> -----Original Message-----
> From: Coly Li <colyli@xxxxxxx>
> Sent: Thursday, September 3, 2020 7:56 PM
> To: linux-nvdimm@xxxxxxxxxxxx
> Cc: dm-devel@xxxxxxxxxx; Coly Li <colyli@xxxxxxx>; Adrian Huang12
> <ahuang12@xxxxxxxxxx>; Ira Weiny <ira.weiny@xxxxxxxxx>; Jan Kara
> <jack@xxxxxxxx>; Mike Snitzer <snitzer@xxxxxxxxxx>; Pankaj Gupta
> <pankaj.gupta.linux@xxxxxxxxx>; Vishal Verma <vishal.l.verma@xxxxxxxxx>
> Subject: [External] [PATCH] dax: fix for do not print error message for non-
> persistent memory block device
>
> When calling __generic_fsdax_supported(), a dax-unsupported device may not
> have dax_dev as NULL, e.g. the dax related code block is not enabled by Kconfig.
>
> Therefore in __generic_fsdax_supported(), to check whether a device supports
> DAX or not, the following order should be performed,
> - If dax_dev pointer is NULL, it means the device driver explicitly
> announce it doesn't support DAX. Then it is OK to directly return
> false from __generic_fsdax_supported().
> - If dax_dev pointer is NOT NULL, it might be because the driver doesn't
> support DAX and not explicitly initialize related data structure. Then
> bdev_dax_supported() should be called for further check.
>
> IMHO if device driver desn't explicitly set its dax_dev pointer to NULL, this is not
> a bug. Calling bdev_dax_supported() makes sure they can be recognized as dax-
> unsupported eventually.
>
> This patch does the following change for the above purpose,
> - if (!dax_dev && !bdev_dax_supported(bdev, blocksize)) {
> + if (!dax_dev || !bdev_dax_supported(bdev, blocksize)) {
>
>
> Fixes: c2affe920b0e ("dax: do not print error message for non-persistent
> memory block device")
> Signed-off-by: Coly Li <colyli@xxxxxxx>
The dax error messages ("dm-X: error: dax access failed (-95)") are gone away when executing the command 'lvm2-testsuite --only activate-minor'.
Reviewed-and-Tested-by: Adrian Huang <ahuang12@xxxxxxxxxx>
> Cc: Adrian Huang <ahuang12@xxxxxxxxxx>
> Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
> Cc: Jan Kara <jack@xxxxxxxx>
> Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
> Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
> Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
> ---
> drivers/dax/super.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dax/super.c b/drivers/dax/super.c index
> 32642634c1bb..e5767c83ea23 100644
> --- a/drivers/dax/super.c
> +++ b/drivers/dax/super.c
> @@ -100,7 +100,7 @@ bool __generic_fsdax_supported(struct dax_device
> *dax_dev,
> return false;
> }
>
> - if (!dax_dev && !bdev_dax_supported(bdev, blocksize)) {
> + if (!dax_dev || !bdev_dax_supported(bdev, blocksize)) {
> pr_debug("%s: error: dax unsupported by block device\n",
> bdevname(bdev, buf));
> return false;
> --
> 2.26.2
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