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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>
This commit is contained in:
David John 2008-10-23 13:55:56 +05:30 committed by Jonathan Corbet
parent 4a6908a3a0
commit 048cd5888f
1 changed files with 4 additions and 13 deletions
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17
drivers/char/rtc.c
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@ -48,9 +48,10 @@
* CONFIG_HPET_EMULATE_RTC * CONFIG_HPET_EMULATE_RTC
* 1.12a Maciej W. Rozycki: Handle memory-mapped chips properly. * 1.12a Maciej W. Rozycki: Handle memory-mapped chips properly.
* 1.12ac Alan Cox: Allow read access to the day of week register * 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 * Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
@ -73,7 +74,6 @@
#include <linux/proc_fs.h> #include <linux/proc_fs.h>
#include <linux/seq_file.h> #include <linux/seq_file.h>
#include <linux/spinlock.h> #include <linux/spinlock.h>
#include <linux/smp_lock.h>
#include <linux/sysctl.h> #include <linux/sysctl.h>
#include <linux/wait.h> #include <linux/wait.h>
#include <linux/bcd.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 * 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 * protected by the spin lock rtc_lock. However, ioctl can still disable the
* in rtc_status and then with del_timer after the interrupt has read * 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 * 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) * 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) static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{ {
long ret; long ret;
lock_kernel();
ret = rtc_do_ioctl(cmd, arg, 0); ret = rtc_do_ioctl(cmd, arg, 0);
unlock_kernel();
return ret; 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 * Also clear the previous interrupt data on an open, and clean
* up things on a close. * 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) static int rtc_open(struct inode *inode, struct file *file)
{ {
lock_kernel();
spin_lock_irq(&rtc_lock); spin_lock_irq(&rtc_lock);
if (rtc_status & RTC_IS_OPEN) if (rtc_status & RTC_IS_OPEN)
@ -746,12 +740,10 @@ static int rtc_open(struct inode *inode, struct file *file)
rtc_irq_data = 0; rtc_irq_data = 0;
spin_unlock_irq(&rtc_lock); spin_unlock_irq(&rtc_lock);
unlock_kernel();
return 0; return 0;
out_busy: out_busy:
spin_unlock_irq(&rtc_lock); spin_unlock_irq(&rtc_lock);
unlock_kernel();
return -EBUSY; return -EBUSY;
} }
@ -800,7 +792,6 @@ no_irq:
} }
#ifdef RTC_IRQ #ifdef RTC_IRQ
/* Called without the kernel lock - fine */
static unsigned int rtc_poll(struct file *file, poll_table *wait) static unsigned int rtc_poll(struct file *file, poll_table *wait)
{ {
unsigned long l; unsigned long l;