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Commit 58336114 authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Linus Torvalds
Browse files

markers: remove ACCESS_ONCE 



As Paul pointed out, the ACCESS_ONCE are not needed because we already have
the explicit surrounding memory barriers.

Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Mason <mmlnx@us.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: David Smith <dsmith@redhat.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Adrian Bunk <adrian.bunk@movial.fi>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fd3c36f8

kernel/marker.c

+6 −6
Original line number Original line Diff line number Diff line
@@ -109,13 +109,13 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, 
	 * modules and they insure RCU read coherency.

	 * modules and they insure RCU read coherency.

	 */

	 */

	preempt_disable();

	preempt_disable();

	ptype = ACCESS_ONCE(mdata->ptype);

	ptype = mdata->ptype;

	if (likely(!ptype)) {

	if (likely(!ptype)) {

		marker_probe_func *func;

		marker_probe_func *func;

		/* Must read the ptype before ptr. They are not data dependant,

		/* Must read the ptype before ptr. They are not data dependant,

		 * so we put an explicit smp_rmb() here. */

		 * so we put an explicit smp_rmb() here. */

		smp_rmb();

		smp_rmb();

		func = ACCESS_ONCE(mdata->single.func);

		func = mdata->single.func;

		/* Must read the ptr before private data. They are not data

		/* Must read the ptr before private data. They are not data

		 * dependant, so we put an explicit smp_rmb() here. */

		 * dependant, so we put an explicit smp_rmb() here. */

		smp_rmb();

		smp_rmb();
@@ -133,7 +133,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, 
		 * in the fast path, so put the explicit barrier here.

		 * in the fast path, so put the explicit barrier here.

		 */

		 */

		smp_read_barrier_depends();

		smp_read_barrier_depends();

		multi = ACCESS_ONCE(mdata->multi);

		multi = mdata->multi;

		for (i = 0; multi[i].func; i++) {

		for (i = 0; multi[i].func; i++) {

			va_start(args, fmt);

			va_start(args, fmt);

			multi[i].func(multi[i].probe_private, call_private, fmt,

			multi[i].func(multi[i].probe_private, call_private, fmt,
@@ -161,13 +161,13 @@ void marker_probe_cb_noarg(const struct marker *mdata, 
	char ptype;

	char ptype;





	preempt_disable();

	preempt_disable();

	ptype = ACCESS_ONCE(mdata->ptype);

	ptype = mdata->ptype;

	if (likely(!ptype)) {

	if (likely(!ptype)) {

		marker_probe_func *func;

		marker_probe_func *func;

		/* Must read the ptype before ptr. They are not data dependant,

		/* Must read the ptype before ptr. They are not data dependant,

		 * so we put an explicit smp_rmb() here. */

		 * so we put an explicit smp_rmb() here. */

		smp_rmb();

		smp_rmb();

		func = ACCESS_ONCE(mdata->single.func);

		func = mdata->single.func;

		/* Must read the ptr before private data. They are not data

		/* Must read the ptr before private data. They are not data

		 * dependant, so we put an explicit smp_rmb() here. */

		 * dependant, so we put an explicit smp_rmb() here. */

		smp_rmb();

		smp_rmb();
@@ -183,7 +183,7 @@ void marker_probe_cb_noarg(const struct marker *mdata, 
		 * in the fast path, so put the explicit barrier here.

		 * in the fast path, so put the explicit barrier here.

		 */

		 */

		smp_read_barrier_depends();

		smp_read_barrier_depends();

		multi = ACCESS_ONCE(mdata->multi);

		multi = mdata->multi;

		for (i = 0; multi[i].func; i++)

		for (i = 0; multi[i].func; i++)

			multi[i].func(multi[i].probe_private, call_private, fmt,

			multi[i].func(multi[i].probe_private, call_private, fmt,

				&args);

				&args);