* [PATCH] cgroup: use assign_bit() where applicable
@ 2026-09-20 2:27 Peng Fan (OSS)
2026-09-21 14:13 ` Michal Koutný
2026-09-21 17:11 ` Tejun Heo
0 siblings, 2 replies; 3+ messages in thread
From: Peng Fan (OSS) @ 2026-09-20 2:27 UTC (permalink / raw)
To: Tejun Heo, Johannes Weiner, Michal Koutný, Waiman Long, Ridong Chen
Cc: linux-kernel, Peng Fan, cgroups
From: Peng Fan <peng.fan@nxp.com>
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@nxp.com>
---
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] cgroup: use assign_bit() where applicable
2026-09-20 2:27 [PATCH] cgroup: use assign_bit() where applicable Peng Fan (OSS)
@ 2026-09-21 14:13 ` Michal Koutný
2026-09-21 17:11 ` Tejun Heo
1 sibling, 0 replies; 3+ messages in thread
From: Michal Koutný @ 2026-09-21 14:13 UTC (permalink / raw)
To: Peng Fan (OSS)
Cc: Tejun Heo, Johannes Weiner, Waiman Long, Ridong Chen,
linux-kernel, Peng Fan, cgroups
On Sun, Sep 20, 2026 at 10:27:37AM +0800, "Peng Fan (OSS)" <peng.fan@oss.nxp.com> wrote:
> From: Peng Fan <peng.fan@nxp.com>
>
> 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@nxp.com>
> ---
> kernel/cgroup/cgroup-v1.c | 10 ++--------
> kernel/cgroup/cpuset.c | 16 ++++------------
> kernel/cgroup/freezer.c | 5 +----
> 3 files changed, 7 insertions(+), 24 deletions(-)
Nice use of Coccinelle,
Acked-by: Michal Koutný <mkoutny@suse.com>
(You may consider sharing an adjusted variant for
scripts/coccinelle/misc/ via cocci@inria.fr ML.)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] cgroup: use assign_bit() where applicable
2026-09-20 2:27 [PATCH] cgroup: use assign_bit() where applicable Peng Fan (OSS)
2026-09-21 14:13 ` Michal Koutný
@ 2026-09-21 17:11 ` Tejun Heo
1 sibling, 0 replies; 3+ messages in thread
From: Tejun Heo @ 2026-09-21 17:11 UTC (permalink / raw)
To: Peng Fan (OSS)
Cc: Tejun Heo, Johannes Weiner, Michal Koutný,
Waiman Long, Ridong Chen, linux-kernel, Peng Fan, cgroups
Hello,
Applied to cgroup/for-7.4.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-09-20 2:27 [PATCH] cgroup: use assign_bit() where applicable Peng Fan (OSS)
2026-09-21 14:13 ` Michal Koutný
2026-09-21 17:11 ` Tejun Heo
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