nvdimm.lists.linux.dev archive mirror
 help / color / mirror / Atom feed
From: Vaibhav Jain <vaibhav@linux.ibm.com>
To: linux-nvdimm@lists.01.org
Cc: Vaibhav Jain <vaibhav@linux.ibm.com>,
	"Aneesh Kumar K . V Ira Weiny"
	<"aneesh.kumar@linux.ibm.comira.weiny"@intel.com>,
	mpe@ellerman.id.au, Shivaprasad G Bhat <sbhat@linux.ibm.com>
Subject: [PATCH] libnvdimm/region: Update nvdimm_has_flush() to handle ND_REGION_ASYNC
Date: Fri,  2 Apr 2021 14:55:55 +0530	[thread overview]
Message-ID: <20210402092555.208590-1-vaibhav@linux.ibm.com> (raw)

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
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

             reply	other threads:[~2021-04-02  9:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-02  9:25 Vaibhav Jain [this message]
2021-04-05 11:31 ` Aneesh Kumar K.V
2021-04-10  4:51   ` Dan Williams
2021-04-10  4:46 ` Dan Williams

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210402092555.208590-1-vaibhav@linux.ibm.com \
    --to=vaibhav@linux.ibm.com \
    --cc="aneesh.kumar@linux.ibm.comira.weiny"@intel.com \
    --cc=linux-nvdimm@lists.01.org \
    --cc=mpe@ellerman.id.au \
    --cc=sbhat@linux.ibm.com \
    --subject='Re: [PATCH] libnvdimm/region: Update nvdimm_has_flush() to handle ND_REGION_ASYNC' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).