[PATCH 5/5] swsusp: Use GFP_KERNEL for creating basic data structures

Rafael J. Wysocki
2007-03-20T21:27:00Z

From: Rafael J. Wysocki <rjw@sisk.pl>

Make swsusp call create_basic_memory_bitmaps() before processes are frozen,
so that GFP_KERNEL allocations can be made in it. Additionally, ensure
that the swsusp's userland interface won't be used while either
pm_suspend_disk() or software_resume() is being executed.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
kernel/power/disk.c | 37 ++++++++++++++++++++++++++-----------
kernel/power/power.h | 3 +++
kernel/power/snapshot.c | 8 ++++----
kernel/power/user.c | 10 +++++-----
4 files changed, 38 insertions(+), 20 deletions(-)

Index: linux-2.6.21-rc4-mm1/kernel/power/disk.c
===================================================================
--- linux-2.6.21-rc4-mm1.orig/kernel/power/disk.c 2007-03-20 21:35:59.000000000 +0100
+++ linux-2.6.21-rc4-mm1/kernel/power/disk.c 2007-03-20 21:36:03.000000000 +0100
@@ -119,28 +119,33 @@ int pm_suspend_disk(void)
{
int error;

+ /* The snapshot device should not be opened while we're running */
+ if (!atomic_add_unless(&snapshot_device_available, -1, 0))
+ return -EBUSY;
+
+ /* Allocate memory management structures */
+ error = create_basic_memory_bitmaps();
+ if (error)
+ goto Exit;
+
error = prepare_processes();
if (error)
- return error;
+ goto Finish;

if (pm_disk_mode == PM_DISK_TESTPROC) {
printk("swsusp debug: Waiting for 5 seconds.\n");
mdelay(5000);
goto Thaw;
}
- /* Allocate memory management structures */
- error = create_basic_memory_bitmaps();
- if (error)
- goto Thaw;

/* Free memory before shutting down devices. */
error = swsusp_shrink_memory();
if (error)
- goto Finish;
+ goto Thaw;

error = platform_prepare();
if (error)
- goto Finish;
+ goto Thaw;

suspend_console();
error = device_suspend(PMSG_FREEZE);
@@ -175,7 +180,7 @@ int pm_suspend_disk(void)
power_down(pm_disk_mode);
else {
swsusp_free();
- goto Finish;
+ goto Thaw;
}
} else {
pr_debug("PM: Image restored successfully.\n");
@@ -188,10 +193,12 @@ int pm_suspend_disk(void)
platform_finish();
device_resume();
resume_console();
- Finish:
- free_basic_memory_bitmaps();
Thaw:
unprepare_processes();
+ Finish:
+ free_basic_memory_bitmaps();
+ Exit:
+ atomic_inc(&snapshot_device_available);
return error;
}

@@ -239,9 +246,15 @@ static int software_resume(void)
if (error)
goto Unlock;

+ /* The snapshot device should not be opened while we're running */
+ if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
+ error = -EBUSY;
+ goto Unlock;
+ }
+
error = create_basic_memory_bitmaps();
if (error)
- goto Unlock;
+ goto Finish;

pr_debug("PM: Preparing processes for restore.\n");
error = prepare_processes();
@@ -288,6 +301,8 @@ static int software_resume(void)
unprepare_processes();
Done:
free_basic_memory_bitmaps();
+ Finish:
+ atomic_inc(&snapshot_device_available);
/* For success case, the suspend path will release the lock */
Unlock:
mutex_unlock(&pm_mutex);
Index: linux-2.6.21-rc4-mm1/kernel/power/power.h
===================================================================
--- linux-2.6.21-rc4-mm1.orig/kernel/power/power.h 2007-03-20 21:35:59.000000000 +0100
+++ linux-2.6.21-rc4-mm1/kernel/power/power.h 2007-03-20 21:36:03.000000000 +0100
@@ -141,6 +141,9 @@ struct resume_swap_area {
#define PMOPS_ENTER 2
#define PMOPS_FINISH 3

+/* If unset, the snapshot device cannot be open. */
+extern atomic_t snapshot_device_available;
+
/**
* The bitmap is used for tracing allocated swap pages
*
Index: linux-2.6.21-rc4-mm1/kernel/power/snapshot.c
===================================================================
--- linux-2.6.21-rc4-mm1.orig/kernel/power/snapshot.c 2007-03-20 21:35:59.000000000 +0100
+++ linux-2.6.21-rc4-mm1/kernel/power/snapshot.c 2007-03-20 21:36:03.000000000 +0100
@@ -723,19 +723,19 @@ int create_basic_memory_bitmaps(void)

BUG_ON(forbidden_pages_map || free_pages_map);

- bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_ATOMIC);
+ bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
if (!bm1)
return -ENOMEM;

- error = memory_bm_create(bm1, GFP_ATOMIC | __GFP_COLD, PG_ANY);
+ error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
if (error)
goto Free_first_object;

- bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_ATOMIC);
+ bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
if (!bm2)
goto Free_first_bitmap;

- error = memory_bm_create(bm2, GFP_ATOMIC | __GFP_COLD, PG_ANY);
+ error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
if (error)
goto Free_second_object;

Index: linux-2.6.21-rc4-mm1/kernel/power/user.c
===================================================================
--- linux-2.6.21-rc4-mm1.orig/kernel/power/user.c 2007-03-20 21:35:59.000000000 +0100
+++ linux-2.6.21-rc4-mm1/kernel/power/user.c 2007-03-20 21:36:03.000000000 +0100
@@ -40,21 +40,21 @@ static struct snapshot_data {
char platform_suspend;
} snapshot_state;

-static atomic_t device_available = ATOMIC_INIT(1);
+atomic_t snapshot_device_available = ATOMIC_INIT(1);

static int snapshot_open(struct inode *inode, struct file *filp)
{
struct snapshot_data *data;

- if (!atomic_add_unless(&device_available, -1, 0))
+ if (!atomic_add_unless(&snapshot_device_available, -1, 0))
return -EBUSY;

if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
- atomic_inc(&device_available);
+ atomic_inc(&snapshot_device_available);
return -ENOSYS;
}
if(create_basic_memory_bitmaps()) {
- atomic_inc(&device_available);
+ atomic_inc(&snapshot_device_available);
return -ENOMEM;
}
nonseekable_open(inode, filp);
@@ -92,7 +92,7 @@ static int snapshot_release(struct inode
enable_nonboot_cpus();
mutex_unlock(&pm_mutex);
}
- atomic_inc(&device_available);
+ atomic_inc(&snapshot_device_available);
return 0;
}