}
static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
struct dax_device *dax_dev)
{
@@ -130,8 +138,6 @@ static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
sectors);
}
-bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
- int blocksize, sector_t start, sector_t len);
static inline void fs_put_dax(struct dax_device *dax_dev)
{
@@ -159,13 +165,6 @@ static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
return false;
}
-static inline bool dax_supported(struct dax_device *dax_dev,
- struct block_device *bdev, int blocksize, sector_t start,
- sector_t len)
-{
- return false;
-}
-
static inline void fs_put_dax(struct dax_device *dax_dev)
{
}
--
2.16.4
