linux-kernel - [tip: timers/urgent] timers/migration: Read childmask and parent pointer in a single place

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Message-ID: <172167691924.2215.2710732679471029604.tip-bot2@tip-bot2>
Date: Mon, 22 Jul 2024 19:35:19 -0000
From: "tip-bot2 for Anna-Maria Behnsen" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: "Anna-Maria Behnsen" <anna-maria@...utronix.de>,
 Thomas Gleixner <tglx@...utronix.de>,
 Frederic Weisbecker <frederic@...nel.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: timers/urgent] timers/migration: Read childmask and parent
 pointer in a single place

The following commit has been merged into the timers/urgent branch of tip:

Commit-ID:     d47be589844224a3ef13b55ff6f15211ab20f1d1
Gitweb:        https://git.kernel.org/tip/d47be589844224a3ef13b55ff6f15211ab20f1d1
Author:        Anna-Maria Behnsen <anna-maria@...utronix.de>
AuthorDate:    Tue, 16 Jul 2024 16:19:23 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Mon, 22 Jul 2024 18:03:34 +02:00

timers/migration: Read childmask and parent pointer in a single place

Reading the childmask and parent pointer is required when propagating
changes through the hierarchy. At the moment this reads are spread all over
the place which makes it harder to follow.

Move those reads to a single place to keep code clean.

Signed-off-by: Anna-Maria Behnsen <anna-maria@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Frederic Weisbecker <frederic@...nel.org>
Link: https://lore.kernel.org/r/20240716-tmigr-fixes-v4-5-757baa7803fe@linutronix.de

---
 kernel/time/timer_migration.c | 20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/kernel/time/timer_migration.c b/kernel/time/timer_migration.c
index 9f0c284..f5652b0 100644
--- a/kernel/time/timer_migration.c
+++ b/kernel/time/timer_migration.c
@@ -535,6 +535,7 @@ static void __walk_groups(up_f up, struct tmigr_walk *data,
 
 		child = group;
 		group = group->parent;
+		data->childmask = child->childmask;
 	} while (group);
 }
 
@@ -647,9 +648,6 @@ static bool tmigr_active_up(struct tmigr_group *group,
 
 	trace_tmigr_group_set_cpu_active(group, newstate, childmask);
 
-	if (walk_done == false)
-		data->childmask = group->childmask;
-
 	/*
 	 * The group is active (again). The group event might be still queued
 	 * into the parent group's timerqueue but can now be handled by the
@@ -1027,12 +1025,10 @@ again:
 	}
 
 	/*
-	 * Update of childmask for the next level and keep track of the expiry
-	 * of the first event that needs to be handled (group->next_expiry was
-	 * updated by tmigr_next_expired_groupevt(), next was set by
-	 * tmigr_handle_remote_cpu()).
+	 * Keep track of the expiry of the first event that needs to be handled
+	 * (group->next_expiry was updated by tmigr_next_expired_groupevt(),
+	 * next was set by tmigr_handle_remote_cpu()).
 	 */
-	data->childmask = group->childmask;
 	data->firstexp = group->next_expiry;
 
 	raw_spin_unlock_irq(&group->lock);
@@ -1110,7 +1106,7 @@ static bool tmigr_requires_handle_remote_up(struct tmigr_group *group,
 	 * group before reading the next_expiry value.
 	 */
 	if (group->parent && !data->tmc_active)
-		goto out;
+		return false;
 
 	/*
 	 * The lock is required on 32bit architectures to read the variable
@@ -1135,9 +1131,6 @@ static bool tmigr_requires_handle_remote_up(struct tmigr_group *group,
 		raw_spin_unlock(&group->lock);
 	}
 
-out:
-	/* Update of childmask for the next level */
-	data->childmask = group->childmask;
 	return false;
 }
 
@@ -1309,9 +1302,6 @@ static bool tmigr_inactive_up(struct tmigr_group *group,
 	/* Event Handling */
 	tmigr_update_events(group, child, data);
 
-	if (walk_done == false)
-		data->childmask = group->childmask;
-
 	return walk_done;
 }