* [PATCH] libnvdimm/region: Update nvdimm_has_flush() to handle ND_REGION_ASYNC
@ 2021-04-02 9:25 Vaibhav Jain
2021-04-05 11:31 ` Aneesh Kumar K.V
2021-04-10 4:46 ` Dan Williams
0 siblings, 2 replies; 4+ messages in thread
From: Vaibhav Jain @ 2021-04-02 9:25 UTC (permalink / raw)
To: linux-nvdimm
Cc: Vaibhav Jain, Aneesh Kumar K . V Ira Weiny, mpe, Shivaprasad G Bhat
In case a platform doesn't provide explicit flush-hints but provides an
explicit flush callback via ND_REGION_ASYNC region flag, then
nvdimm_has_flush() still returns '0' indicating that writes do not
require flushing. This happens on PPC64 with patch at [1] applied,
where 'deep_flush' of a region was denied even though an explicit
flush function was provided.
Fix this by adding a condition to nvdimm_has_flush() to test for the
ND_REGION_ASYNC flag on the region and see if a 'region->flush'
callback is assigned.
References:
[1] "powerpc/papr_scm: Implement support for H_SCM_FLUSH hcall"
https://lore.kernel.org/linux-nvdimm/161703936121.36.7260632399 582101498.stgit@e1fbed493c87
Reported-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
drivers/nvdimm/region_devs.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index ef23119db574..e05cc9f8a9fd 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -1239,6 +1239,11 @@ int nvdimm_has_flush(struct nd_region *nd_region)
|| !IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API))
return -ENXIO;
+ /* Test if an explicit flush function is defined */
+ if (test_bit(ND_REGION_ASYNC, &nd_region->flags) && nd_region->flush)
+ return 1;
+
+ /* Test if any flush hints for the region are available */
for (i = 0; i < nd_region->ndr_mappings; i++) {
struct nd_mapping *nd_mapping = &nd_region->mapping[i];
struct nvdimm *nvdimm = nd_mapping->nvdimm;
@@ -1249,8 +1254,8 @@ int nvdimm_has_flush(struct nd_region *nd_region)
}
/*
- * The platform defines dimm devices without hints, assume
- * platform persistence mechanism like ADR
+ * The platform defines dimm devices without hints nor explicit flush,
+ * assume platform persistence mechanism like ADR
*/
return 0;
}
--
2.30.2
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^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] libnvdimm/region: Update nvdimm_has_flush() to handle ND_REGION_ASYNC
2021-04-02 9:25 [PATCH] libnvdimm/region: Update nvdimm_has_flush() to handle ND_REGION_ASYNC Vaibhav Jain
@ 2021-04-05 11:31 ` Aneesh Kumar K.V
2021-04-10 4:51 ` Dan Williams
2021-04-10 4:46 ` Dan Williams
1 sibling, 1 reply; 4+ messages in thread
From: Aneesh Kumar K.V @ 2021-04-05 11:31 UTC (permalink / raw)
To: Vaibhav Jain, linux-nvdimm, Dan Williams
Cc: Vaibhav Jain, mpe, Shivaprasad G Bhat
Vaibhav Jain <vaibhav@linux.ibm.com> writes:
> In case a platform doesn't provide explicit flush-hints but provides an
> explicit flush callback via ND_REGION_ASYNC region flag, then
> nvdimm_has_flush() still returns '0' indicating that writes do not
> require flushing. This happens on PPC64 with patch at [1] applied,
> where 'deep_flush' of a region was denied even though an explicit
> flush function was provided.
>
> Fix this by adding a condition to nvdimm_has_flush() to test for the
> ND_REGION_ASYNC flag on the region and see if a 'region->flush'
> callback is assigned.
>
May be this should have
Fixes: c5d4355d10d4 ("libnvdimm: nd_region flush callback support")
Without this we will mark the pmem disk not having FUA support?
> References:
> [1] "powerpc/papr_scm: Implement support for H_SCM_FLUSH hcall"
> https://lore.kernel.org/linux-nvdimm/161703936121.36.7260632399 582101498.stgit@e1fbed493c87
>
> Reported-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
> ---
> drivers/nvdimm/region_devs.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
> index ef23119db574..e05cc9f8a9fd 100644
> --- a/drivers/nvdimm/region_devs.c
> +++ b/drivers/nvdimm/region_devs.c
> @@ -1239,6 +1239,11 @@ int nvdimm_has_flush(struct nd_region *nd_region)
> || !IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API))
> return -ENXIO;
>
> + /* Test if an explicit flush function is defined */
> + if (test_bit(ND_REGION_ASYNC, &nd_region->flags) && nd_region->flush)
> + return 1;
> +
> + /* Test if any flush hints for the region are available */
> for (i = 0; i < nd_region->ndr_mappings; i++) {
> struct nd_mapping *nd_mapping = &nd_region->mapping[i];
> struct nvdimm *nvdimm = nd_mapping->nvdimm;
> @@ -1249,8 +1254,8 @@ int nvdimm_has_flush(struct nd_region *nd_region)
> }
>
> /*
> - * The platform defines dimm devices without hints, assume
> - * platform persistence mechanism like ADR
> + * The platform defines dimm devices without hints nor explicit flush,
> + * assume platform persistence mechanism like ADR
> */
> return 0;
> }
> --
> 2.30.2
> _______________________________________________
> Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
> To unsubscribe send an email to linux-nvdimm-leave@lists.01.org
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] libnvdimm/region: Update nvdimm_has_flush() to handle ND_REGION_ASYNC
2021-04-05 11:31 ` Aneesh Kumar K.V
@ 2021-04-10 4:51 ` Dan Williams
0 siblings, 0 replies; 4+ messages in thread
From: Dan Williams @ 2021-04-10 4:51 UTC (permalink / raw)
To: Aneesh Kumar K.V
Cc: Vaibhav Jain, linux-nvdimm, Michael Ellerman, Shivaprasad G Bhat
On Mon, Apr 5, 2021 at 4:31 AM Aneesh Kumar K.V
<aneesh.kumar@linux.ibm.com> wrote:
>
> Vaibhav Jain <vaibhav@linux.ibm.com> writes:
>
> > In case a platform doesn't provide explicit flush-hints but provides an
> > explicit flush callback via ND_REGION_ASYNC region flag, then
> > nvdimm_has_flush() still returns '0' indicating that writes do not
> > require flushing. This happens on PPC64 with patch at [1] applied,
> > where 'deep_flush' of a region was denied even though an explicit
> > flush function was provided.
> >
> > Fix this by adding a condition to nvdimm_has_flush() to test for the
> > ND_REGION_ASYNC flag on the region and see if a 'region->flush'
> > callback is assigned.
> >
>
> May be this should have
> Fixes: c5d4355d10d4 ("libnvdimm: nd_region flush callback support")
Yes, thanks for that.
>
> Without this we will mark the pmem disk not having FUA support?
Yes.
>
>
> > References:
> > [1] "powerpc/papr_scm: Implement support for H_SCM_FLUSH hcall"
> > https://lore.kernel.org/linux-nvdimm/161703936121.36.7260632399 582101498.stgit@e1fbed493c87
> >
> > Reported-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
> > Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
> > ---
> > drivers/nvdimm/region_devs.c | 9 +++++++--
> > 1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
> > index ef23119db574..e05cc9f8a9fd 100644
> > --- a/drivers/nvdimm/region_devs.c
> > +++ b/drivers/nvdimm/region_devs.c
> > @@ -1239,6 +1239,11 @@ int nvdimm_has_flush(struct nd_region *nd_region)
> > || !IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API))
> > return -ENXIO;
> >
> > + /* Test if an explicit flush function is defined */
> > + if (test_bit(ND_REGION_ASYNC, &nd_region->flags) && nd_region->flush)
> > + return 1;
>
> > +
> > + /* Test if any flush hints for the region are available */
> > for (i = 0; i < nd_region->ndr_mappings; i++) {
> > struct nd_mapping *nd_mapping = &nd_region->mapping[i];
> > struct nvdimm *nvdimm = nd_mapping->nvdimm;
> > @@ -1249,8 +1254,8 @@ int nvdimm_has_flush(struct nd_region *nd_region)
> > }
> >
> > /*
> > - * The platform defines dimm devices without hints, assume
> > - * platform persistence mechanism like ADR
> > + * The platform defines dimm devices without hints nor explicit flush,
> > + * assume platform persistence mechanism like ADR
> > */
> > return 0;
> > }
> > --
> > 2.30.2
> > _______________________________________________
> > Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
> > To unsubscribe send an email to linux-nvdimm-leave@lists.01.org
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] libnvdimm/region: Update nvdimm_has_flush() to handle ND_REGION_ASYNC
2021-04-02 9:25 [PATCH] libnvdimm/region: Update nvdimm_has_flush() to handle ND_REGION_ASYNC Vaibhav Jain
2021-04-05 11:31 ` Aneesh Kumar K.V
@ 2021-04-10 4:46 ` Dan Williams
1 sibling, 0 replies; 4+ messages in thread
From: Dan Williams @ 2021-04-10 4:46 UTC (permalink / raw)
To: Vaibhav Jain
Cc: linux-nvdimm, Aneesh Kumar K, Michael Ellerman, Shivaprasad G Bhat
On Fri, Apr 2, 2021 at 2:26 AM Vaibhav Jain <vaibhav@linux.ibm.com> wrote:
>
> In case a platform doesn't provide explicit flush-hints but provides an
> explicit flush callback via ND_REGION_ASYNC region flag, then
> nvdimm_has_flush() still returns '0' indicating that writes do not
> require flushing. This happens on PPC64 with patch at [1] applied,
> where 'deep_flush' of a region was denied even though an explicit
> flush function was provided.
>
> Fix this by adding a condition to nvdimm_has_flush() to test for the
> ND_REGION_ASYNC flag on the region and see if a 'region->flush'
> callback is assigned.
Looks good.
>
> References:
> [1] "powerpc/papr_scm: Implement support for H_SCM_FLUSH hcall"
> https://lore.kernel.org/linux-nvdimm/161703936121.36.7260632399 582101498.stgit@e1fbed493c87
Looks like a typo happened in that link, I can fix that up. I'll also
change this to the canonical "Link:" tag for references.
>
> Reported-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
> ---
> drivers/nvdimm/region_devs.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
> index ef23119db574..e05cc9f8a9fd 100644
> --- a/drivers/nvdimm/region_devs.c
> +++ b/drivers/nvdimm/region_devs.c
> @@ -1239,6 +1239,11 @@ int nvdimm_has_flush(struct nd_region *nd_region)
> || !IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API))
> return -ENXIO;
>
> + /* Test if an explicit flush function is defined */
> + if (test_bit(ND_REGION_ASYNC, &nd_region->flags) && nd_region->flush)
> + return 1;
> +
> + /* Test if any flush hints for the region are available */
> for (i = 0; i < nd_region->ndr_mappings; i++) {
> struct nd_mapping *nd_mapping = &nd_region->mapping[i];
> struct nvdimm *nvdimm = nd_mapping->nvdimm;
> @@ -1249,8 +1254,8 @@ int nvdimm_has_flush(struct nd_region *nd_region)
> }
>
> /*
> - * The platform defines dimm devices without hints, assume
> - * platform persistence mechanism like ADR
> + * The platform defines dimm devices without hints nor explicit flush,
> + * assume platform persistence mechanism like ADR
> */
> return 0;
> }
> --
> 2.30.2
>
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2021-04-02 9:25 [PATCH] libnvdimm/region: Update nvdimm_has_flush() to handle ND_REGION_ASYNC Vaibhav Jain
2021-04-05 11:31 ` Aneesh Kumar K.V
2021-04-10 4:51 ` Dan Williams
2021-04-10 4:46 ` Dan Williams
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