[ndctl] libndctl: set errno for routines that don't return an error status

Commit Message

Verma, Vishal L Oct. 4, 2018, 10:34 p.m. UTC

For routines that return a UINT_MAX or UL{L}ONG_MAX, there isn't a way
to get any information as to what went wrong. Set errno in such routines
so that the callers can get some additional context about the error.

Reported-by: Lukasz Dorau <[e-mail]>
Cc: Dan Williams <[e-mail]>
Signed-off-by: Vishal Verma <[e-mail]>
---
 ndctl/lib/dimm.c     |  8 +++--
 ndctl/lib/hpe1.c     | 79 +++++++++++++++++++++++++++++++++++++-------
 ndctl/lib/inject.c   |  2 ++
 ndctl/lib/intel.c    | 45 +++++++++++++++++++++----
 ndctl/lib/libndctl.c | 54 ++++++++++++++++++++++--------
 ndctl/lib/msft.c     | 27 ++++++++++++---
 6 files changed, 177 insertions(+), 38 deletions(-)

Comments

Dan Williams Oct. 4, 2018, 10:54 p.m. UTC | #1

On Thu, 2018-10-04 at 16:34 -0600, Vishal Verma wrote:
> For routines that return a UINT_MAX or UL{L}ONG_MAX, there isn't a
> way
> to get any information as to what went wrong. Set errno in such
> routines
> so that the callers can get some additional context about the error.

Looks ok, but why EOVERFLOW and not ENOMEM for the out of resource
conditions?

Verma, Vishal L Oct. 4, 2018, 11:01 p.m. UTC | #2

On Thu, 2018-10-04 at 15:54 -0700, Williams, Dan J wrote:
> On Thu, 2018-10-04 at 16:34 -0600, Vishal Verma wrote:
> > For routines that return a UINT_MAX or UL{L}ONG_MAX, there isn't a
> > way
> > to get any information as to what went wrong. Set errno in such
> > routines
> > so that the callers can get some additional context about the
> > error.
> 
> Looks ok, but why EOVERFLOW and not ENOMEM for the out of resource
> conditions?

I debated between that and also ENOSPC, but nothing seemed like an
exact fit for a buffer too small.. Mainly not ENOMEM because we aren't
actually trying to allocate memory as a part of this?

Dan Williams Oct. 4, 2018, 11:11 p.m. UTC | #3

On Thu, 2018-10-04 at 16:01 -0700, Verma, Vishal L wrote:
> On Thu, 2018-10-04 at 15:54 -0700, Williams, Dan J wrote:
> > On Thu, 2018-10-04 at 16:34 -0600, Vishal Verma wrote:
> > > For routines that return a UINT_MAX or UL{L}ONG_MAX, there isn't
> > > a
> > > way
> > > to get any information as to what went wrong. Set errno in such
> > > routines
> > > so that the callers can get some additional context about the
> > > error.
> > 
> > Looks ok, but why EOVERFLOW and not ENOMEM for the out of resource
> > conditions?
> 
> I debated between that and also ENOSPC, but nothing seemed like an
> exact fit for a buffer too small.. Mainly not ENOMEM because we
> aren't
> actually trying to allocate memory as a part of this?

That's true, but the effect is the same, couldn't get enough resource
to complete the operation. I would expect EOVERFLOW for trying to store
a 64-bit quantity in a 32-bit field.

Verma, Vishal L Oct. 4, 2018, 11:13 p.m. UTC | #4

On Thu, 2018-10-04 at 16:11 -0700, Williams, Dan J wrote:
> On Thu, 2018-10-04 at 16:01 -0700, Verma, Vishal L wrote:
> > On Thu, 2018-10-04 at 15:54 -0700, Williams, Dan J wrote:
> > > On Thu, 2018-10-04 at 16:34 -0600, Vishal Verma wrote:
> > > > For routines that return a UINT_MAX or UL{L}ONG_MAX, there isn't
> > > > a
> > > > way
> > > > to get any information as to what went wrong. Set errno in such
> > > > routines
> > > > so that the callers can get some additional context about the
> > > > error.
> > > 
> > > Looks ok, but why EOVERFLOW and not ENOMEM for the out of resource
> > > conditions?
> > 
> > I debated between that and also ENOSPC, but nothing seemed like an
> > exact fit for a buffer too small.. Mainly not ENOMEM because we
> > aren't
> > actually trying to allocate memory as a part of this?
> 
> That's true, but the effect is the same, couldn't get enough resource
> to complete the operation. I would expect EOVERFLOW for trying to store
> a 64-bit quantity in a 32-bit field.
> 

Good point, I'll change to ENOMEM.

Patch

diff --git a/ndctl/lib/dimm.c b/ndctl/lib/dimm.c
index b3e032e..0299b41 100644
--- a/ndctl/lib/dimm.c
+++ b/ndctl/lib/dimm.c
@@ -565,17 +565,21 @@  NDCTL_EXPORT unsigned long ndctl_dimm_get_available_labels(
 {
 	struct ndctl_ctx *ctx = ndctl_dimm_get_ctx(dimm);
 	char *path = dimm->dimm_buf;
-	int len = dimm->buf_len;
+	int rc, len = dimm->buf_len;
 	char buf[20];
 
 	if (snprintf(path, len, "%s/available_slots", dimm->dimm_path) >= len) {
 		err(ctx, "%s: buffer too small!\n",
 				ndctl_dimm_get_devname(dimm));
+		errno = EOVERFLOW;
 		return ULONG_MAX;
 	}
 
-	if (sysfs_read_attr(ctx, path, buf) < 0)
+	rc = sysfs_read_attr(ctx, path, buf);
+	if (rc < 0) {
+		errno = -rc;
 		return ULONG_MAX;
+	}
 
 	return strtoul(buf, NULL, 0);
 }
diff --git a/ndctl/lib/hpe1.c b/ndctl/lib/hpe1.c
index dbc1ff0..b26120e 100644
--- a/ndctl/lib/hpe1.c
+++ b/ndctl/lib/hpe1.c
@@ -90,9 +90,13 @@  static unsigned int hpe1_cmd_smart_get_flags(struct ndctl_cmd *cmd)
 {
 	unsigned int hpe1flags;
 	unsigned int flags;
+	int rc;
 
-	if (hpe1_smart_valid(cmd) < 0)
+	rc = hpe1_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	hpe1flags = CMD_HPE1_SMART(cmd)->out_valid_flags;
 	flags = 0;
@@ -118,9 +122,13 @@  static unsigned int hpe1_cmd_smart_get_health(struct ndctl_cmd *cmd)
 {
 	unsigned char hpe1health;
 	unsigned int health;
+	int rc;
 
-	if (hpe1_smart_valid(cmd) < 0)
+	rc = hpe1_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	hpe1health = CMD_HPE1_SMART(cmd)->stat_summary;
 	health = 0;
@@ -136,16 +144,26 @@  static unsigned int hpe1_cmd_smart_get_health(struct ndctl_cmd *cmd)
 
 static unsigned int hpe1_cmd_smart_get_media_temperature(struct ndctl_cmd *cmd)
 {
-	if (hpe1_smart_valid(cmd) < 0)
+	int rc;
+
+	rc = hpe1_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	return CMD_HPE1_SMART(cmd)->curr_temp;
 }
 
 static unsigned int hpe1_cmd_smart_get_spares(struct ndctl_cmd *cmd)
 {
-	if (hpe1_smart_valid(cmd) < 0)
+	int rc;
+
+	rc = hpe1_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	return CMD_HPE1_SMART(cmd)->spare_blocks;
 }
@@ -154,9 +172,13 @@  static unsigned int hpe1_cmd_smart_get_alarm_flags(struct ndctl_cmd *cmd)
 {
 	unsigned int hpe1flags;
 	unsigned int flags;
+	int rc;
 
-	if (hpe1_smart_valid(cmd) < 0)
+	rc = hpe1_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	hpe1flags = CMD_HPE1_SMART(cmd)->alarm_trips;
 	flags = 0;
@@ -170,8 +192,13 @@  static unsigned int hpe1_cmd_smart_get_alarm_flags(struct ndctl_cmd *cmd)
 
 static unsigned int hpe1_cmd_smart_get_life_used(struct ndctl_cmd *cmd)
 {
-	if (hpe1_smart_valid(cmd) < 0)
+	int rc;
+
+	rc = hpe1_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	return CMD_HPE1_SMART(cmd)->device_life;
 }
@@ -179,9 +206,13 @@  static unsigned int hpe1_cmd_smart_get_life_used(struct ndctl_cmd *cmd)
 static unsigned int hpe1_cmd_smart_get_shutdown_state(struct ndctl_cmd *cmd)
 {
 	unsigned int shutdown;
+	int rc;
 
-	if (hpe1_smart_valid(cmd) < 0)
+	rc = hpe1_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	shutdown = CMD_HPE1_SMART(cmd)->last_shutdown_stat;
 	if (shutdown == NDN_HPE1_SMART_LASTSAVEGOOD)
@@ -192,16 +223,26 @@  static unsigned int hpe1_cmd_smart_get_shutdown_state(struct ndctl_cmd *cmd)
 
 static unsigned int hpe1_cmd_smart_get_vendor_size(struct ndctl_cmd *cmd)
 {
-	if (hpe1_smart_valid(cmd) < 0)
+	int rc;
+
+	rc = hpe1_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	return CMD_HPE1_SMART(cmd)->vndr_spec_data_size;
 }
 
 static unsigned char *hpe1_cmd_smart_get_vendor_data(struct ndctl_cmd *cmd)
 {
-	if (hpe1_smart_valid(cmd) < 0)
+	int rc;
+
+	rc = hpe1_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return NULL;
+	}
 
 	return CMD_HPE1_SMART(cmd)->vnd_spec_data;
 }
@@ -265,9 +306,13 @@  static unsigned int hpe1_cmd_smart_threshold_get_alarm_control(struct ndctl_cmd
 {
 	unsigned int hpe1flags;
 	unsigned int flags;
+	int rc;
 
-	if (hpe1_smart_threshold_valid(cmd) < 0)
+	rc = hpe1_smart_threshold_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	hpe1flags = CMD_HPE1_SMART_THRESH(cmd)->threshold_alarm_ctl;
 	flags = 0;
@@ -282,16 +327,26 @@  static unsigned int hpe1_cmd_smart_threshold_get_alarm_control(struct ndctl_cmd
 static unsigned int hpe1_cmd_smart_threshold_get_media_temperature(
 		struct ndctl_cmd *cmd)
 {
-	if (hpe1_smart_threshold_valid(cmd) < 0)
+	int rc;
+
+	rc = hpe1_smart_threshold_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	return CMD_HPE1_SMART_THRESH(cmd)->temp_threshold;
 }
 
 static unsigned int hpe1_cmd_smart_threshold_get_spares(struct ndctl_cmd *cmd)
 {
-	if (hpe1_smart_threshold_valid(cmd) < 0)
+	int rc;
+
+	rc = hpe1_smart_threshold_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	return CMD_HPE1_SMART_THRESH(cmd)->spare_block_threshold;
 }
diff --git a/ndctl/lib/inject.c b/ndctl/lib/inject.c
index 268c5cd..2b0702e 100644
--- a/ndctl/lib/inject.c
+++ b/ndctl/lib/inject.c
@@ -498,6 +498,7 @@  NDCTL_EXPORT unsigned long long ndctl_bb_get_block(struct ndctl_bb *bb)
 {
 	if (bb)
 		return bb->block;
+	errno = EINVAL;
 	return ULLONG_MAX;
 }
 
@@ -505,5 +506,6 @@  NDCTL_EXPORT unsigned long long ndctl_bb_get_count(struct ndctl_bb *bb)
 {
 	if (bb)
 		return bb->count;
+	errno = EINVAL;
 	return ULLONG_MAX;
 }
diff --git a/ndctl/lib/intel.c b/ndctl/lib/intel.c
index 0abea1e..744386f 100644
--- a/ndctl/lib/intel.c
+++ b/ndctl/lib/intel.c
@@ -85,8 +85,12 @@  static int intel_smart_valid(struct ndctl_cmd *cmd)
 #define intel_smart_get_field(cmd, field) \
 static unsigned int intel_cmd_smart_get_##field(struct ndctl_cmd *cmd) \
 { \
-	if (intel_smart_valid(cmd) < 0) \
+	int rc; \
+	rc = intel_smart_valid(cmd); \
+	if (rc < 0) { \
+		errno = -rc; \
 		return UINT_MAX; \
+	} \
 	return cmd->intel->smart.field; \
 }
 
@@ -173,8 +177,12 @@  static int intel_smart_threshold_valid(struct ndctl_cmd *cmd)
 static unsigned int intel_cmd_smart_threshold_get_##field( \
 			struct ndctl_cmd *cmd) \
 { \
-	if (intel_smart_threshold_valid(cmd) < 0) \
+	int rc; \
+	rc = intel_smart_threshold_valid(cmd); \
+	if (rc < 0) { \
+		errno = -rc; \
 		return UINT_MAX; \
+	} \
 	return cmd->intel->thresh.field; \
 }
 
@@ -431,8 +439,12 @@  static int intel_fw_get_info_valid(struct ndctl_cmd *cmd)
 static unsigned int intel_cmd_fw_info_get_##field( \
 			struct ndctl_cmd *cmd) \
 { \
-	if (intel_fw_get_info_valid(cmd) < 0) \
+	int rc; \
+	rc = intel_fw_get_info_valid(cmd); \
+	if (rc < 0) { \
+		errno = -rc; \
 		return UINT_MAX; \
+	} \
 	return cmd->intel->info.field; \
 }
 
@@ -440,8 +452,12 @@  static unsigned int intel_cmd_fw_info_get_##field( \
 static unsigned long long intel_cmd_fw_info_get_##field( \
 			struct ndctl_cmd *cmd) \
 { \
-	if (intel_fw_get_info_valid(cmd) < 0) \
+	int rc; \
+	rc = intel_fw_get_info_valid(cmd); \
+	if (rc < 0) { \
+		errno = -rc; \
 		return ULLONG_MAX; \
+	} \
 	return cmd->intel->info.field; \
 }
 
@@ -454,8 +470,13 @@  intel_fw_info_get_field64(cmd, run_version);
 static unsigned long long intel_cmd_fw_info_get_updated_version(
 		struct ndctl_cmd *cmd)
 {
-	if (intel_fw_get_info_valid(cmd) < 0)
+	int rc;
+
+	rc = intel_fw_get_info_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return ULLONG_MAX;
+	}
 	return cmd->intel->info.updated_version;
 
 }
@@ -488,8 +509,13 @@  static int intel_fw_start_valid(struct ndctl_cmd *cmd)
 
 static unsigned int intel_cmd_fw_start_get_context(struct ndctl_cmd *cmd)
 {
-	if (intel_fw_start_valid(cmd) < 0)
+	int rc;
+
+	rc = intel_fw_start_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 	return cmd->intel->start.context;
 }
 
@@ -580,8 +606,13 @@  static int intel_fw_fquery_valid(struct ndctl_cmd *cmd)
 static unsigned long long
 intel_cmd_fw_fquery_get_fw_rev(struct ndctl_cmd *cmd)
 {
-	if (intel_fw_fquery_valid(cmd) < 0)
+	int rc;
+
+	rc = intel_fw_fquery_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return ULLONG_MAX;
+	}
 	return cmd->intel->fquery.updated_fw_rev;
 }
 
diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c
index 4ceb70e..1506e53 100644
--- a/ndctl/lib/libndctl.c
+++ b/ndctl/lib/libndctl.c
@@ -1112,12 +1112,15 @@  NDCTL_EXPORT unsigned long long ndctl_region_get_resource(struct ndctl_region *r
 	if (snprintf(path, len, "%s/resource", region->region_path) >= len) {
 		err(ctx, "%s: buffer too small!\n",
 				ndctl_region_get_devname(region));
+		errno = EOVERFLOW;
 		return ULLONG_MAX;
 	}
 
 	rc = sysfs_read_attr(ctx, path, buf);
-	if (rc < 0)
+	if (rc < 0) {
+		errno = -rc;
 		return ULLONG_MAX;
+	}
 
 	return strtoull(buf, NULL, 0);
 }
@@ -1256,9 +1259,13 @@  NDCTL_EXPORT unsigned int ndctl_bus_get_scrub_count(struct ndctl_bus *bus)
 {
 	unsigned int scrub_count = 0;
 	bool active = false;
+	int rc;
 
-	if (__ndctl_bus_get_scrub_state(bus, &scrub_count, &active))
+	rc = __ndctl_bus_get_scrub_state(bus, &scrub_count, &active);
+	if (rc) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 	return scrub_count;
 }
 
@@ -1720,15 +1727,19 @@  NDCTL_EXPORT unsigned int ndctl_dimm_get_health(struct ndctl_dimm *dimm)
 	unsigned int health;
 	struct ndctl_ctx *ctx = ndctl_dimm_get_ctx(dimm);
 	const char *devname = ndctl_dimm_get_devname(dimm);
+	int rc;
 
 	cmd = ndctl_dimm_cmd_new_smart(dimm);
 	if (!cmd) {
 		err(ctx, "%s: no smart command support\n", devname);
 		return UINT_MAX;
 	}
-	if (ndctl_cmd_submit(cmd)) {
+	rc = ndctl_cmd_submit(cmd);
+	if (rc) {
 		err(ctx, "%s: smart command failed\n", devname);
 		ndctl_cmd_unref(cmd);
+		if (rc < 0)
+			errno = -rc;
 		return UINT_MAX;
 	}
 
@@ -1743,15 +1754,19 @@  NDCTL_EXPORT unsigned int ndctl_dimm_get_flags(struct ndctl_dimm *dimm)
 	unsigned int flags;
 	struct ndctl_ctx *ctx = ndctl_dimm_get_ctx(dimm);
 	const char *devname = ndctl_dimm_get_devname(dimm);
+	int rc;
 
 	cmd = ndctl_dimm_cmd_new_smart(dimm);
 	if (!cmd) {
 		dbg(ctx, "%s: no smart command support\n", devname);
 		return UINT_MAX;
 	}
-	if (ndctl_cmd_submit(cmd)) {
+	rc = ndctl_cmd_submit(cmd);
+	if (rc) {
 		dbg(ctx, "%s: smart command failed\n", devname);
 		ndctl_cmd_unref(cmd);
+		if (rc < 0)
+			errno = -rc;
 		return UINT_MAX;
 	}
 
@@ -1769,6 +1784,7 @@  NDCTL_EXPORT int ndctl_dimm_is_flag_supported(struct ndctl_dimm *dimm,
 
 NDCTL_EXPORT unsigned int ndctl_dimm_get_event_flags(struct ndctl_dimm *dimm)
 {
+	int rc;
 	struct ndctl_cmd *cmd = NULL;
 	unsigned int alarm_flags, event_flags = 0;
 	struct ndctl_ctx *ctx = ndctl_dimm_get_ctx(dimm);
@@ -1779,9 +1795,12 @@  NDCTL_EXPORT unsigned int ndctl_dimm_get_event_flags(struct ndctl_dimm *dimm)
 		err(ctx, "%s: no smart command support\n", devname);
 		return UINT_MAX;
 	}
-	if (ndctl_cmd_submit(cmd)) {
+	rc = ndctl_cmd_submit(cmd);
+	if (rc) {
 		err(ctx, "%s: smart command failed\n", devname);
 		ndctl_cmd_unref(cmd);
+		if (rc < 0)
+			errno = -rc;
 		return UINT_MAX;
 	}
 
@@ -2166,7 +2185,7 @@  NDCTL_EXPORT unsigned long long ndctl_region_get_available_size(
 	unsigned int nstype = ndctl_region_get_nstype(region);
 	struct ndctl_ctx *ctx = ndctl_region_get_ctx(region);
 	char *path = region->region_buf;
-	int len = region->buf_len;
+	int rc, len = region->buf_len;
 	char buf[SYSFS_ATTR_SIZE];
 
 	switch (nstype) {
@@ -2180,11 +2199,15 @@  NDCTL_EXPORT unsigned long long ndctl_region_get_available_size(
 	if (snprintf(path, len, "%s/available_size", region->region_path) >= len) {
 		err(ctx, "%s: buffer too small!\n",
 				ndctl_region_get_devname(region));
+		errno = EOVERFLOW;
 		return ULLONG_MAX;
 	}
 
-	if (sysfs_read_attr(ctx, path, buf) < 0)
+	rc = sysfs_read_attr(ctx, path, buf);
+	if (rc < 0) {
+		errno = -rc;
 		return ULLONG_MAX;
+	}
 
 	return strtoull(buf, NULL, 0);
 }
@@ -2195,7 +2218,7 @@  NDCTL_EXPORT unsigned long long ndctl_region_get_max_available_extent(
 	unsigned int nstype = ndctl_region_get_nstype(region);
 	struct ndctl_ctx *ctx = ndctl_region_get_ctx(region);
 	char *path = region->region_buf;
-	int len = region->buf_len;
+	int rc, len = region->buf_len;
 	char buf[SYSFS_ATTR_SIZE];
 
 	switch (nstype) {
@@ -2210,12 +2233,15 @@  NDCTL_EXPORT unsigned long long ndctl_region_get_max_available_extent(
 		     "%s/max_available_extent", region->region_path) >= len) {
 		err(ctx, "%s: buffer too small!\n",
 				ndctl_region_get_devname(region));
+		errno = EOVERFLOW;
 		return ULLONG_MAX;
 	}
 
 	/* fall back to legacy behavior if max extents is not exported */
-	if (sysfs_read_attr(ctx, path, buf) < 0) {
+	rc = sysfs_read_attr(ctx, path, buf);
+	if (rc < 0) {
 		dbg(ctx, "max extents attribute not exported on older kernels\n");
+		errno = -rc;
 		return ULLONG_MAX;
 	}
 
@@ -4017,9 +4043,10 @@  NDCTL_EXPORT unsigned int ndctl_namespace_get_supported_sector_size(
 	if (ndns->lbasize.num == 0)
 		return 0;
 
-	if (i < 0 || i > ndns->lbasize.num)
+	if (i < 0 || i > ndns->lbasize.num) {
+		errno = EINVAL;
 		return UINT_MAX;
-	else
+	} else
 		return ndns->lbasize.supported[i];
 }
 
@@ -4428,9 +4455,10 @@  NDCTL_EXPORT unsigned int ndctl_btt_get_id(struct ndctl_btt *btt)
 NDCTL_EXPORT unsigned int ndctl_btt_get_supported_sector_size(
 		struct ndctl_btt *btt, int i)
 {
-	if (i < 0 || i > btt->lbasize.num)
+	if (i < 0 || i > btt->lbasize.num) {
+		errno = EINVAL;
 		return UINT_MAX;
-	else
+	} else
 		return btt->lbasize.supported[i];
 }
 
diff --git a/ndctl/lib/msft.c b/ndctl/lib/msft.c
index e15bc07..19453cd 100644
--- a/ndctl/lib/msft.c
+++ b/ndctl/lib/msft.c
@@ -77,8 +77,13 @@  static int msft_smart_valid(struct ndctl_cmd *cmd)
 
 static unsigned int msft_cmd_smart_get_flags(struct ndctl_cmd *cmd)
 {
-	if (msft_smart_valid(cmd) < 0)
+	int rc;
+
+	rc = msft_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	/* below health data can be retrieved via MSFT _DSM function 11 */
 	return NDN_MSFT_SMART_HEALTH_VALID |
@@ -103,9 +108,13 @@  static unsigned int msft_cmd_smart_get_health(struct ndctl_cmd *cmd)
 {
 	unsigned int health;
 	unsigned int num;
+	int rc;
 
-	if (msft_smart_valid(cmd) < 0)
+	rc = msft_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	num = num_set_bit_health(CMD_MSFT_SMART(cmd)->health);
 	if (num == 0)
@@ -122,16 +131,26 @@  static unsigned int msft_cmd_smart_get_health(struct ndctl_cmd *cmd)
 
 static unsigned int msft_cmd_smart_get_media_temperature(struct ndctl_cmd *cmd)
 {
-	if (msft_smart_valid(cmd) < 0)
+	int rc;
+
+	rc = msft_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	return CMD_MSFT_SMART(cmd)->temp * 16;
 }
 
 static unsigned int msft_cmd_smart_get_life_used(struct ndctl_cmd *cmd)
 {
-	if (msft_smart_valid(cmd) < 0)
+	int rc;
+
+	rc = msft_smart_valid(cmd);
+	if (rc < 0) {
+		errno = -rc;
 		return UINT_MAX;
+	}
 
 	return 100 - CMD_MSFT_SMART(cmd)->nvm_lifetime;
 }