Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/kcov.c b/kernel/kcov.c
index 97959d7..2ee3872 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -20,6 +20,7 @@
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/kcov.h>
+#include <linux/refcount.h>
 #include <asm/setup.h>
 
 /* Number of 64-bit words written per one comparison: */
@@ -44,7 +45,7 @@
 	 *  - opened file descriptor
 	 *  - task with enabled coverage (we can't unwire it from another task)
 	 */
-	atomic_t		refcount;
+	refcount_t		refcount;
 	/* The lock protects mode, size, area and t. */
 	spinlock_t		lock;
 	enum kcov_mode		mode;
@@ -112,7 +113,7 @@
 EXPORT_SYMBOL(__sanitizer_cov_trace_pc);
 
 #ifdef CONFIG_KCOV_ENABLE_COMPARISONS
-static void write_comp_data(u64 type, u64 arg1, u64 arg2, u64 ip)
+static void notrace write_comp_data(u64 type, u64 arg1, u64 arg2, u64 ip)
 {
 	struct task_struct *t;
 	u64 *area;
@@ -228,12 +229,12 @@
 
 static void kcov_get(struct kcov *kcov)
 {
-	atomic_inc(&kcov->refcount);
+	refcount_inc(&kcov->refcount);
 }
 
 static void kcov_put(struct kcov *kcov)
 {
-	if (atomic_dec_and_test(&kcov->refcount)) {
+	if (refcount_dec_and_test(&kcov->refcount)) {
 		vfree(kcov->area);
 		kfree(kcov);
 	}
@@ -312,7 +313,7 @@
 	if (!kcov)
 		return -ENOMEM;
 	kcov->mode = KCOV_MODE_DISABLED;
-	atomic_set(&kcov->refcount, 1);
+	refcount_set(&kcov->refcount, 1);
 	spin_lock_init(&kcov->lock);
 	filep->private_data = kcov;
 	return nonseekable_open(inode, filep);
@@ -444,10 +445,8 @@
 	 * there is no need to protect it against removal races. The
 	 * use of debugfs_create_file_unsafe() is actually safe here.
 	 */
-	if (!debugfs_create_file_unsafe("kcov", 0600, NULL, NULL, &kcov_fops)) {
-		pr_err("failed to create kcov in debugfs\n");
-		return -ENOMEM;
-	}
+	debugfs_create_file_unsafe("kcov", 0600, NULL, NULL, &kcov_fops);
+
 	return 0;
 }