Messages in this thread Patch in this message | | | Date | Thu, 15 Oct 2009 08:42:21 -0000 | From | Thomas Gleixner <> | Subject | [patch 2/7] m68k: Remove BKL from rtc implementations |
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m68k does not support SMP. The access to the rtc is already serialized with local_irq_save/restore which is sufficient on UP.
The open() protection in arch/m68k/mvme16x/rtc.c is not pretty but sufficient on UP and safe w/o the BKL.
open() in arch/m68k/bvme6000/rtc.c can do with the same atomic logic as arch/m68k/mvme16x/rtc.c
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Geert Uytterhoeven <geert@linux-m68k.org> --- arch/m68k/bvme6000/rtc.c | 29 +++++++++-------------------- arch/m68k/mvme16x/rtc.c | 19 +++++-------------- 2 files changed, 14 insertions(+), 34 deletions(-)
Index: linux-2.6-tip/arch/m68k/bvme6000/rtc.c =================================================================== --- linux-2.6-tip.orig/arch/m68k/bvme6000/rtc.c +++ linux-2.6-tip/arch/m68k/bvme6000/rtc.c @@ -10,7 +10,6 @@ #include <linux/errno.h> #include <linux/miscdevice.h> #include <linux/slab.h> -#include <linux/smp_lock.h> #include <linux/ioport.h> #include <linux/capability.h> #include <linux/fcntl.h> @@ -36,10 +35,9 @@ static unsigned char days_in_mo[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; -static char rtc_status; +static atomic_t rtc_status = ATOMIC_INIT(1); -static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, - unsigned long arg) +static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE; unsigned char msr; @@ -133,29 +131,20 @@ static int rtc_ioctl(struct inode *inode } /* - * We enforce only one user at a time here with the open/close. - * Also clear the previous interrupt data on an open, and clean - * up things on a close. + * We enforce only one user at a time here with the open/close. */ - static int rtc_open(struct inode *inode, struct file *file) { - lock_kernel(); - if(rtc_status) { - unlock_kernel(); + if (!atomic_dec_and_test(&rtc_status)) { + atomic_inc(&rtc_status); return -EBUSY; } - - rtc_status = 1; - unlock_kernel(); return 0; } static int rtc_release(struct inode *inode, struct file *file) { - lock_kernel(); - rtc_status = 0; - unlock_kernel(); + atomic_inc(&rtc_status); return 0; } @@ -164,9 +153,9 @@ static int rtc_release(struct inode *ino */ static const struct file_operations rtc_fops = { - .ioctl = rtc_ioctl, - .open = rtc_open, - .release = rtc_release, + .unlocked_ioctl = rtc_ioctl, + .open = rtc_open, + .release = rtc_release, }; static struct miscdevice rtc_dev = { Index: linux-2.6-tip/arch/m68k/mvme16x/rtc.c =================================================================== --- linux-2.6-tip.orig/arch/m68k/mvme16x/rtc.c +++ linux-2.6-tip/arch/m68k/mvme16x/rtc.c @@ -10,7 +10,6 @@ #include <linux/errno.h> #include <linux/miscdevice.h> #include <linux/slab.h> -#include <linux/smp_lock.h> #include <linux/ioport.h> #include <linux/capability.h> #include <linux/fcntl.h> @@ -37,8 +36,7 @@ static const unsigned char days_in_mo[] static atomic_t rtc_ready = ATOMIC_INIT(1); -static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, - unsigned long arg) +static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { volatile MK48T08ptr_t rtc = (MK48T08ptr_t)MVME_RTC_BASE; unsigned long flags; @@ -121,22 +119,15 @@ static int rtc_ioctl(struct inode *inode } /* - * We enforce only one user at a time here with the open/close. - * Also clear the previous interrupt data on an open, and clean - * up things on a close. + * We enforce only one user at a time here with the open/close. */ - static int rtc_open(struct inode *inode, struct file *file) { - lock_kernel(); if( !atomic_dec_and_test(&rtc_ready) ) { atomic_inc( &rtc_ready ); - unlock_kernel(); return -EBUSY; } - unlock_kernel(); - return 0; } @@ -151,9 +142,9 @@ static int rtc_release(struct inode *ino */ static const struct file_operations rtc_fops = { - .ioctl = rtc_ioctl, - .open = rtc_open, - .release = rtc_release, + .unlocked_ioctl = rtc_ioctl, + .open = rtc_open, + .release = rtc_release, }; static struct miscdevice rtc_dev=
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