RTC: Remove the BKL.

Remove calls to the BKL since concurrent access is protected
by the spin lock rtc_lock.

Signed-off-by: David John <davidjon@xenontk.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

diff --git a/drivers/char/rtc.c b/drivers/char/rtc.c
index 20d6efb6324ef4f8dc9da36eba4c77d24df0d9cd..e0d0f8b2696b7360e39fcec6cfe25a874fe1a027 100644 (file)
--- a/drivers/char/rtc.c
+++ b/drivers/char/rtc.c
@@ -48,9 +48,10 @@
  *             CONFIG_HPET_EMULATE_RTC
  *     1.12a   Maciej W. Rozycki: Handle memory-mapped chips properly.
  *     1.12ac  Alan Cox: Allow read access to the day of week register
+ *     1.12b   David John: Remove calls to the BKL.
  */
 
-#define RTC_VERSION            "1.12ac"
+#define RTC_VERSION            "1.12b"
 
 /*
  *     Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
@@ -73,7 +74,6 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/spinlock.h>
-#include <linux/smp_lock.h>
 #include <linux/sysctl.h>
 #include <linux/wait.h>
 #include <linux/bcd.h>
@@ -182,8 +182,8 @@ static int rtc_proc_open(struct inode *inode, struct file *file);
 
 /*
  * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
- * protected by the big kernel lock. However, ioctl can still disable the timer
- * in rtc_status and then with del_timer after the interrupt has read
+ * protected by the spin lock rtc_lock. However, ioctl can still disable the
+ * timer in rtc_status and then with del_timer after the interrupt has read
  * rtc_status but before mod_timer is called, which would then reenable the
  * timer (but you would need to have an awful timing before you'd trip on it)
  */
@@ -720,9 +720,7 @@ static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, int kernel)
 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
        long ret;
-       lock_kernel();
        ret = rtc_do_ioctl(cmd, arg, 0);
-       unlock_kernel();
        return ret;
 }
 
@@ -731,12 +729,8 @@ static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  *     Also clear the previous interrupt data on an open, and clean
  *     up things on a close.
  */
-
-/* We use rtc_lock to protect against concurrent opens. So the BKL is not
- * needed here. Or anywhere else in this driver. */
 static int rtc_open(struct inode *inode, struct file *file)
 {
-       lock_kernel();
        spin_lock_irq(&rtc_lock);
 
        if (rtc_status & RTC_IS_OPEN)
@@ -746,12 +740,10 @@ static int rtc_open(struct inode *inode, struct file *file)
 
        rtc_irq_data = 0;
        spin_unlock_irq(&rtc_lock);
-       unlock_kernel();
        return 0;
 
 out_busy:
        spin_unlock_irq(&rtc_lock);
-       unlock_kernel();
        return -EBUSY;
 }
 
@@ -800,7 +792,6 @@ no_irq:
 }
 
 #ifdef RTC_IRQ
-/* Called without the kernel lock - fine */
 static unsigned int rtc_poll(struct file *file, poll_table *wait)
 {
        unsigned long l;