[PATCH] cgroup: use assign_bit() where applicable

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@xxxxxxx>

Convert open-coded if/else with set_bit/clear_bit and their
non-atomic __set_bit/__clear_bit variants to the assign_bit/__assign_bit
API.

Done with Coccinelle semantic patch:
    // set_bit -> clear_bit => assign_bit

    @@
    expression cond, bit, addr;
    @@

    -if (cond)
    -        set_bit(bit, addr);
    -else
    -        clear_bit(bit, addr);
    +assign_bit(bit, addr, cond);

    // clear_bit -> set_bit => assign_bit

    @@
    expression cond, bit, addr;
    @@

    -if (cond)
    -        clear_bit(bit, addr);
    -else
    -        set_bit(bit, addr);
    +assign_bit(bit, addr, !cond);

    // __set_bit -> __clear_bit => __assign_bit

    @@
    expression cond, bit, addr;
    @@

    -if (cond)
    -        __set_bit(bit, addr);
    -else
    -        __clear_bit(bit, addr);
    +__assign_bit(bit, addr, cond);

    // __clear_bit -> __set_bit => __assign_bit

    @@
    expression cond, bit, addr;
    @@

    -if (cond)
    -        __clear_bit(bit, addr);
    -else
    -        __set_bit(bit, addr);
    +__assign_bit(bit, addr, !cond);

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---
 kernel/cgroup/cgroup-v1.c | 10 ++--------
 kernel/cgroup/cpuset.c    | 16 ++++------------
 kernel/cgroup/freezer.c   |  5 +----
 3 files changed, 7 insertions(+), 24 deletions(-)

diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 167bf6555a49..6825db74abf4 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -605,10 +605,7 @@ static u64 cgroup_read_notify_on_release(struct cgroup_subsys_state *css,
 static int cgroup_write_notify_on_release(struct cgroup_subsys_state *css,
 					  struct cftype *cft, u64 val)
 {
-	if (val)
-		set_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
-	else
-		clear_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
+	assign_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags, val);
 	return 0;
 }
 
@@ -621,10 +618,7 @@ static u64 cgroup_clone_children_read(struct cgroup_subsys_state *css,
 static int cgroup_clone_children_write(struct cgroup_subsys_state *css,
 				       struct cftype *cft, u64 val)
 {
-	if (val)
-		set_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
-	else
-		clear_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
+	assign_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags, val);
 	return 0;
 }
 
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 2538faac9aba..32e04bc0da64 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1216,10 +1216,7 @@ static void update_partition_sd_lb(struct cpuset *cs, int old_prs)
 	}
 	if (new_lb != !!is_sched_load_balance(cs)) {
 		rebuild_domains = true;
-		if (new_lb)
-			set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
-		else
-			clear_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
+		assign_bit(CS_SCHED_LOAD_BALANCE, &cs->flags, new_lb);
 	}
 
 	if (rebuild_domains)
@@ -2308,10 +2305,8 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
 		 */
 		if (cpuset_v2() && !is_partition_valid(cp) &&
 		    (is_sched_load_balance(parent) != is_sched_load_balance(cp))) {
-			if (is_sched_load_balance(parent))
-				set_bit(CS_SCHED_LOAD_BALANCE, &cp->flags);
-			else
-				clear_bit(CS_SCHED_LOAD_BALANCE, &cp->flags);
+			assign_bit(CS_SCHED_LOAD_BALANCE, &cp->flags,
+				   is_sched_load_balance(parent));
 		}
 
 		/*
@@ -2890,10 +2885,7 @@ int cpuset_update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
 	if (!trialcs)
 		return -ENOMEM;
 
-	if (turning_on)
-		set_bit(bit, &trialcs->flags);
-	else
-		clear_bit(bit, &trialcs->flags);
+	assign_bit(bit, &trialcs->flags, turning_on);
 
 	err = validate_change(cs, trialcs);
 	if (err < 0)
diff --git a/kernel/cgroup/freezer.c b/kernel/cgroup/freezer.c
index 6c18854bff34..35112d62318a 100644
--- a/kernel/cgroup/freezer.c
+++ b/kernel/cgroup/freezer.c
@@ -20,10 +20,7 @@ static bool cgroup_update_frozen_flag(struct cgroup *cgrp, bool frozen)
 	if (test_bit(CGRP_FROZEN, &cgrp->flags) == frozen)
 		return false;
 
-	if (frozen)
-		set_bit(CGRP_FROZEN, &cgrp->flags);
-	else
-		clear_bit(CGRP_FROZEN, &cgrp->flags);
+	assign_bit(CGRP_FROZEN, &cgrp->flags, frozen);
 
 	cgroup_file_notify(&cgrp->events_file);
 	TRACE_CGROUP_PATH(notify_frozen, cgrp, frozen);
-- 
2.51.0