drop leds-trigger-use-rcu-to-protect-the-led_cdevs-list.patch

diff --git a/queue-5.14/leds-trigger-use-rcu-to-protect-the-led_cdevs-list.patch b/queue-5.14/leds-trigger-use-rcu-to-protect-the-led_cdevs-list.patch
deleted file mode 100644 (file)
index 9c7d3c0..0000000
--- a/queue-5.14/leds-trigger-use-rcu-to-protect-the-led_cdevs-list.patch
+++ /dev/null
@@ -1,165 +0,0 @@
-From 99bc2823b270cd5978a0c62bdcf79dc31b6280bc Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Wed, 15 Sep 2021 18:16:01 +0200
-Subject: leds: trigger: use RCU to protect the led_cdevs list
-
-From: Johannes Berg <johannes.berg@intel.com>
-
-[ Upstream commit 2a5a8fa8b23144d14567d6f8293dd6fbeecee393 ]
-
-Even with the previous commit 27af8e2c90fb
-("leds: trigger: fix potential deadlock with libata")
-to this file, we still get lockdep unhappy, and Boqun
-explained the report here:
-https://lore.kernel.org/r/YNA+d1X4UkoQ7g8a@boqun-archlinux
-
-Effectively, this means that the read_lock_irqsave() isn't
-enough here because another CPU might be trying to do a
-write lock, and thus block the readers.
-
-This is all pretty messy, but it doesn't seem right that
-the LEDs framework imposes some locking requirements on
-users, in particular we'd have to make the spinlock in the
-iwlwifi driver always disable IRQs, even if we don't need
-that for any other reason, just to avoid this deadlock.
-
-Since writes to the led_cdevs list are rare (and are done
-by userspace), just switch the list to RCU. This costs a
-synchronize_rcu() at removal time so we can ensure things
-are correct, but that seems like a small price to pay for
-getting lock-free iterations and no deadlocks (nor any
-locking requirements imposed on users.)
-
-Signed-off-by: Johannes Berg <johannes.berg@intel.com>
-Signed-off-by: Pavel Machek <pavel@ucw.cz>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- drivers/leds/led-triggers.c | 41 +++++++++++++++++++------------------
- include/linux/leds.h        |  2 +-
- 2 files changed, 22 insertions(+), 21 deletions(-)
-
-diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
-index 4e7b78a84149b..072491d3e17b0 100644
---- a/drivers/leds/led-triggers.c
-+++ b/drivers/leds/led-triggers.c
-@@ -157,7 +157,6 @@ EXPORT_SYMBOL_GPL(led_trigger_read);
- /* Caller must ensure led_cdev->trigger_lock held */
- int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
- {
--      unsigned long flags;
-       char *event = NULL;
-       char *envp[2];
-       const char *name;
-@@ -171,10 +170,13 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
- 
-       /* Remove any existing trigger */
-       if (led_cdev->trigger) {
--              write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
--              list_del(&led_cdev->trig_list);
--              write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
--                      flags);
-+              spin_lock(&led_cdev->trigger->leddev_list_lock);
-+              list_del_rcu(&led_cdev->trig_list);
-+              spin_unlock(&led_cdev->trigger->leddev_list_lock);
-+
-+              /* ensure it's no longer visible on the led_cdevs list */
-+              synchronize_rcu();
-+
-               cancel_work_sync(&led_cdev->set_brightness_work);
-               led_stop_software_blink(led_cdev);
-               if (led_cdev->trigger->deactivate)
-@@ -186,9 +188,9 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
-               led_set_brightness(led_cdev, LED_OFF);
-       }
-       if (trig) {
--              write_lock_irqsave(&trig->leddev_list_lock, flags);
--              list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
--              write_unlock_irqrestore(&trig->leddev_list_lock, flags);
-+              spin_lock(&trig->leddev_list_lock);
-+              list_add_tail_rcu(&led_cdev->trig_list, &trig->led_cdevs);
-+              spin_unlock(&trig->leddev_list_lock);
-               led_cdev->trigger = trig;
- 
-               if (trig->activate)
-@@ -223,9 +225,10 @@ err_add_groups:
-               trig->deactivate(led_cdev);
- err_activate:
- 
--      write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
--      list_del(&led_cdev->trig_list);
--      write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
-+      spin_lock(&led_cdev->trigger->leddev_list_lock);
-+      list_del_rcu(&led_cdev->trig_list);
-+      spin_unlock(&led_cdev->trigger->leddev_list_lock);
-+      synchronize_rcu();
-       led_cdev->trigger = NULL;
-       led_cdev->trigger_data = NULL;
-       led_set_brightness(led_cdev, LED_OFF);
-@@ -285,7 +288,7 @@ int led_trigger_register(struct led_trigger *trig)
-       struct led_classdev *led_cdev;
-       struct led_trigger *_trig;
- 
--      rwlock_init(&trig->leddev_list_lock);
-+      spin_lock_init(&trig->leddev_list_lock);
-       INIT_LIST_HEAD(&trig->led_cdevs);
- 
-       down_write(&triggers_list_lock);
-@@ -378,15 +381,14 @@ void led_trigger_event(struct led_trigger *trig,
-                       enum led_brightness brightness)
- {
-       struct led_classdev *led_cdev;
--      unsigned long flags;
- 
-       if (!trig)
-               return;
- 
--      read_lock_irqsave(&trig->leddev_list_lock, flags);
--      list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
-+      rcu_read_lock();
-+      list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list)
-               led_set_brightness(led_cdev, brightness);
--      read_unlock_irqrestore(&trig->leddev_list_lock, flags);
-+      rcu_read_unlock();
- }
- EXPORT_SYMBOL_GPL(led_trigger_event);
- 
-@@ -397,20 +399,19 @@ static void led_trigger_blink_setup(struct led_trigger *trig,
-                            int invert)
- {
-       struct led_classdev *led_cdev;
--      unsigned long flags;
- 
-       if (!trig)
-               return;
- 
--      read_lock_irqsave(&trig->leddev_list_lock, flags);
--      list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
-+      rcu_read_lock();
-+      list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {
-               if (oneshot)
-                       led_blink_set_oneshot(led_cdev, delay_on, delay_off,
-                                             invert);
-               else
-                       led_blink_set(led_cdev, delay_on, delay_off);
-       }
--      read_unlock_irqrestore(&trig->leddev_list_lock, flags);
-+      rcu_read_unlock();
- }
- 
- void led_trigger_blink(struct led_trigger *trig,
-diff --git a/include/linux/leds.h b/include/linux/leds.h
-index 329fd914cf243..fa59326b0ad9f 100644
---- a/include/linux/leds.h
-+++ b/include/linux/leds.h
-@@ -354,7 +354,7 @@ struct led_trigger {
-       struct led_hw_trigger_type *trigger_type;
- 
-       /* LEDs under control by this trigger (for simple triggers) */
--      rwlock_t          leddev_list_lock;
-+      spinlock_t        leddev_list_lock;
-       struct list_head  led_cdevs;
- 
-       /* Link to next registered trigger */
--- 
-2.33.0
-

diff --git a/queue-5.14/series b/queue-5.14/series
index 0ef71963a384f09e14f1482ffc0a0a8288908a02..0a286f66079fc071cec560408512dfa3e95b8ec4 100644 (file)
--- a/queue-5.14/series
+++ b/queue-5.14/series
@@ -228,7 +228,6 @@ fscrypt-allow-256-bit-master-keys-with-aes-256-xts.patch
 drm-amdgpu-fix-mmio-access-page-fault.patch
 drm-amd-display-fix-null-pointer-dereference-for-enc.patch
 selftests-net-fib_nexthops-wait-before-checking-repo.patch
-leds-trigger-use-rcu-to-protect-the-led_cdevs-list.patch
 ath11k-avoid-reg-rules-update-during-firmware-recove.patch
 ath11k-add-handler-for-scan-event-wmi_scan_event_deq.patch
 ath11k-change-dma_from_device-to-dma_to_device-when-.patch

diff --git a/queue-5.15/leds-trigger-use-rcu-to-protect-the-led_cdevs-list.patch b/queue-5.15/leds-trigger-use-rcu-to-protect-the-led_cdevs-list.patch
deleted file mode 100644 (file)
index c2018b7..0000000
--- a/queue-5.15/leds-trigger-use-rcu-to-protect-the-led_cdevs-list.patch
+++ /dev/null
@@ -1,165 +0,0 @@
-From 36ad1fc563c47aef0e19d9f240a428d25d6c4a56 Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Wed, 15 Sep 2021 18:16:01 +0200
-Subject: leds: trigger: use RCU to protect the led_cdevs list
-
-From: Johannes Berg <johannes.berg@intel.com>
-
-[ Upstream commit 2a5a8fa8b23144d14567d6f8293dd6fbeecee393 ]
-
-Even with the previous commit 27af8e2c90fb
-("leds: trigger: fix potential deadlock with libata")
-to this file, we still get lockdep unhappy, and Boqun
-explained the report here:
-https://lore.kernel.org/r/YNA+d1X4UkoQ7g8a@boqun-archlinux
-
-Effectively, this means that the read_lock_irqsave() isn't
-enough here because another CPU might be trying to do a
-write lock, and thus block the readers.
-
-This is all pretty messy, but it doesn't seem right that
-the LEDs framework imposes some locking requirements on
-users, in particular we'd have to make the spinlock in the
-iwlwifi driver always disable IRQs, even if we don't need
-that for any other reason, just to avoid this deadlock.
-
-Since writes to the led_cdevs list are rare (and are done
-by userspace), just switch the list to RCU. This costs a
-synchronize_rcu() at removal time so we can ensure things
-are correct, but that seems like a small price to pay for
-getting lock-free iterations and no deadlocks (nor any
-locking requirements imposed on users.)
-
-Signed-off-by: Johannes Berg <johannes.berg@intel.com>
-Signed-off-by: Pavel Machek <pavel@ucw.cz>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- drivers/leds/led-triggers.c | 41 +++++++++++++++++++------------------
- include/linux/leds.h        |  2 +-
- 2 files changed, 22 insertions(+), 21 deletions(-)
-
-diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
-index 4e7b78a84149b..072491d3e17b0 100644
---- a/drivers/leds/led-triggers.c
-+++ b/drivers/leds/led-triggers.c
-@@ -157,7 +157,6 @@ EXPORT_SYMBOL_GPL(led_trigger_read);
- /* Caller must ensure led_cdev->trigger_lock held */
- int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
- {
--      unsigned long flags;
-       char *event = NULL;
-       char *envp[2];
-       const char *name;
-@@ -171,10 +170,13 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
- 
-       /* Remove any existing trigger */
-       if (led_cdev->trigger) {
--              write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
--              list_del(&led_cdev->trig_list);
--              write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
--                      flags);
-+              spin_lock(&led_cdev->trigger->leddev_list_lock);
-+              list_del_rcu(&led_cdev->trig_list);
-+              spin_unlock(&led_cdev->trigger->leddev_list_lock);
-+
-+              /* ensure it's no longer visible on the led_cdevs list */
-+              synchronize_rcu();
-+
-               cancel_work_sync(&led_cdev->set_brightness_work);
-               led_stop_software_blink(led_cdev);
-               if (led_cdev->trigger->deactivate)
-@@ -186,9 +188,9 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
-               led_set_brightness(led_cdev, LED_OFF);
-       }
-       if (trig) {
--              write_lock_irqsave(&trig->leddev_list_lock, flags);
--              list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
--              write_unlock_irqrestore(&trig->leddev_list_lock, flags);
-+              spin_lock(&trig->leddev_list_lock);
-+              list_add_tail_rcu(&led_cdev->trig_list, &trig->led_cdevs);
-+              spin_unlock(&trig->leddev_list_lock);
-               led_cdev->trigger = trig;
- 
-               if (trig->activate)
-@@ -223,9 +225,10 @@ err_add_groups:
-               trig->deactivate(led_cdev);
- err_activate:
- 
--      write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
--      list_del(&led_cdev->trig_list);
--      write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
-+      spin_lock(&led_cdev->trigger->leddev_list_lock);
-+      list_del_rcu(&led_cdev->trig_list);
-+      spin_unlock(&led_cdev->trigger->leddev_list_lock);
-+      synchronize_rcu();
-       led_cdev->trigger = NULL;
-       led_cdev->trigger_data = NULL;
-       led_set_brightness(led_cdev, LED_OFF);
-@@ -285,7 +288,7 @@ int led_trigger_register(struct led_trigger *trig)
-       struct led_classdev *led_cdev;
-       struct led_trigger *_trig;
- 
--      rwlock_init(&trig->leddev_list_lock);
-+      spin_lock_init(&trig->leddev_list_lock);
-       INIT_LIST_HEAD(&trig->led_cdevs);
- 
-       down_write(&triggers_list_lock);
-@@ -378,15 +381,14 @@ void led_trigger_event(struct led_trigger *trig,
-                       enum led_brightness brightness)
- {
-       struct led_classdev *led_cdev;
--      unsigned long flags;
- 
-       if (!trig)
-               return;
- 
--      read_lock_irqsave(&trig->leddev_list_lock, flags);
--      list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
-+      rcu_read_lock();
-+      list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list)
-               led_set_brightness(led_cdev, brightness);
--      read_unlock_irqrestore(&trig->leddev_list_lock, flags);
-+      rcu_read_unlock();
- }
- EXPORT_SYMBOL_GPL(led_trigger_event);
- 
-@@ -397,20 +399,19 @@ static void led_trigger_blink_setup(struct led_trigger *trig,
-                            int invert)
- {
-       struct led_classdev *led_cdev;
--      unsigned long flags;
- 
-       if (!trig)
-               return;
- 
--      read_lock_irqsave(&trig->leddev_list_lock, flags);
--      list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
-+      rcu_read_lock();
-+      list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {
-               if (oneshot)
-                       led_blink_set_oneshot(led_cdev, delay_on, delay_off,
-                                             invert);
-               else
-                       led_blink_set(led_cdev, delay_on, delay_off);
-       }
--      read_unlock_irqrestore(&trig->leddev_list_lock, flags);
-+      rcu_read_unlock();
- }
- 
- void led_trigger_blink(struct led_trigger *trig,
-diff --git a/include/linux/leds.h b/include/linux/leds.h
-index a0b730be40ad2..ba4861ec73d30 100644
---- a/include/linux/leds.h
-+++ b/include/linux/leds.h
-@@ -360,7 +360,7 @@ struct led_trigger {
-       struct led_hw_trigger_type *trigger_type;
- 
-       /* LEDs under control by this trigger (for simple triggers) */
--      rwlock_t          leddev_list_lock;
-+      spinlock_t        leddev_list_lock;
-       struct list_head  led_cdevs;
- 
-       /* Link to next registered trigger */
--- 
-2.33.0
-

diff --git a/queue-5.15/series b/queue-5.15/series
index 39da0348010bd3299aace166027ed02b1f220e1e..89cf20cc55b7aaa13f16e7dedadd3c1603b09bc0 100644 (file)
--- a/queue-5.15/series
+++ b/queue-5.15/series
@@ -209,7 +209,6 @@ drm-amdgpu-fix-mmio-access-page-fault.patch
 drm-amd-display-fix-null-pointer-dereference-for-enc.patch
 crypto-api-fix-built-in-testing-dependency-failures.patch
 selftests-net-fib_nexthops-wait-before-checking-repo.patch
-leds-trigger-use-rcu-to-protect-the-led_cdevs-list.patch
 ath11k-avoid-reg-rules-update-during-firmware-recove.patch
 ath11k-add-handler-for-scan-event-wmi_scan_event_deq.patch
 ath11k-change-dma_from_device-to-dma_to_device-when-.patch