From 8fd37a4c9822d58c93f764864582aa13112b1513 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 30 Aug 2013 14:19:38 +0200 Subject: PM / hibernate: Create memory bitmaps after freezing user space The hibernation core uses special memory bitmaps during image creation and restoration and traditionally those bitmaps are allocated before freezing tasks, because in the past GFP_KERNEL allocations might not work after all tasks had been frozen. However, this is an anachronism, because hibernation_snapshot() now calls hibernate_preallocate_memory() which allocates memory for the image upfront anyway, so the memory bitmaps may be allocated after freezing user space safely. For this reason, move all of the create_basic_memory_bitmaps() calls after freeze_processes() and all of the corresponding free_basic_memory_bitmaps() calls before thaw_processes(). This will allow us to hold device_hotplug_lock around hibernation without the need to worry about freezing issues with user space processes attempting to acquire it via sysfs attributes after the creation of memory bitmaps and before the freezing of tasks. Signed-off-by: Rafael J. Wysocki Acked-by: Toshi Kani --- kernel/power/user.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) (limited to 'kernel/power/user.c') diff --git a/kernel/power/user.c b/kernel/power/user.c index 4ed81e74f86f..63368163e98d 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -60,11 +60,6 @@ static int snapshot_open(struct inode *inode, struct file *filp) error = -ENOSYS; goto Unlock; } - if(create_basic_memory_bitmaps()) { - atomic_inc(&snapshot_device_available); - error = -ENOMEM; - goto Unlock; - } nonseekable_open(inode, filp); data = &snapshot_state; filp->private_data = data; @@ -90,10 +85,9 @@ static int snapshot_open(struct inode *inode, struct file *filp) if (error) pm_notifier_call_chain(PM_POST_RESTORE); } - if (error) { - free_basic_memory_bitmaps(); + if (error) atomic_inc(&snapshot_device_available); - } + data->frozen = 0; data->ready = 0; data->platform_support = 0; @@ -111,11 +105,11 @@ static int snapshot_release(struct inode *inode, struct file *filp) lock_system_sleep(); swsusp_free(); - free_basic_memory_bitmaps(); data = filp->private_data; free_all_swap_pages(data->swap); if (data->frozen) { pm_restore_gfp_mask(); + free_basic_memory_bitmaps(); thaw_processes(); } pm_notifier_call_chain(data->mode == O_RDONLY ? @@ -220,14 +214,22 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, printk("done.\n"); error = freeze_processes(); - if (!error) + if (error) + break; + + error = create_basic_memory_bitmaps(); + if (error) + thaw_processes(); + else data->frozen = 1; + break; case SNAPSHOT_UNFREEZE: if (!data->frozen || data->ready) break; pm_restore_gfp_mask(); + free_basic_memory_bitmaps(); thaw_processes(); data->frozen = 0; break; -- cgit v1.2.3 From 942f40155a743f4204308d62405dacaa4bfadb11 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 30 Aug 2013 14:19:46 +0200 Subject: PM / hibernate / memory hotplug: Rework mutual exclusion Since all of the memory hotplug operations have to be carried out under device_hotplug_lock, they won't need to acquire pm_mutex if device_hotplug_lock is held around hibernation. For this reason, make the hibernation code acquire device_hotplug_lock after freezing user space processes and release it before thawing them. At the same tim drop the lock_system_sleep() and unlock_system_sleep() calls from lock_memory_hotplug() and unlock_memory_hotplug(), respectively. Signed-off-by: Rafael J. Wysocki Acked-by: Toshi Kani --- kernel/power/user.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/power/user.c') diff --git a/kernel/power/user.c b/kernel/power/user.c index 63368163e98d..72e8f4fd616d 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -201,6 +201,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, if (!mutex_trylock(&pm_mutex)) return -EBUSY; + lock_device_hotplug(); data = filp->private_data; switch (cmd) { @@ -373,6 +374,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, } + unlock_device_hotplug(); mutex_unlock(&pm_mutex); return error; -- cgit v1.2.3 From aab1728915420b5288cd0fc7b5bd320105b48983 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 30 Sep 2013 19:40:56 +0200 Subject: PM / hibernate: Fix user space driven resume regression Recent commit 8fd37a4 (PM / hibernate: Create memory bitmaps after freezing user space) broke the resume part of the user space driven hibernation (s2disk), because I forgot that the resume utility loaded the image into memory without freezing user space (it still freezes tasks after loading the image). This means that during user space driven resume we need to create the memory bitmaps at the "device open" time rather than at the "freeze tasks" time, so make that happen (that's a special case anyway, so it needs to be treated in a special way). Reported-and-tested-by: Ronald Signed-off-by: Rafael J. Wysocki --- kernel/power/user.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel/power/user.c') diff --git a/kernel/power/user.c b/kernel/power/user.c index 72e8f4fd616d..957f06164ad1 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -39,6 +39,7 @@ static struct snapshot_data { char frozen; char ready; char platform_support; + bool free_bitmaps; } snapshot_state; atomic_t snapshot_device_available = ATOMIC_INIT(1); @@ -82,6 +83,10 @@ static int snapshot_open(struct inode *inode, struct file *filp) data->swap = -1; data->mode = O_WRONLY; error = pm_notifier_call_chain(PM_RESTORE_PREPARE); + if (!error) { + error = create_basic_memory_bitmaps(); + data->free_bitmaps = !error; + } if (error) pm_notifier_call_chain(PM_POST_RESTORE); } @@ -111,6 +116,8 @@ static int snapshot_release(struct inode *inode, struct file *filp) pm_restore_gfp_mask(); free_basic_memory_bitmaps(); thaw_processes(); + } else if (data->free_bitmaps) { + free_basic_memory_bitmaps(); } pm_notifier_call_chain(data->mode == O_RDONLY ? PM_POST_HIBERNATION : PM_POST_RESTORE); @@ -231,6 +238,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, break; pm_restore_gfp_mask(); free_basic_memory_bitmaps(); + data->free_bitmaps = false; thaw_processes(); data->frozen = 0; break; -- cgit v1.2.3