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

[ Upstream commit 9a8ddb35a9d5d3ad76784a012459b256a9d7de7e ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/Documentation/ABI/stable/sysfs-driver-dma-idxd b/Documentation/ABI/stable/sysfs-driver-dma-idxd
index 69e2d91..3becc9a 100644 (file)
--- a/Documentation/ABI/stable/sysfs-driver-dma-idxd
+++ b/Documentation/ABI/stable/sysfs-driver-dma-idxd
@@ -50,6 +50,8 @@ Description:    The total number of read buffers supported by this device.
                The read buffers represent resources within the DSA
                implementation, and these resources are allocated by engines to
                support operations. See DSA spec v1.2 9.2.4 Total Read Buffers.
+               It's not visible when the device does not support Read Buffer
+               allocation control.
 
 What:           /sys/bus/dsa/devices/dsa<m>/max_transfer_size
 Date:           Oct 25, 2019
@@ -123,6 +125,8 @@ Contact:        dmaengine@vger.kernel.org
 Description:    The maximum number of read buffers that may be in use at
                one time by operations that access low bandwidth memory in the
                device. See DSA spec v1.2 9.2.8 GENCFG on Global Read Buffer Limit.
+               It's not visible when the device does not support Read Buffer
+               allocation control.
 
 What:          /sys/bus/dsa/devices/dsa<m>/cmd_status
 Date:          Aug 28, 2020
@@ -252,6 +256,8 @@ KernelVersion:      5.17.0
 Contact:       dmaengine@vger.kernel.org
 Description:   Enable the use of global read buffer limit for the group. See DSA
                spec v1.2 9.2.18 GRPCFG Use Global Read Buffer Limit.
+               It's not visible when the device does not support Read Buffer
+               allocation control.
 
 What:          /sys/bus/dsa/devices/group<m>.<n>/read_buffers_allowed
 Date:          Dec 10, 2021
@@ -260,6 +266,8 @@ Contact:    dmaengine@vger.kernel.org
 Description:   Indicates max number of read buffers that may be in use at one time
                by all engines in the group. See DSA spec v1.2 9.2.18 GRPCFG Read
                Buffers Allowed.
+               It's not visible when the device does not support Read Buffer
+               allocation control.
 
 What:          /sys/bus/dsa/devices/group<m>.<n>/read_buffers_reserved
 Date:          Dec 10, 2021
@@ -268,6 +276,8 @@ Contact:    dmaengine@vger.kernel.org
 Description:   Indicates the number of Read Buffers reserved for the use of
                engines in the group. See DSA spec v1.2 9.2.18 GRPCFG Read Buffers
                Reserved.
+               It's not visible when the device does not support Read Buffer
+               allocation control.
 
 What:          /sys/bus/dsa/devices/group<m>.<n>/desc_progress_limit
 Date:          Sept 14, 2022

diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 7909767..3229dfc 100644 (file)
--- 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;
 }