* [ndctl PATCH] libndctl/papr: Fix probe for papr-scm compatible nvdimms
@ 2021-05-17 15:48 Vaibhav Jain
0 siblings, 0 replies; only message in thread
From: Vaibhav Jain @ 2021-05-17 15:48 UTC (permalink / raw)
To: linux-nvdimm, nvdimm; +Cc: Vaibhav Jain, Aneesh Kumar K . V
With recent changes introduced for unification of PAPR and NFIT
families the probe for papr-scm nvdimms is broken since they don't
expose 'handle' or 'phys_id' sysfs attributes. These attributes are
only exposed by NFIT and 'nvdimm_test' nvdimms. Since 'unable to read'
these sysfs attributes is a non-recoverable error hence this prevents
probing of 'PAPR-SCM' nvdimms and ndctl reports following error:
$ sudo NDCTL_LOG=debug ndctl list -DH
libndctl: ndctl_new: ctx 0x10015342c70 created
libndctl: add_dimm: nmem1: probe failed: Operation not permitted
libndctl: __sysfs_device_parse: nmem1: add_dev() failed
libndctl: add_dimm: nmem0: probe failed: Operation not permitted
libndctl: __sysfs_device_parse: nmem0: add_dev() failed
Fixing this bug is complicated by the fact these attributes are needed
for by the 'nvdimm_test' nvdimms which also uses the
NVDIMM_FAMILY_PAPR. Adding a two way comparison for these two
attributes in populate_dimm_attributes() to distinguish between
'nvdimm_test' and papr-scm nvdimms will be clunky and make future
updates to populate_dimm_attributes() error prone.
So, this patch proposes to fix the issue by re-introducing
add_papr_dimm() to probe both papr-scm and 'nvdimm_test' nvdimms. The
'compatible' sysfs attribute associated with the PAPR device is used
to distinguish between the two nvdimm types and in case an
'nvdimm_test' device is detected then forward its probe to
populate_dimm_attributes().
Fixes: daef3a386a9c("libndctl: Unify adding dimms for papr and nfit
families")
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
ndctl/lib/libndctl.c | 57 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 55 insertions(+), 2 deletions(-)
diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c
index bf0968cce93f..0417720ccd7e 100644
--- a/ndctl/lib/libndctl.c
+++ b/ndctl/lib/libndctl.c
@@ -1757,6 +1757,58 @@ static int populate_dimm_attributes(struct ndctl_dimm *dimm,
return rc;
}
+static int add_papr_dimm(struct ndctl_dimm *dimm, const char *dimm_base)
+{
+ int rc = -ENODEV;
+ char buf[SYSFS_ATTR_SIZE];
+ struct ndctl_ctx *ctx = dimm->bus->ctx;
+ char *path = calloc(1, strlen(dimm_base) + 100);
+ const char * const devname = ndctl_dimm_get_devname(dimm);
+
+ dbg(ctx, "%s: Probing of_pmem dimm at %s\n", devname, dimm_base);
+
+ if (!path)
+ return -ENOMEM;
+
+ /* Check the compatibility of the probed nvdimm */
+ sprintf(path, "%s/../of_node/compatible", dimm_base);
+ if (sysfs_read_attr(ctx, path, buf) < 0) {
+ dbg(ctx, "%s: Unable to read compatible field\n", devname);
+ rc = -ENODEV;
+ goto out;
+ }
+
+ dbg(ctx, "%s:Compatible of_pmem = '%s'\n", devname, buf);
+
+ /* Probe for papr-scm memory */
+ if (strcmp(buf, "ibm,pmemory") == 0) {
+ /* Read the dimm flags file */
+ sprintf(path, "%s/papr/flags", dimm_base);
+ if (sysfs_read_attr(ctx, path, buf) < 0) {
+ rc = -errno;
+ err(ctx, "%s: Unable to read dimm-flags\n", devname);
+ goto out;
+ }
+
+ dbg(ctx, "%s: Adding papr-scm dimm flags:\"%s\"\n", devname, buf);
+ dimm->cmd_family = NVDIMM_FAMILY_PAPR;
+
+ /* Parse dimm flags */
+ parse_papr_flags(dimm, buf);
+
+ /* Allocate monitor mode fd */
+ dimm->health_eventfd = open(path, O_RDONLY|O_CLOEXEC);
+ rc = 0;
+
+ } else if (strcmp(buf, "nvdimm_test") == 0) {
+ /* probe via common populate_dimm_attributes() */
+ rc = populate_dimm_attributes(dimm, dimm_base, "papr");
+ }
+out:
+ free(path);
+ return rc;
+}
+
static void *add_dimm(void *parent, int id, const char *dimm_base)
{
int formats, i, rc = -ENODEV;
@@ -1848,8 +1900,9 @@ static void *add_dimm(void *parent, int id, const char *dimm_base)
/* Check if the given dimm supports nfit */
if (ndctl_bus_has_nfit(bus)) {
rc = populate_dimm_attributes(dimm, dimm_base, "nfit");
- } else if (ndctl_bus_has_of_node(bus))
- rc = populate_dimm_attributes(dimm, dimm_base, "papr");
+ } else if (ndctl_bus_has_of_node(bus)) {
+ rc = add_papr_dimm(dimm, dimm_base);
+ }
if (rc == -ENODEV) {
/* Unprobed dimm with no family */
--
2.31.1
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