HID: hid-sensor-hub: Allow parallel synchronous reads

Current implementation only allows one outstanding synchronous read.
This is a performance hit when user mode is requesting raw reads
of sensor attributes on multiple sensors together.
This change changes the mutex lock to per hid sensor hub device instead
of global lock. Although request to hid sensor hub is serialized, there
can be multiple outstanding read requests pending for responses via
hid reports.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 41 insertions, 49 deletions

diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
index 6a58b6c723aa..62fadf8c86fc 100644
--- a/drivers/hid/hid-sensor-hub.c
+++ b/drivers/hid/hid-sensor-hub.c
@@ -29,29 +29,10 @@
 #define HID_SENSOR_HUB_ENUM_QUIRK       0x01
 
 /**
- * struct sensor_hub_pending - Synchronous read pending information
- * @status:             Pending status true/false.
- * @ready:              Completion synchronization data.
- * @usage_id:           Usage id for physical device, E.g. Gyro usage id.
- * @attr_usage_id:      Usage Id of a field, E.g. X-AXIS for a gyro.
- * @raw_size:           Response size for a read request.
- * @raw_data:           Place holder for received response.
- */
-struct sensor_hub_pending {
-        bool status;
-        struct completion ready;
-        u32 usage_id;
-        u32 attr_usage_id;
-        int raw_size;
-        u8  *raw_data;
-};
-
-/**
  * struct sensor_hub_data - Hold a instance data for a HID hub device
  * @hsdev:              Stored hid instance for current hub device.
  * @mutex:              Mutex to serialize synchronous request.
  * @lock:               Spin lock to protect pending request structure.
- * @pending:            Holds information of pending sync read request.
  * @dyn_callback_list:  Holds callback function
  * @dyn_callback_lock:  spin lock to protect callback list
  * @hid_sensor_hub_client_devs: Stores all MFD cells for a hub instance.
@@ -61,7 +42,6 @@ struct sensor_hub_pending {
 struct sensor_hub_data {
         struct mutex mutex;
         spinlock_t lock;
-        struct sensor_hub_pending pending;
         struct list_head dyn_callback_list;
         spinlock_t dyn_callback_lock;
         struct mfd_cell *hid_sensor_hub_client_devs;
@@ -264,40 +244,42 @@ int sensor_hub_input_attr_get_raw_value(struct hid_sensor_hub_device *hsdev,
         struct hid_report *report;
         int ret_val = 0;
 
-        mutex_lock(&data->mutex);
-        memset(&data->pending, 0, sizeof(data->pending));
-        init_completion(&data->pending.ready);
-        data->pending.usage_id = usage_id;
-        data->pending.attr_usage_id = attr_usage_id;
-        data->pending.raw_size = 0;
+        mutex_lock(&hsdev->mutex);
+        memset(&hsdev->pending, 0, sizeof(hsdev->pending));
+        init_completion(&hsdev->pending.ready);
+        hsdev->pending.usage_id = usage_id;
+        hsdev->pending.attr_usage_id = attr_usage_id;
+        hsdev->pending.raw_size = 0;
 
         spin_lock_irqsave(&data->lock, flags);
-        data->pending.status = true;
+        hsdev->pending.status = true;
         spin_unlock_irqrestore(&data->lock, flags);
         report = sensor_hub_report(report_id, hsdev->hdev, HID_INPUT_REPORT);
         if (!report)
                 goto err_free;
 
+        mutex_lock(&data->mutex);
         hid_hw_request(hsdev->hdev, report, HID_REQ_GET_REPORT);
-        wait_for_completion_interruptible_timeout(&data->pending.ready, HZ*5);
-        switch (data->pending.raw_size) {
+        mutex_unlock(&data->mutex);
+        wait_for_completion_interruptible_timeout(&hsdev->pending.ready, HZ*5);
+        switch (hsdev->pending.raw_size) {
         case 1:
-                ret_val = *(u8 *)data->pending.raw_data;
+                ret_val = *(u8 *)hsdev->pending.raw_data;
                 break;
         case 2:
-                ret_val = *(u16 *)data->pending.raw_data;
+                ret_val = *(u16 *)hsdev->pending.raw_data;
                 break;
         case 4:
-                ret_val = *(u32 *)data->pending.raw_data;
+                ret_val = *(u32 *)hsdev->pending.raw_data;
                 break;
         default:
                 ret_val = 0;
         }
-        kfree(data->pending.raw_data);
+        kfree(hsdev->pending.raw_data);
 
 err_free:
-        data->pending.status = false;
-        mutex_unlock(&data->mutex);
+        hsdev->pending.status = false;
+        mutex_unlock(&hsdev->mutex);
 
         return ret_val;
 }
@@ -453,16 +435,6 @@ static int sensor_hub_raw_event(struct hid_device *hdev,
                                         report->field[i]->report_count)/8);
                 sz = (report->field[i]->report_size *
                                         report->field[i]->report_count)/8;
-                if (pdata->pending.status && pdata->pending.attr_usage_id ==
-                                report->field[i]->usage->hid) {
-                        hid_dbg(hdev, "data was pending ...\n");
-                        pdata->pending.raw_data = kmemdup(ptr, sz, GFP_ATOMIC);
-                        if (pdata->pending.raw_data)
-                                pdata->pending.raw_size = sz;
-                        else
-                                pdata->pending.raw_size = 0;
-                        complete(&pdata->pending.ready);
-                }
                 collection = &hdev->collection[
                                 report->field[i]->usage->collection_index];
                 hid_dbg(hdev, "collection->usage %x\n",
@@ -472,8 +444,21 @@ static int sensor_hub_raw_event(struct hid_device *hdev,
                                 report->field[i]->physical,
                                 report->field[i]->usage[0].collection_index,
                                 &hsdev, &priv);
-
-                if (callback && callback->capture_sample) {
+                if (!callback) {
+                        ptr += sz;
+                        continue;
+                }
+                if (hsdev->pending.status && hsdev->pending.attr_usage_id ==
+                                report->field[i]->usage->hid) {
+                        hid_dbg(hdev, "data was pending ...\n");
+                        hsdev->pending.raw_data = kmemdup(ptr, sz, GFP_ATOMIC);
+                        if (hsdev->pending.raw_data)
+                                hsdev->pending.raw_size = sz;
+                        else
+                                hsdev->pending.raw_size = 0;
+                        complete(&hsdev->pending.ready);
+                }
+                if (callback->capture_sample) {
                         if (report->field[i]->logical)
                                 callback->capture_sample(hsdev,
                                         report->field[i]->logical, sz, ptr,
@@ -628,6 +613,8 @@ static int sensor_hub_probe(struct hid_device *hdev,
                         hsdev->hdev = hdev;
                         hsdev->vendor_id = hdev->vendor;
                         hsdev->product_id = hdev->product;
+                        hsdev->usage = collection->usage;
+                        mutex_init(&hsdev->mutex);
                         hsdev->start_collection_index = i;
                         if (last_hsdev)
                                 last_hsdev->end_collection_index = i;
@@ -674,13 +661,18 @@ static void sensor_hub_remove(struct hid_device *hdev)
 {
         struct sensor_hub_data *data = hid_get_drvdata(hdev);
         unsigned long flags;
+        int i;
 
         hid_dbg(hdev, " hardware removed\n");
         hid_hw_close(hdev);
         hid_hw_stop(hdev);
         spin_lock_irqsave(&data->lock, flags);
-        if (data->pending.status)
-                complete(&data->pending.ready);
+        for (i = 0; i < data->hid_sensor_client_cnt; ++i) {
+                struct hid_sensor_hub_device *hsdev =
+                        data->hid_sensor_hub_client_devs[i].platform_data;
+                if (hsdev->pending.status)
+                        complete(&hsdev->pending.ready);
+        }
         spin_unlock_irqrestore(&data->lock, flags);
         mfd_remove_devices(&hdev->dev);
         hid_set_drvdata(hdev, NULL);