dmaengine: idxd: Make read buffer sysfs attributes invisible for Intel IAA

In current code, the following sysfs attributes are exposed to user to
show or update the values:
  max_read_buffers (max_tokens)
  read_buffer_limit (token_limit)
  group/read_buffers_allowed (group/tokens_allowed)
  group/read_buffers_reserved (group/tokens_reserved)
  group/use_read_buffer_limit (group/use_token_limit)

>From Intel IAA spec [1], Intel IAA does not support Read Buffer
allocation control. So these sysfs attributes should not be supported on
IAA device.

Fix this issue by making these sysfs attributes invisible through
is_visible() filter when the device is IAA.

Add description in the ABI documentation to mention that these
attributes are not visible when the device does not support Read Buffer
allocation control.

[1]: https://cdrdv2.intel.com/v1/dl/getContent/721858

Fixes: fde212e44f45 ("dmaengine: idxd: deprecate token sysfs attributes for read buffers")
Fixes: c52ca478233c ("dmaengine: idxd: add configuration component of driver")
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20221022074949.11719-1-xiaochen.shen@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index f30aad90537b..7c7ec8323cb7 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -528,6 +528,22 @@ static bool idxd_group_attr_progress_limit_invisible(struct attribute *attr,
 		!idxd->hw.group_cap.progress_limit;
 }
 
+static bool idxd_group_attr_read_buffers_invisible(struct attribute *attr,
+						   struct idxd_device *idxd)
+{
+	/*
+	 * Intel IAA does not support Read Buffer allocation control,
+	 * make these attributes invisible.
+	 */
+	return (attr == &dev_attr_group_use_token_limit.attr ||
+		attr == &dev_attr_group_use_read_buffer_limit.attr ||
+		attr == &dev_attr_group_tokens_allowed.attr ||
+		attr == &dev_attr_group_read_buffers_allowed.attr ||
+		attr == &dev_attr_group_tokens_reserved.attr ||
+		attr == &dev_attr_group_read_buffers_reserved.attr) &&
+		idxd->data->type == IDXD_TYPE_IAX;
+}
+
 static umode_t idxd_group_attr_visible(struct kobject *kobj,
 				       struct attribute *attr, int n)
 {
@@ -538,6 +554,9 @@ static umode_t idxd_group_attr_visible(struct kobject *kobj,
 	if (idxd_group_attr_progress_limit_invisible(attr, idxd))
 		return 0;
 
+	if (idxd_group_attr_read_buffers_invisible(attr, idxd))
+		return 0;
+
 	return attr->mode;
 }
 
@@ -1552,6 +1571,20 @@ static bool idxd_device_attr_max_batch_size_invisible(struct attribute *attr,
 	       idxd->data->type == IDXD_TYPE_IAX;
 }
 
+static bool idxd_device_attr_read_buffers_invisible(struct attribute *attr,
+						    struct idxd_device *idxd)
+{
+	/*
+	 * Intel IAA does not support Read Buffer allocation control,
+	 * make these attributes invisible.
+	 */
+	return (attr == &dev_attr_max_tokens.attr ||
+		attr == &dev_attr_max_read_buffers.attr ||
+		attr == &dev_attr_token_limit.attr ||
+		attr == &dev_attr_read_buffer_limit.attr) &&
+		idxd->data->type == IDXD_TYPE_IAX;
+}
+
 static umode_t idxd_device_attr_visible(struct kobject *kobj,
 					struct attribute *attr, int n)
 {
@@ -1561,6 +1594,9 @@ static umode_t idxd_device_attr_visible(struct kobject *kobj,
 	if (idxd_device_attr_max_batch_size_invisible(attr, idxd))
 		return 0;
 
+	if (idxd_device_attr_read_buffers_invisible(attr, idxd))
+		return 0;
+
 	return attr->mode;
 }