Upgrade to 4.4.50-rt62

The current kernel is based on rt kernel v4.4.6-rt14. We will upgrade it
to 4.4.50-rt62.
The command to achieve it is:
a) Clone a git repo from
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git

b) Get the diff between this two changesets:
git diff 640eca2901f3435e616157b11379d3223a44b391
705619beeea1b0b48219a683fd1a901a86fdaf5e

where the two commits are:
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
640eca2901f3435e616157b11379d3223a44b391
640eca2901f3 v4.4.6-rt14
localversion-rt
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
705619beeea1b0b48219a683fd1a901a86fdaf5e
705619beeea1 Linux 4.4.50-rt62
localversion-rt

c) One patch has been backported thus revert the patch before applying.

 filterdiff -p1 -x scripts/package/Makefile
~/tmp/v4.4.6-rt14-4.4.50-rt62.diff  |patch -p1 --dry-run

Upstream status: backport

Change-Id: I244d57a32f6066e5a5b9915f9fbf99e7bbca6e01
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>

1 files changed, 24 insertions, 9 deletions

diff --git a/kernel/drivers/hid/uhid.c b/kernel/drivers/hid/uhid.c
index e094c572b..1a2032c2c 100644
--- a/kernel/drivers/hid/uhid.c
+++ b/kernel/drivers/hid/uhid.c
@@ -51,10 +51,26 @@ struct uhid_device {
 	u32 report_id;
 	u32 report_type;
 	struct uhid_event report_buf;
+	struct work_struct worker;
 };
 
 static struct miscdevice uhid_misc;
 
+static void uhid_device_add_worker(struct work_struct *work)
+{
+	struct uhid_device *uhid = container_of(work, struct uhid_device, worker);
+	int ret;
+
+	ret = hid_add_device(uhid->hid);
+	if (ret) {
+		hid_err(uhid->hid, "Cannot register HID device: error %d\n", ret);
+
+		hid_destroy_device(uhid->hid);
+		uhid->hid = NULL;
+		uhid->running = false;
+	}
+}
+
 static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
 {
 	__u8 newhead;
@@ -498,18 +514,14 @@ static int uhid_dev_create2(struct uhid_device *uhid,
 	uhid->hid = hid;
 	uhid->running = true;
 
-	ret = hid_add_device(hid);
-	if (ret) {
-		hid_err(hid, "Cannot register HID device\n");
-		goto err_hid;
-	}
+	/* Adding of a HID device is done through a worker, to allow HID drivers
+	 * which use feature requests during .probe to work, without they would
+	 * be blocked on devlock, which is held by uhid_char_write.
+	 */
+	schedule_work(&uhid->worker);
 
 	return 0;
 
-err_hid:
-	hid_destroy_device(hid);
-	uhid->hid = NULL;
-	uhid->running = false;
 err_free:
 	kfree(uhid->rd_data);
 	uhid->rd_data = NULL;
@@ -550,6 +562,8 @@ static int uhid_dev_destroy(struct uhid_device *uhid)
 	uhid->running = false;
 	wake_up_interruptible(&uhid->report_wait);
 
+	cancel_work_sync(&uhid->worker);
+
 	hid_destroy_device(uhid->hid);
 	kfree(uhid->rd_data);
 
@@ -612,6 +626,7 @@ static int uhid_char_open(struct inode *inode, struct file *file)
 	init_waitqueue_head(&uhid->waitq);
 	init_waitqueue_head(&uhid->report_wait);
 	uhid->running = false;
+	INIT_WORK(&uhid->worker, uhid_device_add_worker);
 
 	file->private_data = uhid;
 	nonseekable_open(inode, file);