linux-kernel - [PATCH v2 2/3] driver core: Read atomic counter once in driver_probe

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Message-Id: <20200324122023.9649-2-andriy.shevchenko@linux.intel.com>
Date:   Tue, 24 Mar 2020 14:20:22 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org,
        "Rafael J. Wysocki" <rafael@...nel.org>, linux-pm@...r.kernel.org
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Ferry Toth <fntoth@...il.com>
Subject: [PATCH v2 2/3] driver core: Read atomic counter once in driver_probe_done()

Between printing the debug message and actual check atomic counter can be
altered. For better debugging experience read atomic counter value only once.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Tested-by: Ferry Toth <fntoth@...il.com>
---
v2: picked up tags
 drivers/base/dd.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 43720beb5300..efd0e4c16ba5 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -669,9 +669,10 @@ static int really_probe_debug(struct device *dev, struct device_driver *drv)
  */
 int driver_probe_done(void)
 {
-	pr_debug("%s: probe_count = %d\n", __func__,
-		 atomic_read(&probe_count));
-	if (atomic_read(&probe_count))
+	int local_probe_count = atomic_read(&probe_count);
+
+	pr_debug("%s: probe_count = %d\n", __func__, local_probe_count);
+	if (local_probe_count)
 		return -EBUSY;
 	return 0;
 }
-- 
2.25.1