diff mbox series

[7/7] scsi: mpt3sas: Introduce sas_ncq_prio_supported sysfs sttribute

Message ID 20210802090232.1166195-8-damien.lemoal@wdc.com
State New
Headers show
Series libata cleanups and improvements | expand

Commit Message

Damien Le Moal Aug. 2, 2021, 9:02 a.m. UTC
Similarly to AHCI, introduce the device sysfs attribute
sas_ncq_prio_supported to advertize if a SATA device supports the NCQ
priority feature. Without this new attribute, the user can only
discover if a SATA device supports NCQ priority by trying to enable
the feature use with the sas_ncq_prio_enable sysfs device attribute,
which fails when the device does not support high priroity commands.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 drivers/scsi/mpt3sas/mpt3sas_ctl.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Comments

Bart Van Assche Aug. 2, 2021, 4 p.m. UTC | #1
On 8/2/21 2:02 AM, Damien Le Moal wrote:
> +/**
> + * sas_ncq_prio_supported_show - Indicate if device supports NCQ priority
> + * @dev: pointer to embedded device
> + * @attr: sas_ncq_prio_supported attribute desciptor
> + * @buf: the buffer returned
> + *
> + * A sysfs 'read/write' sdev attribute, only works with SATA
> + */
> +static ssize_t
> +sas_ncq_prio_supported_show(struct device *dev,
> +			    struct device_attribute *attr, char *buf)
> +{
> +	struct scsi_device *sdev = to_scsi_device(dev);
> +
> +	return snprintf(buf, PAGE_SIZE, "%d\n",
> +			scsih_ncq_prio_supp(sdev));
> +}
> +static DEVICE_ATTR_RO(sas_ncq_prio_supported);

Since this is new code, how about using sysfs_emit() instead of snprintf()?

Thanks,

Bart.
Damien Le Moal Aug. 2, 2021, 10:52 p.m. UTC | #2
On 2021/08/03 1:00, Bart Van Assche wrote:
> On 8/2/21 2:02 AM, Damien Le Moal wrote:
>> +/**
>> + * sas_ncq_prio_supported_show - Indicate if device supports NCQ priority
>> + * @dev: pointer to embedded device
>> + * @attr: sas_ncq_prio_supported attribute desciptor
>> + * @buf: the buffer returned
>> + *
>> + * A sysfs 'read/write' sdev attribute, only works with SATA
>> + */
>> +static ssize_t
>> +sas_ncq_prio_supported_show(struct device *dev,
>> +			    struct device_attribute *attr, char *buf)
>> +{
>> +	struct scsi_device *sdev = to_scsi_device(dev);
>> +
>> +	return snprintf(buf, PAGE_SIZE, "%d\n",
>> +			scsih_ncq_prio_supp(sdev));
>> +}
>> +static DEVICE_ATTR_RO(sas_ncq_prio_supported);
> 
> Since this is new code, how about using sysfs_emit() instead of snprintf()?

OK. Will do.

> 
> Thanks,
> 
> Bart.
>
Johannes Thumshirn Aug. 3, 2021, 7:55 a.m. UTC | #3
On 02/08/2021 11:03, Damien Le Moal wrote:
> +/**
> + * sas_ncq_prio_supported_show - Indicate if device supports NCQ priority
> + * @dev: pointer to embedded device
> + * @attr: sas_ncq_prio_supported attribute desciptor
> + * @buf: the buffer returned
> + *
> + * A sysfs 'read/write' sdev attribute, only works with SATA
> + */

[...]

> +static DEVICE_ATTR_RO(sas_ncq_prio_supported);
> +

Shouldn't that comment read: 
"A sysfs 'read only' sdev attribute, only works with SATA"
Damien Le Moal Aug. 3, 2021, 8:03 a.m. UTC | #4
On 2021/08/03 16:55, Johannes Thumshirn wrote:
> On 02/08/2021 11:03, Damien Le Moal wrote:
>> +/**
>> + * sas_ncq_prio_supported_show - Indicate if device supports NCQ priority
>> + * @dev: pointer to embedded device
>> + * @attr: sas_ncq_prio_supported attribute desciptor
>> + * @buf: the buffer returned
>> + *
>> + * A sysfs 'read/write' sdev attribute, only works with SATA
>> + */
> 
> [...]
> 
>> +static DEVICE_ATTR_RO(sas_ncq_prio_supported);
>> +
> 
> Shouldn't that comment read: 
> "A sysfs 'read only' sdev attribute, only works with SATA"

Oops. Indeed it should :)
diff mbox series

Patch

diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
index b66140e4c370..7bce8288fb4f 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_ctl.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
@@ -3918,6 +3918,25 @@  sas_device_handle_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(sas_device_handle);
 
+/**
+ * sas_ncq_prio_supported_show - Indicate if device supports NCQ priority
+ * @dev: pointer to embedded device
+ * @attr: sas_ncq_prio_supported attribute desciptor
+ * @buf: the buffer returned
+ *
+ * A sysfs 'read/write' sdev attribute, only works with SATA
+ */
+static ssize_t
+sas_ncq_prio_supported_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n",
+			scsih_ncq_prio_supp(sdev));
+}
+static DEVICE_ATTR_RO(sas_ncq_prio_supported);
+
 /**
  * sas_ncq_prio_enable_show - send prioritized io commands to device
  * @dev: pointer to embedded device
@@ -3960,6 +3979,7 @@  static DEVICE_ATTR_RW(sas_ncq_prio_enable);
 struct device_attribute *mpt3sas_dev_attrs[] = {
 	&dev_attr_sas_address,
 	&dev_attr_sas_device_handle,
+	&dev_attr_sas_ncq_prio_supported,
 	&dev_attr_sas_ncq_prio_enable,
 	NULL,
 };