HID: core: allow concurrent registration of drivers

Detected on the Dell XPS 9365.

The laptop has 2 devices that benefit from the hid-generic auto-unbinding.
When those 2 devices are presented to the userspace, udev loads both wacom and
hid-multitouch. When this happens, the code in __hid_bus_reprobe_drivers() is
called concurrently and the second device gets reprobed twice.

An other bug in the power_supply subsystem prevent to remove the wacom driver
if it just finished its initialization, which basically kills the wacom node.

[jkosina@suse.cz: reformat changelog a bit]
Fixes c17a7476e4c4 ("HID: core: rewrite the hid-generic automatic unbind")
Cc: stable@vger.kernel.org # v4.17
Tested-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 6 insertions, 2 deletions

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 355dc7e49562..a460ec147aee 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1949,6 +1949,8 @@ static int hid_device_probe(struct device *dev)
         }
         hdev->io_started = false;
 
+        clear_bit(ffs(HID_STAT_REPROBED), &hdev->status);
+
         if (!hdev->driver) {
                 id = hid_match_device(hdev, hdrv);
                 if (id == NULL) {
@@ -2212,7 +2214,8 @@ static int __hid_bus_reprobe_drivers(struct device *dev, void *data)
         struct hid_device *hdev = to_hid_device(dev);
 
         if (hdev->driver == hdrv &&
-            !hdrv->match(hdev, hid_ignore_special_drivers))
+            !hdrv->match(hdev, hid_ignore_special_drivers) &&
+            !test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status))
                 return device_reprobe(dev);
 
         return 0;
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 41a3d5775394..773bcb1d4044 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -511,6 +511,7 @@ struct hid_output_fifo {
 #define HID_STAT_ADDED          BIT(0)
 #define HID_STAT_PARSED         BIT(1)
 #define HID_STAT_DUP_DETECTED   BIT(2)
+#define HID_STAT_REPROBED       BIT(3)
 
 struct hid_input {
         struct list_head list;
@@ -579,7 +580,7 @@ struct hid_device {							/* device report descriptor */
         bool battery_avoid_query;
 #endif
 
-        unsigned int status;                                            /* see STAT flags above */
+        unsigned long status;                                           /* see STAT flags above */
         unsigned claimed;                                               /* Claimed by hidinput, hiddev? */
         unsigned quirks;                                                /* Various quirks the device can pull on us */
         bool io_started;                                                /* If IO has started */