rtc-ds1742: fix races around device registration

* Call dev_set_drvdata before rtc device creation
* Use devres APIs and simplify error/remove path

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 35 deletions

diff --git a/drivers/rtc/rtc-ds1742.c b/drivers/rtc/rtc-ds1742.c
index 09249459e9a..19d2f3333cf 100644
--- a/drivers/rtc/rtc-ds1742.c
+++ b/drivers/rtc/rtc-ds1742.c
@@ -21,7 +21,7 @@
 #include <linux/platform_device.h>
 #include <linux/io.h>
 
-#define DRV_VERSION "0.3"
+#define DRV_VERSION "0.4"
 
 #define RTC_SIZE                8
 
@@ -55,7 +55,6 @@ struct rtc_plat_data {
         void __iomem *ioaddr_rtc;
         size_t size_nvram;
         size_t size;
-        resource_size_t baseaddr;
         unsigned long last_jiffies;
         struct bin_attribute nvram_attr;
 };
@@ -163,27 +162,24 @@ static int __devinit ds1742_rtc_probe(struct platform_device *pdev)
         struct rtc_device *rtc;
         struct resource *res;
         unsigned int cen, sec;
-        struct rtc_plat_data *pdata = NULL;
-        void __iomem *ioaddr = NULL;
+        struct rtc_plat_data *pdata;
+        void __iomem *ioaddr;
         int ret = 0;
 
         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         if (!res)
                 return -ENODEV;
-        pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
+        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
         if (!pdata)
                 return -ENOMEM;
         pdata->size = res->end - res->start + 1;
-        if (!request_mem_region(res->start, pdata->size, pdev->name)) {
-                ret = -EBUSY;
-                goto out;
-        }
-        pdata->baseaddr = res->start;
-        ioaddr = ioremap(pdata->baseaddr, pdata->size);
-        if (!ioaddr) {
-                ret = -ENOMEM;
-                goto out;
-        }
+        if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size,
+                pdev->name))
+                return -EBUSY;
+        ioaddr = devm_ioremap(&pdev->dev, res->start, pdata->size);
+        if (!ioaddr)
+                return -ENOMEM;
+
         pdata->ioaddr_nvram = ioaddr;
         pdata->size_nvram = pdata->size - RTC_SIZE;
         pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
@@ -207,31 +203,19 @@ static int __devinit ds1742_rtc_probe(struct platform_device *pdev)
         if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 
+        pdata->last_jiffies = jiffies;
+        platform_set_drvdata(pdev, pdata);
         rtc = rtc_device_register(pdev->name, &pdev->dev,
                                   &ds1742_rtc_ops, THIS_MODULE);
-        if (IS_ERR(rtc)) {
-                ret = PTR_ERR(rtc);
-                goto out;
-        }
+        if (IS_ERR(rtc))
+                return PTR_ERR(rtc);
         pdata->rtc = rtc;
-        pdata->last_jiffies = jiffies;
-        platform_set_drvdata(pdev, pdata);
 
         ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
         if (ret) {
                 dev_err(&pdev->dev, "creating nvram file in sysfs failed\n");
-                goto out;
+                rtc_device_unregister(rtc);
         }
-
-        return 0;
- out:
-        if (pdata->rtc)
-                rtc_device_unregister(pdata->rtc);
-        if (pdata->ioaddr_nvram)
-                iounmap(pdata->ioaddr_nvram);
-        if (pdata->baseaddr)
-                release_mem_region(pdata->baseaddr, pdata->size);
-        kfree(pdata);
         return ret;
 }
 
@@ -241,9 +225,6 @@ static int __devexit ds1742_rtc_remove(struct platform_device *pdev)
 
         sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
         rtc_device_unregister(pdata->rtc);
-        iounmap(pdata->ioaddr_nvram);
-        release_mem_region(pdata->baseaddr, pdata->size);
-        kfree(pdata);
         return 0;
 }