[ndctl PATCH v4] libndctl: Update nvdimm flags in ndctl_cmd_submit()

[ndctl PATCH v4] libndctl: Update nvdimm flags in ndctl_cmd_submit()

[Vaibhav Jain]

Presently after performing an inject-smart the nvdimm flags reported are
out of date as shown below where no 'smart_notify' or 'flush_fail' flags
were reported even though they are set after injecting the smart error:

$ sudo inject-smart -fU nmem0
[
  {
    "dev":"nmem0",
    "health":{
      "health_state":"fatal",
      "shutdown_state":"dirty",
      "shutdown_count":0
    }
  }
]
$ sudo cat /sys/class/nd/ndctl0/device/nmem0/papr/flags
flush_fail smart_notify

This happens because nvdimm flags are only parsed once during its probe
and not refreshed even after a inject-smart operation makes them out of
date. To fix this the patch forces an update of nvdimm flags via newly
introduced ndctl_refresh_dimm_flags() thats called successfully submitting
a 'struct ndctl_cmd' in ndctl_cmd_submit(). This ensures that correct
nvdimm flags are reported after an interaction with the kernel module which
may trigger a change nvdimm-flags. With this implemented correct nvdimm
flags are reported after a inject-smart operation:

$ sudo ndctl inject-smart -fU nmem0
[
  {
    "dev":"nmem0",
    "flag_failed_flush":true,
    "flag_smart_event":true,
    "health":{
      "health_state":"fatal",
      "shutdown_state":"dirty",
      "shutdown_count":0
    }
  }
]

The patch refactors populate_dimm_attributes() to move the nvdimm flags
parsing code to the newly introduced ndctl_refresh_dimm_flags()
export. Since reading nvdimm flags requires constructing path using
'bus_prefix' which is only available during add_dimm(), the patch
introduces a new member 'struct ndctl_dimm.bus_prefix' to cache its
value. During ndctl_refresh_dimm_flags() the cached bus_prefix is used to
read the contents of the nvdimm flag file and pass it on to the appropriate
flag parsing function. Finally ndctl_refresh_dimm_flags() is invoked at the
end of ndctl_cmd_submit() if nd-command submission succeeds.

Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
---
Changelog:

Since v3-Resend:
164009789816.744139.2870779016511283907.stgit@lep8c.aus.stglabs.ibm.com
* Rebased this on top of latest ndctl-pending tree that includes changes to
switch to meson build system.
---
 ndctl/lib/libndctl.c | 52 ++++++++++++++++++++++++++++++++------------
 ndctl/lib/private.h  |  1 +
 ndctl/libndctl.h     |  1 +
 3 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c
index 5979a92c113c..abff4ececa27 100644
--- a/ndctl/lib/libndctl.c
+++ b/ndctl/lib/libndctl.c
@@ -608,6 +608,7 @@ static void free_dimm(struct ndctl_dimm *dimm)
 	free(dimm->unique_id);
 	free(dimm->dimm_buf);
 	free(dimm->dimm_path);
+	free(dimm->bus_prefix);
 	if (dimm->module)
 		kmod_module_unref(dimm->module);
 	if (dimm->health_eventfd > -1)
@@ -1670,14 +1671,34 @@ static int ndctl_bind(struct ndctl_ctx *ctx, struct kmod_module *module,
 static int ndctl_unbind(struct ndctl_ctx *ctx, const char *devpath);
 static struct kmod_module *to_module(struct ndctl_ctx *ctx, const char *alias);
 
+void ndctl_refresh_dimm_flags(struct ndctl_dimm *dimm)
+{
+	struct ndctl_ctx *ctx = dimm->bus->ctx;
+	char *path = dimm->dimm_buf;
+	char buf[SYSFS_ATTR_SIZE];
+
+	/* Construct path to dimm flags sysfs file */
+	sprintf(path, "%s/%s/flags", dimm->dimm_path, dimm->bus_prefix);
+
+	if (sysfs_read_attr(ctx, path, buf) < 0)
+		return;
+
+	/* Reset the flags */
+	dimm->flags.flags = 0;
+	if (ndctl_bus_has_nfit(dimm->bus))
+		parse_nfit_mem_flags(dimm, buf);
+	else if (ndctl_bus_is_papr_scm(dimm->bus))
+		parse_papr_flags(dimm, buf);
+}
+
 static int populate_dimm_attributes(struct ndctl_dimm *dimm,
-				    const char *dimm_base,
-				    const char *bus_prefix)
+				    const char *dimm_base)
 {
 	int i, rc = -1;
 	char buf[SYSFS_ATTR_SIZE];
 	struct ndctl_ctx *ctx = dimm->bus->ctx;
 	char *path = calloc(1, strlen(dimm_base) + 100);
+	const char *bus_prefix = dimm->bus_prefix;
 
 	if (!path)
 		return -ENOMEM;
@@ -1761,16 +1782,10 @@ static int populate_dimm_attributes(struct ndctl_dimm *dimm,
 	}
 
 	sprintf(path, "%s/%s/flags", dimm_base, bus_prefix);
-	if (sysfs_read_attr(ctx, path, buf) == 0) {
-		if (ndctl_bus_has_nfit(dimm->bus))
-			parse_nfit_mem_flags(dimm, buf);
-		else if (ndctl_bus_is_papr_scm(dimm->bus)) {
-			dimm->cmd_family = NVDIMM_FAMILY_PAPR;
-			parse_papr_flags(dimm, buf);
-		}
-	}
-
 	dimm->health_eventfd = open(path, O_RDONLY|O_CLOEXEC);
+
+	ndctl_refresh_dimm_flags(dimm);
+
 	rc = 0;
  err_read:
 
@@ -1826,8 +1841,9 @@ static int add_papr_dimm(struct ndctl_dimm *dimm, const char *dimm_base)
 
 		rc = 0;
 	} else if (strcmp(buf, "nvdimm_test") == 0) {
+		dimm->cmd_family = NVDIMM_FAMILY_PAPR;
 		/* probe via common populate_dimm_attributes() */
-		rc = populate_dimm_attributes(dimm, dimm_base, "papr");
+		rc = populate_dimm_attributes(dimm, dimm_base);
 	}
 out:
 	free(path);
@@ -1924,9 +1940,13 @@ static void *add_dimm(void *parent, int id, const char *dimm_base)
 	dimm->formats = formats;
 	/* Check if the given dimm supports nfit */
 	if (ndctl_bus_has_nfit(bus)) {
-		rc = populate_dimm_attributes(dimm, dimm_base, "nfit");
+		dimm->bus_prefix = strdup("nfit");
+		rc = dimm->bus_prefix ?
+			populate_dimm_attributes(dimm, dimm_base) : -ENOMEM;
 	} else if (ndctl_bus_has_of_node(bus)) {
-		rc = add_papr_dimm(dimm, dimm_base);
+		dimm->bus_prefix = strdup("papr");
+		rc = dimm->bus_prefix ?
+			add_papr_dimm(dimm, dimm_base) : -ENOMEM;
 	}
 
 	if (rc == -ENODEV) {
@@ -3506,6 +3526,10 @@ NDCTL_EXPORT int ndctl_cmd_submit(struct ndctl_cmd *cmd)
 		rc = -ENXIO;
 	}
 	close(fd);
+
+	/* update dimm-flags if command submitted successfully */
+	if (!rc && cmd->dimm)
+		ndctl_refresh_dimm_flags(cmd->dimm);
  out:
 	cmd->status = rc;
 	return rc;
diff --git a/ndctl/lib/private.h b/ndctl/lib/private.h
index 4d8622978790..e5c56295556d 100644
--- a/ndctl/lib/private.h
+++ b/ndctl/lib/private.h
@@ -75,6 +75,7 @@ struct ndctl_dimm {
 	char *unique_id;
 	char *dimm_path;
 	char *dimm_buf;
+	char *bus_prefix;
 	int health_eventfd;
 	int buf_len;
 	int id;
diff --git a/ndctl/libndctl.h b/ndctl/libndctl.h
index 4d5cdbf6f619..b1bafd6d9788 100644
--- a/ndctl/libndctl.h
+++ b/ndctl/libndctl.h
@@ -223,6 +223,7 @@ int ndctl_dimm_is_active(struct ndctl_dimm *dimm);
 int ndctl_dimm_is_enabled(struct ndctl_dimm *dimm);
 int ndctl_dimm_disable(struct ndctl_dimm *dimm);
 int ndctl_dimm_enable(struct ndctl_dimm *dimm);
+void ndctl_refresh_dimm_flags(struct ndctl_dimm *dimm);
 
 struct ndctl_cmd;
 struct ndctl_cmd *ndctl_bus_cmd_new_ars_cap(struct ndctl_bus *bus,
-- 
2.34.1

Re: [ndctl PATCH v4] libndctl: Update nvdimm flags in ndctl_cmd_submit()

[Verma, Vishal L]

On Tue, 2022-01-25 at 02:28 +0530, Vaibhav Jain wrote:
> Presently after performing an inject-smart the nvdimm flags reported are
> out of date as shown below where no 'smart_notify' or 'flush_fail' flags
> were reported even though they are set after injecting the smart error:
> 
> $ sudo inject-smart -fU nmem0
> [
>   {
>     "dev":"nmem0",
>     "health":{
>       "health_state":"fatal",
>       "shutdown_state":"dirty",
>       "shutdown_count":0
>     }
>   }
> ]
> $ sudo cat /sys/class/nd/ndctl0/device/nmem0/papr/flags
> flush_fail smart_notify
> 
> This happens because nvdimm flags are only parsed once during its probe
> and not refreshed even after a inject-smart operation makes them out of
> date. To fix this the patch forces an update of nvdimm flags via newly
> introduced ndctl_refresh_dimm_flags() thats called successfully submitting
> a 'struct ndctl_cmd' in ndctl_cmd_submit(). This ensures that correct
> nvdimm flags are reported after an interaction with the kernel module which
> may trigger a change nvdimm-flags. With this implemented correct nvdimm
> flags are reported after a inject-smart operation:
> 
> $ sudo ndctl inject-smart -fU nmem0
> [
>   {
>     "dev":"nmem0",
>     "flag_failed_flush":true,
>     "flag_smart_event":true,
>     "health":{
>       "health_state":"fatal",
>       "shutdown_state":"dirty",
>       "shutdown_count":0
>     }
>   }
> ]
> 
> The patch refactors populate_dimm_attributes() to move the nvdimm flags
> parsing code to the newly introduced ndctl_refresh_dimm_flags()
> export. Since reading nvdimm flags requires constructing path using
> 'bus_prefix' which is only available during add_dimm(), the patch
> introduces a new member 'struct ndctl_dimm.bus_prefix' to cache its
> value. During ndctl_refresh_dimm_flags() the cached bus_prefix is used to
> read the contents of the nvdimm flag file and pass it on to the appropriate
> flag parsing function. Finally ndctl_refresh_dimm_flags() is invoked at the
> end of ndctl_cmd_submit() if nd-command submission succeeds.

I think instead of making it ndctl_cmd_submit()'s responsibility to
update any stale state, we should simply NDCTL_EXPORT the refresh
function (also rename it to conform to other ndctl_dimm functions -
ndctl_dimm_refresh_flags()). Then if any operation expects to change
state, it can call the refresh API directly.

In this case, ndctl/inject-smart.c would call
ndctl_dimm_refresh_flags() if its command submission succeeded.

Also some minor comments below.

> 
> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
> Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
> ---
> Changelog:
> 
> Since v3-Resend:
> 164009789816.744139.2870779016511283907.stgit@lep8c.aus.stglabs.ibm.com
> * Rebased this on top of latest ndctl-pending tree that includes changes to
> switch to meson build system.
> ---
>  ndctl/lib/libndctl.c | 52 ++++++++++++++++++++++++++++++++------------
>  ndctl/lib/private.h  |  1 +
>  ndctl/libndctl.h     |  1 +
>  3 files changed, 40 insertions(+), 14 deletions(-)
> 
> diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c
> index 5979a92c113c..abff4ececa27 100644
> --- a/ndctl/lib/libndctl.c
> +++ b/ndctl/lib/libndctl.c
> @@ -608,6 +608,7 @@ static void free_dimm(struct ndctl_dimm *dimm)
>  	free(dimm->unique_id);
>  	free(dimm->dimm_buf);
>  	free(dimm->dimm_path);
> +	free(dimm->bus_prefix);
>  	if (dimm->module)
>  		kmod_module_unref(dimm->module);
>  	if (dimm->health_eventfd > -1)
> @@ -1670,14 +1671,34 @@ static int ndctl_bind(struct ndctl_ctx *ctx, struct kmod_module *module,
>  static int ndctl_unbind(struct ndctl_ctx *ctx, const char *devpath);
>  static struct kmod_module *to_module(struct ndctl_ctx *ctx, const char *alias);
>  
> +void ndctl_refresh_dimm_flags(struct ndctl_dimm *dimm)
> +{
> +	struct ndctl_ctx *ctx = dimm->bus->ctx;
> +	char *path = dimm->dimm_buf;
> +	char buf[SYSFS_ATTR_SIZE];
> +
> +	/* Construct path to dimm flags sysfs file */
> +	sprintf(path, "%s/%s/flags", dimm->dimm_path, dimm->bus_prefix);
> +
> +	if (sysfs_read_attr(ctx, path, buf) < 0)
> +		return;
> +
> +	/* Reset the flags */
> +	dimm->flags.flags = 0;
> +	if (ndctl_bus_has_nfit(dimm->bus))
> +		parse_nfit_mem_flags(dimm, buf);
> +	else if (ndctl_bus_is_papr_scm(dimm->bus))
> +		parse_papr_flags(dimm, buf);
> +}
> +
>  static int populate_dimm_attributes(struct ndctl_dimm *dimm,
> -				    const char *dimm_base,
> -				    const char *bus_prefix)
> +				    const char *dimm_base)
>  {
>  	int i, rc = -1;
>  	char buf[SYSFS_ATTR_SIZE];
>  	struct ndctl_ctx *ctx = dimm->bus->ctx;
>  	char *path = calloc(1, strlen(dimm_base) + 100);
> +	const char *bus_prefix = dimm->bus_prefix;
>  
>  	if (!path)
>  		return -ENOMEM;
> @@ -1761,16 +1782,10 @@ static int populate_dimm_attributes(struct ndctl_dimm *dimm,
>  	}
>  
>  	sprintf(path, "%s/%s/flags", dimm_base, bus_prefix);
> -	if (sysfs_read_attr(ctx, path, buf) == 0) {
> -		if (ndctl_bus_has_nfit(dimm->bus))
> -			parse_nfit_mem_flags(dimm, buf);
> -		else if (ndctl_bus_is_papr_scm(dimm->bus)) {
> -			dimm->cmd_family = NVDIMM_FAMILY_PAPR;
> -			parse_papr_flags(dimm, buf);
> -		}
> -	}
> -
>  	dimm->health_eventfd = open(path, O_RDONLY|O_CLOEXEC);
> +
> +	ndctl_refresh_dimm_flags(dimm);
> +
>  	rc = 0;
>   err_read:
>  
> @@ -1826,8 +1841,9 @@ static int add_papr_dimm(struct ndctl_dimm *dimm, const char *dimm_base)
>  
>  		rc = 0;
>  	} else if (strcmp(buf, "nvdimm_test") == 0) {
> +		dimm->cmd_family = NVDIMM_FAMILY_PAPR;
>  		/* probe via common populate_dimm_attributes() */
> -		rc = populate_dimm_attributes(dimm, dimm_base, "papr");
> +		rc = populate_dimm_attributes(dimm, dimm_base);
>  	}
>  out:
>  	free(path);
> @@ -1924,9 +1940,13 @@ static void *add_dimm(void *parent, int id, const char *dimm_base)
>  	dimm->formats = formats;
>  	/* Check if the given dimm supports nfit */
>  	if (ndctl_bus_has_nfit(bus)) {
> -		rc = populate_dimm_attributes(dimm, dimm_base, "nfit");
> +		dimm->bus_prefix = strdup("nfit");
> +		rc = dimm->bus_prefix ?
> +			populate_dimm_attributes(dimm, dimm_base) : -ENOMEM
>  	} else if (ndctl_bus_has_of_node(bus)) {
> -		rc = add_papr_dimm(dimm, dimm_base);
> +		dimm->bus_prefix = strdup("papr");
> +		rc = dimm->bus_prefix ?
> +			add_papr_dimm(dimm, dimm_base) : -ENOMEM;

For both of the above, it would be a bit more readable to just return
ENOMEM directly after strdup() if it fails, and then carry on with
add_<foo>_dimm().

	dimm->bus_prefix = strdup("papr");
	if (!dimm->bus_prefix)
		return -ENOMEM;
	rc = add_papr_dimm(dimm, dimm_base);
	...

>  	}
>  
>  	if (rc == -ENODEV) {
> @@ -3506,6 +3526,10 @@ NDCTL_EXPORT int ndctl_cmd_submit(struct ndctl_cmd *cmd)
>  		rc = -ENXIO;
>  	}
>  	close(fd);
> +
> +	/* update dimm-flags if command submitted successfully */
> +	if (!rc && cmd->dimm)
> +		ndctl_refresh_dimm_flags(cmd->dimm);
>   out:
>  	cmd->status = rc;
>  	return rc;
> diff --git a/ndctl/lib/private.h b/ndctl/lib/private.h
> index 4d8622978790..e5c56295556d 100644
> --- a/ndctl/lib/private.h
> +++ b/ndctl/lib/private.h
> @@ -75,6 +75,7 @@ struct ndctl_dimm {
>  	char *unique_id;
>  	char *dimm_path;
>  	char *dimm_buf;
> +	char *bus_prefix;
>  	int health_eventfd;
>  	int buf_len;
>  	int id;
> diff --git a/ndctl/libndctl.h b/ndctl/libndctl.h
> index 4d5cdbf6f619..b1bafd6d9788 100644
> --- a/ndctl/libndctl.h
> +++ b/ndctl/libndctl.h
> @@ -223,6 +223,7 @@ int ndctl_dimm_is_active(struct ndctl_dimm *dimm);
>  int ndctl_dimm_is_enabled(struct ndctl_dimm *dimm);
>  int ndctl_dimm_disable(struct ndctl_dimm *dimm);
>  int ndctl_dimm_enable(struct ndctl_dimm *dimm);
> +void ndctl_refresh_dimm_flags(struct ndctl_dimm *dimm);
>  
>  struct ndctl_cmd;
>  struct ndctl_cmd *ndctl_bus_cmd_new_ars_cap(struct ndctl_bus *bus,

Re: [ndctl PATCH v4] libndctl: Update nvdimm flags in ndctl_cmd_submit()

[Vaibhav Jain]

Hi Vishal,

Thanks for reviewing this patch,

"Verma, Vishal L" <vishal.l.verma@intel.com> writes:

> On Tue, 2022-01-25 at 02:28 +0530, Vaibhav Jain wrote:
>> Presently after performing an inject-smart the nvdimm flags reported are
>> out of date as shown below where no 'smart_notify' or 'flush_fail' flags
>> were reported even though they are set after injecting the smart error:
>> 
>> $ sudo inject-smart -fU nmem0
>> [
>>   {
>>     "dev":"nmem0",
>>     "health":{
>>       "health_state":"fatal",
>>       "shutdown_state":"dirty",
>>       "shutdown_count":0
>>     }
>>   }
>> ]
>> $ sudo cat /sys/class/nd/ndctl0/device/nmem0/papr/flags
>> flush_fail smart_notify
>> 
>> This happens because nvdimm flags are only parsed once during its probe
>> and not refreshed even after a inject-smart operation makes them out of
>> date. To fix this the patch forces an update of nvdimm flags via newly
>> introduced ndctl_refresh_dimm_flags() thats called successfully submitting
>> a 'struct ndctl_cmd' in ndctl_cmd_submit(). This ensures that correct
>> nvdimm flags are reported after an interaction with the kernel module which
>> may trigger a change nvdimm-flags. With this implemented correct nvdimm
>> flags are reported after a inject-smart operation:
>> 
>> $ sudo ndctl inject-smart -fU nmem0
>> [
>>   {
>>     "dev":"nmem0",
>>     "flag_failed_flush":true,
>>     "flag_smart_event":true,
>>     "health":{
>>       "health_state":"fatal",
>>       "shutdown_state":"dirty",
>>       "shutdown_count":0
>>     }
>>   }
>> ]
>> 
>> The patch refactors populate_dimm_attributes() to move the nvdimm flags
>> parsing code to the newly introduced ndctl_refresh_dimm_flags()
>> export. Since reading nvdimm flags requires constructing path using
>> 'bus_prefix' which is only available during add_dimm(), the patch
>> introduces a new member 'struct ndctl_dimm.bus_prefix' to cache its
>> value. During ndctl_refresh_dimm_flags() the cached bus_prefix is used to
>> read the contents of the nvdimm flag file and pass it on to the appropriate
>> flag parsing function. Finally ndctl_refresh_dimm_flags() is invoked at the
>> end of ndctl_cmd_submit() if nd-command submission succeeds.
>
> I think instead of making it ndctl_cmd_submit()'s responsibility to
> update any stale state, we should simply NDCTL_EXPORT the refresh
> function (also rename it to conform to other ndctl_dimm functions -
> ndctl_dimm_refresh_flags()). Then if any operation expects to change
> state, it can call the refresh API directly.
>
> In this case, ndctl/inject-smart.c would call
> ndctl_dimm_refresh_flags() if its command submission succeeded.
Agree and will update v5 of the patch to
s/ndctl_refresh_dimm_flags/ndctl_dimm_refresh_flags/g

Also will make it a libndctl export that can be called after
smart-inject and before the nvdimm flags are reported.

>
> Also some minor comments below.
>
>> 
>> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
>> Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
>> ---
>> Changelog:
>> 
>> Since v3-Resend:
>> 164009789816.744139.2870779016511283907.stgit@lep8c.aus.stglabs.ibm.com
>> * Rebased this on top of latest ndctl-pending tree that includes changes to
>> switch to meson build system.
>> ---
>>  ndctl/lib/libndctl.c | 52 ++++++++++++++++++++++++++++++++------------
>>  ndctl/lib/private.h  |  1 +
>>  ndctl/libndctl.h     |  1 +
>>  3 files changed, 40 insertions(+), 14 deletions(-)
>> 
>> diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c
>> index 5979a92c113c..abff4ececa27 100644
>> --- a/ndctl/lib/libndctl.c
>> +++ b/ndctl/lib/libndctl.c
>> @@ -608,6 +608,7 @@ static void free_dimm(struct ndctl_dimm *dimm)
>>  	free(dimm->unique_id);
>>  	free(dimm->dimm_buf);
>>  	free(dimm->dimm_path);
>> +	free(dimm->bus_prefix);
>>  	if (dimm->module)
>>  		kmod_module_unref(dimm->module);
>>  	if (dimm->health_eventfd > -1)
>> @@ -1670,14 +1671,34 @@ static int ndctl_bind(struct ndctl_ctx *ctx, struct kmod_module *module,
>>  static int ndctl_unbind(struct ndctl_ctx *ctx, const char *devpath);
>>  static struct kmod_module *to_module(struct ndctl_ctx *ctx, const char *alias);
>>  
>> +void ndctl_refresh_dimm_flags(struct ndctl_dimm *dimm)
>> +{
>> +	struct ndctl_ctx *ctx = dimm->bus->ctx;
>> +	char *path = dimm->dimm_buf;
>> +	char buf[SYSFS_ATTR_SIZE];
>> +
>> +	/* Construct path to dimm flags sysfs file */
>> +	sprintf(path, "%s/%s/flags", dimm->dimm_path, dimm->bus_prefix);
>> +
>> +	if (sysfs_read_attr(ctx, path, buf) < 0)
>> +		return;
>> +
>> +	/* Reset the flags */
>> +	dimm->flags.flags = 0;
>> +	if (ndctl_bus_has_nfit(dimm->bus))
>> +		parse_nfit_mem_flags(dimm, buf);
>> +	else if (ndctl_bus_is_papr_scm(dimm->bus))
>> +		parse_papr_flags(dimm, buf);
>> +}
>> +
>>  static int populate_dimm_attributes(struct ndctl_dimm *dimm,
>> -				    const char *dimm_base,
>> -				    const char *bus_prefix)
>> +				    const char *dimm_base)
>>  {
>>  	int i, rc = -1;
>>  	char buf[SYSFS_ATTR_SIZE];
>>  	struct ndctl_ctx *ctx = dimm->bus->ctx;
>>  	char *path = calloc(1, strlen(dimm_base) + 100);
>> +	const char *bus_prefix = dimm->bus_prefix;
>>  
>>  	if (!path)
>>  		return -ENOMEM;
>> @@ -1761,16 +1782,10 @@ static int populate_dimm_attributes(struct ndctl_dimm *dimm,
>>  	}
>>  
>>  	sprintf(path, "%s/%s/flags", dimm_base, bus_prefix);
>> -	if (sysfs_read_attr(ctx, path, buf) == 0) {
>> -		if (ndctl_bus_has_nfit(dimm->bus))
>> -			parse_nfit_mem_flags(dimm, buf);
>> -		else if (ndctl_bus_is_papr_scm(dimm->bus)) {
>> -			dimm->cmd_family = NVDIMM_FAMILY_PAPR;
>> -			parse_papr_flags(dimm, buf);
>> -		}
>> -	}
>> -
>>  	dimm->health_eventfd = open(path, O_RDONLY|O_CLOEXEC);
>> +
>> +	ndctl_refresh_dimm_flags(dimm);
>> +
>>  	rc = 0;
>>   err_read:
>>  
>> @@ -1826,8 +1841,9 @@ static int add_papr_dimm(struct ndctl_dimm *dimm, const char *dimm_base)
>>  
>>  		rc = 0;
>>  	} else if (strcmp(buf, "nvdimm_test") == 0) {
>> +		dimm->cmd_family = NVDIMM_FAMILY_PAPR;
>>  		/* probe via common populate_dimm_attributes() */
>> -		rc = populate_dimm_attributes(dimm, dimm_base, "papr");
>> +		rc = populate_dimm_attributes(dimm, dimm_base);
>>  	}
>>  out:
>>  	free(path);
>> @@ -1924,9 +1940,13 @@ static void *add_dimm(void *parent, int id, const char *dimm_base)
>>  	dimm->formats = formats;
>>  	/* Check if the given dimm supports nfit */
>>  	if (ndctl_bus_has_nfit(bus)) {
>> -		rc = populate_dimm_attributes(dimm, dimm_base, "nfit");
>> +		dimm->bus_prefix = strdup("nfit");
>> +		rc = dimm->bus_prefix ?
>> +			populate_dimm_attributes(dimm, dimm_base) : -ENOMEM
>>  	} else if (ndctl_bus_has_of_node(bus)) {
>> -		rc = add_papr_dimm(dimm, dimm_base);
>> +		dimm->bus_prefix = strdup("papr");
>> +		rc = dimm->bus_prefix ?
>> +			add_papr_dimm(dimm, dimm_base) : -ENOMEM;
>
> For both of the above, it would be a bit more readable to just return
> ENOMEM directly after strdup() if it fails, and then carry on with
> add_<foo>_dimm().
>
> 	dimm->bus_prefix = strdup("papr");
> 	if (!dimm->bus_prefix)
> 		return -ENOMEM;
> 	rc = add_papr_dimm(dimm, dimm_base);
> 	...
>
Agree on the readability part but returning from there right away would
prevent the allocated 'struct ndctl_dimm *dimm' from being freed in the
error path. Also the function add_dimm() returns a 'void *' to 'struct
ndctl_dimm*' right now rather than an 'int'.

I propose updating the code as:

	if (ndctl_bus_has_nfit(bus)) {
		dimm->bus_prefix = strdup("nfit");
		if (!dimm->bus_prefix) {
			rc = -ENOMEM;
			goto out;
		}
		rc =  populate_dimm_attributes(dimm, dimm_base);
         }

>>  	}
>>  
>>  	if (rc == -ENODEV) {
>> @@ -3506,6 +3526,10 @@ NDCTL_EXPORT int ndctl_cmd_submit(struct ndctl_cmd *cmd)
>>  		rc = -ENXIO;
>>  	}
>>  	close(fd);
>> +
>> +	/* update dimm-flags if command submitted successfully */
>> +	if (!rc && cmd->dimm)
>> +		ndctl_refresh_dimm_flags(cmd->dimm);
>>   out:
>>  	cmd->status = rc;
>>  	return rc;
>> diff --git a/ndctl/lib/private.h b/ndctl/lib/private.h
>> index 4d8622978790..e5c56295556d 100644
>> --- a/ndctl/lib/private.h
>> +++ b/ndctl/lib/private.h
>> @@ -75,6 +75,7 @@ struct ndctl_dimm {
>>  	char *unique_id;
>>  	char *dimm_path;
>>  	char *dimm_buf;
>> +	char *bus_prefix;
>>  	int health_eventfd;
>>  	int buf_len;
>>  	int id;
>> diff --git a/ndctl/libndctl.h b/ndctl/libndctl.h
>> index 4d5cdbf6f619..b1bafd6d9788 100644
>> --- a/ndctl/libndctl.h
>> +++ b/ndctl/libndctl.h
>> @@ -223,6 +223,7 @@ int ndctl_dimm_is_active(struct ndctl_dimm *dimm);
>>  int ndctl_dimm_is_enabled(struct ndctl_dimm *dimm);
>>  int ndctl_dimm_disable(struct ndctl_dimm *dimm);
>>  int ndctl_dimm_enable(struct ndctl_dimm *dimm);
>> +void ndctl_refresh_dimm_flags(struct ndctl_dimm *dimm);
>>  
>>  struct ndctl_cmd;
>>  struct ndctl_cmd *ndctl_bus_cmd_new_ars_cap(struct ndctl_bus *bus,
>

-- 
Cheers
~ Vaibhav

Re: [ndctl PATCH v4] libndctl: Update nvdimm flags in ndctl_cmd_submit()

[Verma, Vishal L]

On Sat, 2022-02-19 at 18:09 +0530, Vaibhav Jain wrote:
> 
> > > @@ -1924,9 +1940,13 @@ static void *add_dimm(void *parent, int id, const char *dimm_base)
> > >  	dimm->formats = formats;
> > >  	/* Check if the given dimm supports nfit */
> > >  	if (ndctl_bus_has_nfit(bus)) {
> > > -		rc = populate_dimm_attributes(dimm, dimm_base, "nfit");
> > > +		dimm->bus_prefix = strdup("nfit");
> > > +		rc = dimm->bus_prefix ?
> > > +			populate_dimm_attributes(dimm, dimm_base) : -ENOMEM
> > >  	} else if (ndctl_bus_has_of_node(bus)) {
> > > -		rc = add_papr_dimm(dimm, dimm_base);
> > > +		dimm->bus_prefix = strdup("papr");
> > > +		rc = dimm->bus_prefix ?
> > > +			add_papr_dimm(dimm, dimm_base) : -ENOMEM;
> > 
> > For both of the above, it would be a bit more readable to just return
> > ENOMEM directly after strdup() if it fails, and then carry on with
> > add_<foo>_dimm().
> > 
> > 	dimm->bus_prefix = strdup("papr");
> > 	if (!dimm->bus_prefix)
> > 		return -ENOMEM;
> > 	rc = add_papr_dimm(dimm, dimm_base);
> > 	...
> > 
> Agree on the readability part but returning from there right away would
> prevent the allocated 'struct ndctl_dimm *dimm' from being freed in the
> error path. Also the function add_dimm() returns a 'void *' to 'struct
> ndctl_dimm*' right now rather than an 'int'.
> 
> I propose updating the code as:
> 
> 	if (ndctl_bus_has_nfit(bus)) {
> 		dimm->bus_prefix = strdup("nfit");
> 		if (!dimm->bus_prefix) {
> 			rc = -ENOMEM;
> 			goto out;
> 		}
> 		rc =  populate_dimm_attributes(dimm, dimm_base);
>          }

Yes, that looks good, thanks!

> 
> > >  	}
> > >  
> > >  	if (rc == -ENODEV) {
> > > @@ -3506,6 +3526,10 @@ NDCTL_EXPORT int ndctl_cmd_submit(struct ndctl_cmd *cmd)
> > >  		rc = -ENXIO;
> > >  	}
> > >  	close(fd);
> > > +
> > > +	/* update dimm-flags if command submitted successfully */
> > > +	if (!rc && cmd->dimm)
> > > +		ndctl_refresh_dimm_flags(cmd->dimm);
> > >   out:
> > >  	cmd->status = rc;
> > >  	return rc;
> > > diff --git a/ndctl/lib/private.h b/ndctl/lib/private.h
> > > index 4d8622978790..e5c56295556d 100644
> > > --- a/ndctl/lib/private.h
> > > +++ b/ndctl/lib/private.h
> > > @@ -75,6 +75,7 @@ struct ndctl_dimm {
> > >  	char *unique_id;
> > >  	char *dimm_path;
> > >  	char *dimm_buf;
> > > +	char *bus_prefix;
> > >  	int health_eventfd;
> > >  	int buf_len;
> > >  	int id;
> > > diff --git a/ndctl/libndctl.h b/ndctl/libndctl.h
> > > index 4d5cdbf6f619..b1bafd6d9788 100644
> > > --- a/ndctl/libndctl.h
> > > +++ b/ndctl/libndctl.h
> > > @@ -223,6 +223,7 @@ int ndctl_dimm_is_active(struct ndctl_dimm *dimm);
> > >  int ndctl_dimm_is_enabled(struct ndctl_dimm *dimm);
> > >  int ndctl_dimm_disable(struct ndctl_dimm *dimm);
> > >  int ndctl_dimm_enable(struct ndctl_dimm *dimm);
> > > +void ndctl_refresh_dimm_flags(struct ndctl_dimm *dimm);
> > >  
> > >  struct ndctl_cmd;
> > >  struct ndctl_cmd *ndctl_bus_cmd_new_ars_cap(struct ndctl_bus *bus,
> > 
> 

Re: [ndctl PATCH v4] libndctl: Update nvdimm flags in ndctl_cmd_submit()

[Vaibhav Jain]

Thanks Vishal,

I have addressed your review comments in v5 of the patch here at
https://lore.kernel.org/nvdimm/20220222121519.1674117-1-vaibhav@linux.ibm.com

~ Vaibhav

"Verma, Vishal L" <vishal.l.verma@intel.com> writes:

> On Sat, 2022-02-19 at 18:09 +0530, Vaibhav Jain wrote:
>> 
>> > > @@ -1924,9 +1940,13 @@ static void *add_dimm(void *parent, int id, const char *dimm_base)
>> > >  	dimm->formats = formats;
>> > >  	/* Check if the given dimm supports nfit */
>> > >  	if (ndctl_bus_has_nfit(bus)) {
>> > > -		rc = populate_dimm_attributes(dimm, dimm_base, "nfit");
>> > > +		dimm->bus_prefix = strdup("nfit");
>> > > +		rc = dimm->bus_prefix ?
>> > > +			populate_dimm_attributes(dimm, dimm_base) : -ENOMEM
>> > >  	} else if (ndctl_bus_has_of_node(bus)) {
>> > > -		rc = add_papr_dimm(dimm, dimm_base);
>> > > +		dimm->bus_prefix = strdup("papr");
>> > > +		rc = dimm->bus_prefix ?
>> > > +			add_papr_dimm(dimm, dimm_base) : -ENOMEM;
>> > 
>> > For both of the above, it would be a bit more readable to just return
>> > ENOMEM directly after strdup() if it fails, and then carry on with
>> > add_<foo>_dimm().
>> > 
>> > 	dimm->bus_prefix = strdup("papr");
>> > 	if (!dimm->bus_prefix)
>> > 		return -ENOMEM;
>> > 	rc = add_papr_dimm(dimm, dimm_base);
>> > 	...
>> > 
>> Agree on the readability part but returning from there right away would
>> prevent the allocated 'struct ndctl_dimm *dimm' from being freed in the
>> error path. Also the function add_dimm() returns a 'void *' to 'struct
>> ndctl_dimm*' right now rather than an 'int'.
>> 
>> I propose updating the code as:
>> 
>> 	if (ndctl_bus_has_nfit(bus)) {
>> 		dimm->bus_prefix = strdup("nfit");
>> 		if (!dimm->bus_prefix) {
>> 			rc = -ENOMEM;
>> 			goto out;
>> 		}
>> 		rc =  populate_dimm_attributes(dimm, dimm_base);
>>          }
>
> Yes, that looks good, thanks!
>
>> 
>> > >  	}
>> > >  
>> > >  	if (rc == -ENODEV) {
>> > > @@ -3506,6 +3526,10 @@ NDCTL_EXPORT int ndctl_cmd_submit(struct ndctl_cmd *cmd)
>> > >  		rc = -ENXIO;
>> > >  	}
>> > >  	close(fd);
>> > > +
>> > > +	/* update dimm-flags if command submitted successfully */
>> > > +	if (!rc && cmd->dimm)
>> > > +		ndctl_refresh_dimm_flags(cmd->dimm);
>> > >   out:
>> > >  	cmd->status = rc;
>> > >  	return rc;
>> > > diff --git a/ndctl/lib/private.h b/ndctl/lib/private.h
>> > > index 4d8622978790..e5c56295556d 100644
>> > > --- a/ndctl/lib/private.h
>> > > +++ b/ndctl/lib/private.h
>> > > @@ -75,6 +75,7 @@ struct ndctl_dimm {
>> > >  	char *unique_id;
>> > >  	char *dimm_path;
>> > >  	char *dimm_buf;
>> > > +	char *bus_prefix;
>> > >  	int health_eventfd;
>> > >  	int buf_len;
>> > >  	int id;
>> > > diff --git a/ndctl/libndctl.h b/ndctl/libndctl.h
>> > > index 4d5cdbf6f619..b1bafd6d9788 100644
>> > > --- a/ndctl/libndctl.h
>> > > +++ b/ndctl/libndctl.h
>> > > @@ -223,6 +223,7 @@ int ndctl_dimm_is_active(struct ndctl_dimm *dimm);
>> > >  int ndctl_dimm_is_enabled(struct ndctl_dimm *dimm);
>> > >  int ndctl_dimm_disable(struct ndctl_dimm *dimm);
>> > >  int ndctl_dimm_enable(struct ndctl_dimm *dimm);
>> > > +void ndctl_refresh_dimm_flags(struct ndctl_dimm *dimm);
>> > >  
>> > >  struct ndctl_cmd;
>> > >  struct ndctl_cmd *ndctl_bus_cmd_new_ars_cap(struct ndctl_bus *bus,
>> > 
>> 
>

-- 
Cheers
~ Vaibhav