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From: Shuah Khan <skhan@linuxfoundation.org>
To: gregkh@linuxfoundation.org, rafael@kernel.org, keescook@chromium.org
Cc: Shuah Khan <skhan@linuxfoundation.org>, linux-kernel@vger.kernel.org
Subject: [PATCH 03/11] drivers/base: convert deferred_trigger_count and probe_count to counter_atomic32
Date: Fri, 25 Sep 2020 17:47:17 -0600	[thread overview]
Message-ID: <2b78987b12b8eb214a46bdba0ef5cd4808c102dd.1601073127.git.skhan@linuxfoundation.org> (raw)
In-Reply-To: <cover.1601073127.git.skhan@linuxfoundation.org>

counter_atomic* is introduced to be used when a variable is used as
a simple counter and doesn't guard object lifetimes. This clearly
differentiates atomic_t usages that guard object lifetimes.

counter_atomic* variables will wrap around to 0 when it overflows and
should not be used to guard resource lifetimes, device usage and
open counts that control state changes, and pm states.

deferred_trigger_count gets incremented and read. It doesn't guard
object lifetimes, device usage counts, device open counts, and pm
states. There is very little chance of this counter overflowing.
Convert it to use counter_atomic32.

This conversion doesn't change the overflow wrap around behavior.

probe_count gets incremented, decremented, read. It doesn't guard
object lifetimes, device usage counts, device open counts, and pm
states. There is very little chance of this counter overflowing.
This counter controls the wait for known devices to complete their
probing, and probe_count == 0 ends the wait. Other than that it
meets the other criteria to be converted. Convert it to use
counter_atomic32.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
---
 drivers/base/dd.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 857b0a928e8d..cdb310aca74f 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -28,6 +28,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/pinctrl/devinfo.h>
 #include <linux/slab.h>
+#include <linux/counters.h>
 
 #include "base.h"
 #include "power/power.h"
@@ -54,7 +55,7 @@
 static DEFINE_MUTEX(deferred_probe_mutex);
 static LIST_HEAD(deferred_probe_pending_list);
 static LIST_HEAD(deferred_probe_active_list);
-static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
+static struct counter_atomic32 deferred_trigger_count = COUNTER_ATOMIC_INIT(0);
 static struct dentry *deferred_devices;
 static bool initcalls_done;
 
@@ -173,7 +174,7 @@ static void driver_deferred_probe_trigger(void)
 	 * into the active list so they can be retried by the workqueue
 	 */
 	mutex_lock(&deferred_probe_mutex);
-	atomic_inc(&deferred_trigger_count);
+	counter_atomic32_inc(&deferred_trigger_count);
 	list_splice_tail_init(&deferred_probe_pending_list,
 			      &deferred_probe_active_list);
 	mutex_unlock(&deferred_probe_mutex);
@@ -466,7 +467,7 @@ int device_bind_driver(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(device_bind_driver);
 
-static atomic_t probe_count = ATOMIC_INIT(0);
+static struct counter_atomic32 probe_count = COUNTER_ATOMIC_INIT(0);
 static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
 
 static void driver_deferred_probe_add_trigger(struct device *dev,
@@ -474,7 +475,7 @@ static void driver_deferred_probe_add_trigger(struct device *dev,
 {
 	driver_deferred_probe_add(dev);
 	/* Did a trigger occur while probing? Need to re-trigger if yes */
-	if (local_trigger_count != atomic_read(&deferred_trigger_count))
+	if (local_trigger_count != counter_atomic32_read(&deferred_trigger_count))
 		driver_deferred_probe_trigger();
 }
 
@@ -493,7 +494,7 @@ static DEVICE_ATTR_RO(state_synced);
 static int really_probe(struct device *dev, struct device_driver *drv)
 {
 	int ret = -EPROBE_DEFER;
-	int local_trigger_count = atomic_read(&deferred_trigger_count);
+	int local_trigger_count = counter_atomic32_read(&deferred_trigger_count);
 	bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
 			   !drv->suppress_bind_attrs;
 
@@ -514,7 +515,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 	if (ret)
 		return ret;
 
-	atomic_inc(&probe_count);
+	counter_atomic32_inc(&probe_count);
 	pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
 		 drv->bus->name, __func__, drv->name, dev_name(dev));
 	if (!list_empty(&dev->devres_head)) {
@@ -648,7 +649,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 	 */
 	ret = 0;
 done:
-	atomic_dec(&probe_count);
+	counter_atomic32_dec(&probe_count);
 	wake_up_all(&probe_waitqueue);
 	return ret;
 }
@@ -678,7 +679,7 @@ static int really_probe_debug(struct device *dev, struct device_driver *drv)
  */
 int driver_probe_done(void)
 {
-	int local_probe_count = atomic_read(&probe_count);
+	int local_probe_count = counter_atomic32_read(&probe_count);
 
 	pr_debug("%s: probe_count = %d\n", __func__, local_probe_count);
 	if (local_probe_count)
@@ -699,7 +700,7 @@ void wait_for_device_probe(void)
 	flush_work(&deferred_probe_work);
 
 	/* wait for the known devices to complete their probing */
-	wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
+	wait_event(probe_waitqueue, counter_atomic32_read(&probe_count) == 0);
 	async_synchronize_full();
 }
 EXPORT_SYMBOL_GPL(wait_for_device_probe);
-- 
2.25.1


  parent reply	other threads:[~2020-09-25 23:47 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-25 23:47 [PATCH 00/11] Introduce Simple atomic and non-atomic counters Shuah Khan
2020-09-25 23:47 ` Shuah Khan
2020-09-25 23:47 ` [PATCH 01/11] counters: Introduce counter_simple* and counter_atomic* counters Shuah Khan
2020-09-25 23:47 ` [PATCH 02/11] selftests:lib:test_counters: add new test for counters Shuah Khan
2020-09-25 23:47 ` Shuah Khan [this message]
2020-09-25 23:47 ` [PATCH 04/11] drivers/base/devcoredump: convert devcd_count to counter_atomic32 Shuah Khan
2020-09-25 23:47 ` [PATCH 05/11] drivers/acpi: convert seqno counter_atomic32 Shuah Khan
2020-09-25 23:47 ` [PATCH 06/11] drivers/acpi/apei: " Shuah Khan
2020-09-25 23:47 ` [PATCH 07/11] drivers/android/binder: convert stats, transaction_log to counter_atomic32 Shuah Khan
2020-09-25 23:47   ` Shuah Khan
2020-09-27 23:39   ` Joel Fernandes
2020-09-27 23:39     ` Joel Fernandes
2020-09-25 23:47 ` [PATCH 08/11] drivers/base/test/test_async_driver_probe: convert to use counter_atomic32 Shuah Khan
2020-09-25 23:47 ` [PATCH 09/11] drivers/char/ipmi: convert stats " Shuah Khan
2020-09-26  0:15   ` Corey Minyard
2020-09-26  2:05     ` Shuah Khan
2020-09-25 23:47 ` [PATCH 10/11] drivers/misc/vmw_vmci: convert num guest devices counter to counter_atomic32 Shuah Khan
2020-09-25 23:47 ` [PATCH 11/11] drivers/edac: convert pci counters " Shuah Khan
2020-09-28 12:05   ` Borislav Petkov
2020-09-25 23:52 ` [PATCH 00/11] Introduce Simple atomic and non-atomic counters Kees Cook
2020-09-25 23:52   ` Kees Cook
2020-09-26  0:13   ` Shuah Khan
2020-09-26  0:13     ` Shuah Khan
2020-09-26 16:33     ` Kees Cook
2020-09-26 16:33       ` Kees Cook
2020-09-28 22:52       ` Shuah Khan
2020-09-28 22:52         ` Shuah Khan
2020-09-26 16:22 ` Kees Cook
2020-09-26 16:22   ` Kees Cook
2020-09-28 22:42   ` Shuah Khan
2020-09-28 22:42     ` Shuah Khan
2020-09-26 16:29 ` Kees Cook
2020-09-26 16:29   ` Kees Cook
2020-09-28 22:41   ` Shuah Khan
2020-09-28 22:41     ` Shuah Khan
2020-09-28 23:13     ` Kees Cook
2020-09-28 23:13       ` Kees Cook
2020-10-06 15:21       ` Shuah Khan
2020-10-06 15:21         ` Shuah Khan
2020-09-27 23:35 ` Joel Fernandes
2020-09-27 23:35   ` Joel Fernandes
2020-09-28 20:34   ` Kees Cook
2020-09-28 20:34     ` Kees Cook
2020-09-28 21:17     ` Joel Fernandes
2020-09-28 21:17       ` Joel Fernandes
2020-09-28 23:01       ` Shuah Khan
2020-09-28 23:01         ` Shuah Khan

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