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Message-Id: <200712170103.47097.rjw@sisk.pl>
Date: Mon, 17 Dec 2007 01:03:46 +0100
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Greg KH <greg@...ah.com>
Cc: Chuck Ebbert <cebbert@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Greg Kroah-Hartman <gregkh@...e.de>,
torvalds@...ux-foundation.org, linux-kernel@...r.kernel.org,
stable@...nel.org
Subject: Re: [stable] Linux 2.6.23.10
On Saturday, 15 of December 2007, Greg KH wrote:
> On Sat, Dec 15, 2007 at 03:55:40AM +0100, Rafael J. Wysocki wrote:
> > On Saturday, 15 of December 2007, Rafael J. Wysocki wrote:
> > > On Saturday, 15 of December 2007, Chuck Ebbert wrote:
> > > > On 12/14/2007 08:52 PM, Rafael J. Wysocki wrote:
> > > > > On Saturday, 15 of December 2007, Chuck Ebbert wrote:
> > > > >> On 12/14/2007 02:49 PM, Greg Kroah-Hartman wrote:
> > > > >>> Freezer: Fix APM emulation breakage
> > > > >> drivers/char/apm-emulation.c: In function 'apm_ioctl':
> > > > >> drivers/char/apm-emulation.c:370: error: implicit declaration of function 'wait_event_freezable'
> > > > >> make[2]: *** [drivers/char/apm-emulation.o] Error 1
> > > > >> make[1]: *** [drivers/char] Error 2
> > > > >
> > > > > This is my fault, sorry.
> > > > >
> > > > > I though the 2.6.24-rc fix would be suitable for 2.6.23.x, but that's not the
> > > > > case.
> > > > >
> > > > > Greg, please revert the "Freezer: Fix APM emulation breakage" patch, I'll
> > > > > prepare a separate fix suitable for -stable.
> > > > >
> > > >
> > > > It works if you add the changes to freezer.h made in commit
> > > > e42837bcd35b75bb59ae5d3e62f87be1aeeb05c3
> > >
> > > Yes, exactly, but a new patch is needed anyway.
> > >
> > > Hmm, perhaps it's better to add a new patch on top of "Freezer: Fix APM
> > > emulation breakage"? Would that be preferred?
> >
> > For convenience, below is the patch that should fix the breakage when applied
> > on top of the "Freezer: Fix APM emulation breakage" patch.
>
> Can you send me a whole new patch that works properly for the next
> 2.6.23-stable release?
Appended.
Thanks,
Rafael
---
From: Rafael J. Wysocki <rjw@...k.pl>
The APM emulation is currently broken as a result of commit
831441862956fffa17b9801db37e6ea1650b0f69
"Freezer: make kernel threads nonfreezable by default"
that removed the PF_NOFREEZE annotations from apm_ioctl() without
adding the appropriate freezer hooks. Fix it and remove the
unnecessary variable flags from apm_ioctl().
This problem has been fixed in the mainline by
commit cb43c54ca05c01533c45e4d3abfe8f99b7acf624
"Freezer: Fix APM emulation breakage".
Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
drivers/char/apm-emulation.c | 15 ++++++++-------
include/linux/freezer.h | 23 +++++++++++++++++++++++
2 files changed, 31 insertions(+), 7 deletions(-)
Index: linux-2.6.23.y/include/linux/freezer.h
===================================================================
--- linux-2.6.23.y.orig/include/linux/freezer.h
+++ linux-2.6.23.y/include/linux/freezer.h
@@ -4,6 +4,7 @@
#define FREEZER_H_INCLUDED
#include <linux/sched.h>
+#include <linux/wait.h>
#ifdef CONFIG_PM_SLEEP
/*
@@ -126,6 +127,24 @@ static inline void set_freezable(void)
current->flags &= ~PF_NOFREEZE;
}
+/*
+ * Freezer-friendly wrapper around wait_event_interruptible(), originally
+ * defined in <linux/wait.h>
+ */
+
+#define wait_event_freezable(wq, condition) \
+({ \
+ int __retval; \
+ do { \
+ __retval = wait_event_interruptible(wq, \
+ (condition) || freezing(current)); \
+ if (__retval && !freezing(current)) \
+ break; \
+ else if (!(condition)) \
+ __retval = -ERESTARTSYS; \
+ } while (try_to_freeze()); \
+ __retval; \
+})
#else /* !CONFIG_PM_SLEEP */
static inline int frozen(struct task_struct *p) { return 0; }
static inline int freezing(struct task_struct *p) { return 0; }
@@ -143,6 +162,10 @@ static inline void freezer_do_not_count(
static inline void freezer_count(void) {}
static inline int freezer_should_skip(struct task_struct *p) { return 0; }
static inline void set_freezable(void) {}
+
+#define wait_event_freezable(wq, condition) \
+ wait_event_interruptible(wq, condition)
+
#endif /* !CONFIG_PM_SLEEP */
#endif /* FREEZER_H_INCLUDED */
Index: linux-2.6.23.y/drivers/char/apm-emulation.c
===================================================================
--- linux-2.6.23.y.orig/drivers/char/apm-emulation.c
+++ linux-2.6.23.y/drivers/char/apm-emulation.c
@@ -295,7 +295,6 @@ static int
apm_ioctl(struct inode * inode, struct file *filp, u_int cmd, u_long arg)
{
struct apm_user *as = filp->private_data;
- unsigned long flags;
int err = -EINVAL;
if (!as->suser || !as->writer)
@@ -331,10 +330,16 @@ apm_ioctl(struct inode * inode, struct f
* Wait for the suspend/resume to complete. If there
* are pending acknowledges, we wait here for them.
*/
- flags = current->flags;
+ freezer_do_not_count();
wait_event(apm_suspend_waitqueue,
as->suspend_state == SUSPEND_DONE);
+
+ /*
+ * Since we are waiting until the suspend is done, the
+ * try_to_freeze() in freezer_count() will not trigger
+ */
+ freezer_count();
} else {
as->suspend_state = SUSPEND_WAIT;
mutex_unlock(&state_lock);
@@ -362,14 +367,10 @@ apm_ioctl(struct inode * inode, struct f
* Wait for the suspend/resume to complete. If there
* are pending acknowledges, we wait here for them.
*/
- flags = current->flags;
-
- wait_event_interruptible(apm_suspend_waitqueue,
+ wait_event_freezable(apm_suspend_waitqueue,
as->suspend_state == SUSPEND_DONE);
}
- current->flags = flags;
-
mutex_lock(&state_lock);
err = as->suspend_result;
as->suspend_state = SUSPEND_NONE;
--
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