[linux-pm] [RFC][PATCH -mm] swsusp userland interface: additional ioctl

[rjw at sisk.pl (Rafael J. Wysocki)]

Hi,

The appended patch provides an additional ioctl() for the swsusp userland
interface that will allow the suspending and/or resuming utilities to change
the kernel log level at the time of suspend/resume (or even set it to 0 if
they are going to use some frame buffer graphics etc.).

Comments welcome.

Greetings,
Rafael


Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>

 kernel/power/console.c |    5 +++--
 kernel/power/power.h   |    6 +++++-
 kernel/power/user.c    |    5 +++++
 3 files changed, 13 insertions(+), 3 deletions(-)

Index: linux-2.6.16-rc1-mm3/kernel/power/console.c
===================================================================
--- linux-2.6.16-rc1-mm3.orig/kernel/power/console.c	2006-01-15 12:42:27.000000000 +0100
+++ linux-2.6.16-rc1-mm3/kernel/power/console.c	2006-01-29 21:24:48.000000000 +0100
@@ -9,7 +9,8 @@
 #include <linux/console.h>
 #include "power.h"
 
-static int new_loglevel = 10;
+int suspend_loglevel = DEFAULT_SUSPEND_LOGLEVEL;
+
 static int orig_loglevel;
 #ifdef SUSPEND_CONSOLE
 static int orig_fgconsole, orig_kmsg;
@@ -18,7 +19,7 @@ static int orig_fgconsole, orig_kmsg;
 int pm_prepare_console(void)
 {
 	orig_loglevel = console_loglevel;
-	console_loglevel = new_loglevel;
+	console_loglevel = suspend_loglevel;
 
 #ifdef SUSPEND_CONSOLE
 	acquire_console_sem();
Index: linux-2.6.16-rc1-mm3/kernel/power/power.h
===================================================================
--- linux-2.6.16-rc1-mm3.orig/kernel/power/power.h	2006-01-25 21:21:13.000000000 +0100
+++ linux-2.6.16-rc1-mm3/kernel/power/power.h	2006-01-29 21:24:58.000000000 +0100
@@ -55,6 +55,9 @@ extern struct pbe *pagedir_nosave;
 extern unsigned long image_size;
 extern int in_suspend;
 extern dev_t swsusp_resume_device;
+extern int suspend_loglevel;
+
+#define DEFAULT_SUSPEND_LOGLEVEL	10
 
 extern asmlinkage int swsusp_arch_suspend(void);
 extern asmlinkage int swsusp_arch_resume(void);
@@ -88,7 +91,8 @@ int snapshot_image_loaded(struct snapsho
 #define SNAPSHOT_GET_SWAP_PAGE		_IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
 #define SNAPSHOT_FREE_SWAP_PAGES	_IO(SNAPSHOT_IOC_MAGIC, 9)
 #define SNAPSHOT_SET_SWAP_FILE		_IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
-#define SNAPSHOT_IOC_MAXNR	10
+#define SNAPSHOT_SET_LOGLEVEL		_IOW(SNAPSHOT_IOC_MAGIC, 11, int)
+#define SNAPSHOT_IOC_MAXNR	11
 
 /**
  *	The bitmap is used for tracing allocated swap pages
Index: linux-2.6.16-rc1-mm3/kernel/power/user.c
===================================================================
--- linux-2.6.16-rc1-mm3.orig/kernel/power/user.c	2006-01-25 21:53:52.000000000 +0100
+++ linux-2.6.16-rc1-mm3/kernel/power/user.c	2006-01-29 21:24:48.000000000 +0100
@@ -78,6 +78,7 @@ static int snapshot_release(struct inode
 		enable_nonboot_cpus();
 		up(&pm_sem);
 	}
+	suspend_loglevel = DEFAULT_SUSPEND_LOGLEVEL;
 	atomic_inc(&device_available);
 	return 0;
 }
@@ -264,6 +265,10 @@ static int snapshot_ioctl(struct inode *
 		}
 		break;
 
+	case SNAPSHOT_SET_LOGLEVEL:
+		suspend_loglevel = arg <= 10 ? arg : DEFAULT_SUSPEND_LOGLEVEL;
+		break;
+
 	default:
 		error = -ENOTTY;