vdso/gettimeofday: Clarify comment about open coded function

The two comments state, that the following code open codes something but
they lack to specify what exactly is open coded.

Expand comments by mentioning the reference to the open coded function.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/r/20240701-vdso-cleanup-v1-1-36eb64e7ece2@linutronix.de

lib/vdso/gettimeofday.c

@@ -140,14 +140,14 @@ static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk,
 
 	do {
 		/*
-		 * Open coded to handle VDSO_CLOCKMODE_TIMENS. Time namespace
-		 * enabled tasks have a special VVAR page installed which
-		 * has vd->seq set to 1 and vd->clock_mode set to
-		 * VDSO_CLOCKMODE_TIMENS. For non time namespace affected tasks
-		 * this does not affect performance because if vd->seq is
-		 * odd, i.e. a concurrent update is in progress the extra
-		 * check for vd->clock_mode is just a few extra
-		 * instructions while spin waiting for vd->seq to become
+		 * Open coded function vdso_read_begin() to handle
+		 * VDSO_CLOCKMODE_TIMENS. Time namespace enabled tasks have a
+		 * special VVAR page installed which has vd->seq set to 1 and
+		 * vd->clock_mode set to VDSO_CLOCKMODE_TIMENS. For non time
+		 * namespace affected tasks this does not affect performance
+		 * because if vd->seq is odd, i.e. a concurrent update is in
+		 * progress the extra check for vd->clock_mode is just a few
+		 * extra instructions while spin waiting for vd->seq to become
 		 * even again.
 		 */
 		while (unlikely((seq = READ_ONCE(vd->seq)) & 1)) {
@@ -223,8 +223,8 @@ static __always_inline int do_coarse(const struct vdso_data *vd, clockid_t clk,
 
 	do {
 		/*
-		 * Open coded to handle VDSO_CLOCK_TIMENS. See comment in
-		 * do_hres().
+		 * Open coded function vdso_read_begin() to handle
+		 * VDSO_CLOCK_TIMENS. See comment in do_hres().
 		 */
 		while ((seq = READ_ONCE(vd->seq)) & 1) {
 			if (IS_ENABLED(CONFIG_TIME_NS) &&