RE: [PATCH v2 4/4] drivers: hv: mark channel attributes as const

[Michael Kelley]

From: Thomas Weißschuh <linux@xxxxxxxxxxxxxx> Sent: Friday, April 3, 2026 1:29 AM
> 
> These attributes are never modified, mark them as const.
> 
> Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
> Tested-by: Michael Kelley <mhklinux@xxxxxxxxxxx>

Reviewed-by: Michael Kelley <mhklinux@xxxxxxxxxxx>

But take a look at this analysis from Sashiko AI:
https://sashiko.dev/#/patchset/20260403-sysfs-const-hv-v2-0-8932ab8d41db%40weissschuh.net

This seems to be a valid concern with your earlier commit 7dd9fdb4939b9
"sysfs: attribute_group: enable const variants of is_visible()".

> ---
>  drivers/hv/vmbus_drv.c | 38 +++++++++++++++++++-------------------
>  1 file changed, 19 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index ecce6b72a2a2..b33b85764c19 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -1695,7 +1695,7 @@ static ssize_t out_mask_show(struct vmbus_channel
> *channel, char *buf)
>  	mutex_unlock(&rbi->ring_buffer_mutex);
>  	return ret;
>  }
> -static VMBUS_CHAN_ATTR_RO(out_mask);
> +static const VMBUS_CHAN_ATTR_RO(out_mask);
> 
>  static ssize_t in_mask_show(struct vmbus_channel *channel, char *buf)
>  {
> @@ -1712,7 +1712,7 @@ static ssize_t in_mask_show(struct vmbus_channel
> *channel, char *buf)
>  	mutex_unlock(&rbi->ring_buffer_mutex);
>  	return ret;
>  }
> -static VMBUS_CHAN_ATTR_RO(in_mask);
> +static const VMBUS_CHAN_ATTR_RO(in_mask);
> 
>  static ssize_t read_avail_show(struct vmbus_channel *channel, char *buf)
>  {
> @@ -1729,7 +1729,7 @@ static ssize_t read_avail_show(struct vmbus_channel
> *channel, char *buf)
>  	mutex_unlock(&rbi->ring_buffer_mutex);
>  	return ret;
>  }
> -static VMBUS_CHAN_ATTR_RO(read_avail);
> +static const VMBUS_CHAN_ATTR_RO(read_avail);
> 
>  static ssize_t write_avail_show(struct vmbus_channel *channel, char *buf)
>  {
> @@ -1746,7 +1746,7 @@ static ssize_t write_avail_show(struct vmbus_channel
> *channel, char *buf)
>  	mutex_unlock(&rbi->ring_buffer_mutex);
>  	return ret;
>  }
> -static VMBUS_CHAN_ATTR_RO(write_avail);
> +static const VMBUS_CHAN_ATTR_RO(write_avail);
> 
>  static ssize_t target_cpu_show(struct vmbus_channel *channel, char *buf)
>  {
> @@ -1864,7 +1864,7 @@ static ssize_t target_cpu_store(struct vmbus_channel
> *channel,
> 
>  	return ret ?: count;
>  }
> -static VMBUS_CHAN_ATTR(cpu, 0644, target_cpu_show, target_cpu_store);
> +static const VMBUS_CHAN_ATTR(cpu, 0644, target_cpu_show, target_cpu_store);
> 
>  static ssize_t channel_pending_show(struct vmbus_channel *channel,
>  				    char *buf)
> @@ -1873,7 +1873,7 @@ static ssize_t channel_pending_show(struct vmbus_channel
> *channel,
>  		       channel_pending(channel,
>  				       vmbus_connection.monitor_pages[1]));
>  }
> -static VMBUS_CHAN_ATTR(pending, 0444, channel_pending_show, NULL);
> +static const VMBUS_CHAN_ATTR(pending, 0444, channel_pending_show, NULL);
> 
>  static ssize_t channel_latency_show(struct vmbus_channel *channel,
>  				    char *buf)
> @@ -1882,19 +1882,19 @@ static ssize_t channel_latency_show(struct
> vmbus_channel *channel,
>  		       channel_latency(channel,
>  				       vmbus_connection.monitor_pages[1]));
>  }
> -static VMBUS_CHAN_ATTR(latency, 0444, channel_latency_show, NULL);
> +static const VMBUS_CHAN_ATTR(latency, 0444, channel_latency_show, NULL);
> 
>  static ssize_t channel_interrupts_show(struct vmbus_channel *channel, char *buf)
>  {
>  	return sprintf(buf, "%llu\n", channel->interrupts);
>  }
> -static VMBUS_CHAN_ATTR(interrupts, 0444, channel_interrupts_show, NULL);
> +static const VMBUS_CHAN_ATTR(interrupts, 0444, channel_interrupts_show, NULL);
> 
>  static ssize_t channel_events_show(struct vmbus_channel *channel, char *buf)
>  {
>  	return sprintf(buf, "%llu\n", channel->sig_events);
>  }
> -static VMBUS_CHAN_ATTR(events, 0444, channel_events_show, NULL);
> +static const VMBUS_CHAN_ATTR(events, 0444, channel_events_show, NULL);
> 
>  static ssize_t channel_intr_in_full_show(struct vmbus_channel *channel,
>  					 char *buf)
> @@ -1902,7 +1902,7 @@ static ssize_t channel_intr_in_full_show(struct
> vmbus_channel *channel,
>  	return sprintf(buf, "%llu\n",
>  		       (unsigned long long)channel->intr_in_full);
>  }
> -static VMBUS_CHAN_ATTR(intr_in_full, 0444, channel_intr_in_full_show, NULL);
> +static const VMBUS_CHAN_ATTR(intr_in_full, 0444, channel_intr_in_full_show, NULL);
> 
>  static ssize_t channel_intr_out_empty_show(struct vmbus_channel *channel,
>  					   char *buf)
> @@ -1910,7 +1910,7 @@ static ssize_t channel_intr_out_empty_show(struct
> vmbus_channel *channel,
>  	return sprintf(buf, "%llu\n",
>  		       (unsigned long long)channel->intr_out_empty);
>  }
> -static VMBUS_CHAN_ATTR(intr_out_empty, 0444, channel_intr_out_empty_show,
> NULL);
> +static const VMBUS_CHAN_ATTR(intr_out_empty, 0444,
> channel_intr_out_empty_show, NULL);
> 
>  static ssize_t channel_out_full_first_show(struct vmbus_channel *channel,
>  					   char *buf)
> @@ -1918,7 +1918,7 @@ static ssize_t channel_out_full_first_show(struct
> vmbus_channel *channel,
>  	return sprintf(buf, "%llu\n",
>  		       (unsigned long long)channel->out_full_first);
>  }
> -static VMBUS_CHAN_ATTR(out_full_first, 0444, channel_out_full_first_show, NULL);
> +static const VMBUS_CHAN_ATTR(out_full_first, 0444, channel_out_full_first_show,
> NULL);
> 
>  static ssize_t channel_out_full_total_show(struct vmbus_channel *channel,
>  					   char *buf)
> @@ -1926,14 +1926,14 @@ static ssize_t channel_out_full_total_show(struct
> vmbus_channel *channel,
>  	return sprintf(buf, "%llu\n",
>  		       (unsigned long long)channel->out_full_total);
>  }
> -static VMBUS_CHAN_ATTR(out_full_total, 0444, channel_out_full_total_show, NULL);
> +static const VMBUS_CHAN_ATTR(out_full_total, 0444, channel_out_full_total_show,
> NULL);
> 
>  static ssize_t subchannel_monitor_id_show(struct vmbus_channel *channel,
>  					  char *buf)
>  {
>  	return sprintf(buf, "%u\n", channel->offermsg.monitorid);
>  }
> -static VMBUS_CHAN_ATTR(monitor_id, 0444, subchannel_monitor_id_show, NULL);
> +static const VMBUS_CHAN_ATTR(monitor_id, 0444, subchannel_monitor_id_show,
> NULL);
> 
>  static ssize_t subchannel_id_show(struct vmbus_channel *channel,
>  				  char *buf)
> @@ -1941,7 +1941,7 @@ static ssize_t subchannel_id_show(struct vmbus_channel
> *channel,
>  	return sprintf(buf, "%u\n",
>  		       channel->offermsg.offer.sub_channel_index);
>  }
> -static VMBUS_CHAN_ATTR_RO(subchannel_id);
> +static const VMBUS_CHAN_ATTR_RO(subchannel_id);
> 
>  static int hv_mmap_ring_buffer_wrapper(struct file *filp, struct kobject *kobj,
>  				       const struct bin_attribute *attr,
> @@ -1963,7 +1963,7 @@ static const struct bin_attribute chan_attr_ring_buffer = {
>  	},
>  	.mmap = hv_mmap_ring_buffer_wrapper,
>  };
> -static struct attribute *vmbus_chan_attrs[] = {
> +static const struct attribute *const vmbus_chan_attrs[] = {
>  	&chan_attr_out_mask.attr,
>  	&chan_attr_in_mask.attr,
>  	&chan_attr_read_avail.attr,
> @@ -1992,7 +1992,7 @@ static const struct bin_attribute *const
> vmbus_chan_bin_attrs[] = {
>   * each attribute, and returns 0 if an attribute is not visible.
>   */
>  static umode_t vmbus_chan_attr_is_visible(struct kobject *kobj,
> -					  struct attribute *attr, int idx)
> +					  const struct attribute *attr, int idx)
>  {
>  	const struct vmbus_channel *channel =
>  		container_of(kobj, struct vmbus_channel, kobj);
> @@ -2030,9 +2030,9 @@ static size_t vmbus_chan_bin_size(struct kobject *kobj,
>  }
> 
>  static const struct attribute_group vmbus_chan_group = {
> -	.attrs = vmbus_chan_attrs,
> +	.attrs_const = vmbus_chan_attrs,
>  	.bin_attrs = vmbus_chan_bin_attrs,
> -	.is_visible = vmbus_chan_attr_is_visible,
> +	.is_visible_const = vmbus_chan_attr_is_visible,
>  	.is_bin_visible = vmbus_chan_bin_attr_is_visible,
>  	.bin_size = vmbus_chan_bin_size,
>  };
> 
> --
> 2.53.0
>