* 'pm-freezer' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc: (24 commits)
freezer: fix wait_event_freezable/__thaw_task races
freezer: kill unused set_freezable_with_signal()
dmatest: don't use set_freezable_with_signal()
usb_storage: don't use set_freezable_with_signal()
freezer: remove unused @sig_only from freeze_task()
freezer: use lock_task_sighand() in fake_signal_wake_up()
freezer: restructure __refrigerator()
freezer: fix set_freezable[_with_signal]() race
freezer: remove should_send_signal() and update frozen()
freezer: remove now unused TIF_FREEZE
freezer: make freezing() test freeze conditions in effect instead of TIF_FREEZE
cgroup_freezer: prepare for removal of TIF_FREEZE
freezer: clean up freeze_processes() failure path
freezer: kill PF_FREEZING
freezer: test freezable conditions while holding freezer_lock
freezer: make freezing indicate freeze condition in effect
freezer: use dedicated lock instead of task_lock() + memory barrier
freezer: don't distinguish nosig tasks on thaw
freezer: remove racy clear_freeze_flag() and set PF_NOFREEZE on dead tasks
freezer: rename thaw_process() to __thaw_task() and simplify the implementation
...
try_to_freeze_tasks() that sets TIF_FREEZE for all of the freezable tasks and
either wakes them up, if they are kernel threads, or sends fake signals to them,
if they are user space processes. A task that has TIF_FREEZE set, should react
-to it by calling the function called refrigerator() (defined in
+to it by calling the function called __refrigerator() (defined in
kernel/freezer.c), which sets the task's PF_FROZEN flag, changes its state
to TASK_UNINTERRUPTIBLE and makes it loop until PF_FROZEN is cleared for it.
Then, we say that the task is 'frozen' and therefore the set of functions
defined in kernel/power/process.c, kernel/freezer.c & include/linux/freezer.h).
User space processes are generally frozen before kernel threads.
-It is not recommended to call refrigerator() directly. Instead, it is
-recommended to use the try_to_freeze() function (defined in
-include/linux/freezer.h), that checks the task's TIF_FREEZE flag and makes the
-task enter refrigerator() if the flag is set.
+__refrigerator() must not be called directly. Instead, use the
+try_to_freeze() function (defined in include/linux/freezer.h), that checks
+the task's TIF_FREEZE flag and makes the task enter __refrigerator() if the
+flag is set.
For user space processes try_to_freeze() is called automatically from the
signal-handling code, but the freezable kernel threads need to call it
After the system memory state has been restored from a hibernation image and
devices have been reinitialized, the function thaw_processes() is called in
order to clear the PF_FROZEN flag for each frozen task. Then, the tasks that
-have been frozen leave refrigerator() and continue running.
+have been frozen leave __refrigerator() and continue running.
III. Which kernel threads are freezable?
Kernel threads are not freezable by default. However, a kernel thread may clear
PF_NOFREEZE for itself by calling set_freezable() (the resetting of PF_NOFREEZE
-directly is strongly discouraged). From this point it is regarded as freezable
+directly is not allowed). From this point it is regarded as freezable
and must call try_to_freeze() in a suitable place.
IV. Why do we do that?
#define TIF_UAC_SIGBUS 12 /* ! userspace part of 'osf_sysinfo' */
#define TIF_MEMDIE 13 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 14 /* restore signal mask in do_signal */
-#define TIF_FREEZE 16 /* is freezing for suspend */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
/* Work to do on interrupt/exception return. */
#define _TIF_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
#define TIF_POLLING_NRFLAG 16
#define TIF_USING_IWMMXT 17
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
-#define TIF_FREEZE 19
#define TIF_RESTORE_SIGMASK 20
#define TIF_SECCOMP 21
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
#define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT)
-#define _TIF_FREEZE (1 << TIF_FREEZE)
#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define TIF_RESTORE_SIGMASK 7 /* restore signal mask in do_signal */
#define TIF_CPU_GOING_TO_SLEEP 8 /* CPU is entering sleep 0 mode */
#define TIF_NOTIFY_RESUME 9 /* callback before returning to user */
-#define TIF_FREEZE 29
#define TIF_DEBUG 30 /* debugging enabled */
#define TIF_USERSPACE 31 /* true if FS sets userspace */
#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
#define _TIF_CPU_GOING_TO_SLEEP (1 << TIF_CPU_GOING_TO_SLEEP)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
-#define _TIF_FREEZE (1 << TIF_FREEZE)
/* Note: The masks below must never span more than 16 bits! */
TIF_NEED_RESCHED */
#define TIF_MEMDIE 4 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 5 /* restore signal mask in do_signal() */
-#define TIF_FREEZE 6 /* is freezing for suspend */
#define TIF_IRQ_SYNC 7 /* sync pipeline stage */
#define TIF_NOTIFY_RESUME 8 /* callback before returning to user */
#define TIF_SINGLESTEP 9
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_IRQ_SYNC (1<<TIF_IRQ_SYNC)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
#define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal() */
#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
-#define TIF_FREEZE 18 /* is freezing for suspend */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
#define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
#define TIF_RESTORE_SIGMASK 5 /* restore signal mask in do_signal() */
#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
-#define TIF_FREEZE 18 /* freezing for suspend */
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE (1 << TIF_FREEZE)
#define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
#define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
#define TIF_MEMDIE 4 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 5 /* restore signal mask in do_signal() */
#define TIF_NOTIFY_RESUME 6 /* callback before returning to user */
-#define TIF_FREEZE 16 /* is freezing for suspend */
/* as above, but as bit values */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
#define TIF_MCA_INIT 18 /* this task is processing MCA or INIT */
#define TIF_DB_DISABLED 19 /* debug trap disabled for fsyscall */
-#define TIF_FREEZE 20 /* is freezing for suspend */
#define TIF_RESTORE_RSE 21 /* user RBS is newer than kernel RBS */
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
#define _TIF_MCA_INIT (1 << TIF_MCA_INIT)
#define _TIF_DB_DISABLED (1 << TIF_DB_DISABLED)
-#define _TIF_FREEZE (1 << TIF_FREEZE)
#define _TIF_RESTORE_RSE (1 << TIF_RESTORE_RSE)
/* "work to do on user-return" bits */
#define TIF_USEDFPU 16 /* FPU was used by this task this quantum (SMP) */
#define TIF_POLLING_NRFLAG 17 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
-#define TIF_FREEZE 19 /* is freezing for suspend */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
#define _TIF_USEDFPU (1<<TIF_USEDFPU)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
#define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
#define TIF_DELAYED_TRACE 14 /* single step a syscall */
#define TIF_SYSCALL_TRACE 15 /* syscall trace active */
#define TIF_MEMDIE 16 /* is terminating due to OOM killer */
-#define TIF_FREEZE 17 /* thread is freezing for suspend */
#define TIF_RESTORE_SIGMASK 18 /* restore signal mask in do_signal */
#endif /* _ASM_M68K_THREAD_INFO_H */
#define TIF_MEMDIE 6 /* is terminating due to OOM killer */
#define TIF_SYSCALL_AUDIT 9 /* syscall auditing active */
#define TIF_SECCOMP 10 /* secure computing */
-#define TIF_FREEZE 14 /* Freezing for suspend */
/* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_POLLING_NRFLAG 16
#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
#define _TIF_IRET (1 << TIF_IRET)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE (1 << TIF_FREEZE)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define TIF_USEDFPU 16 /* FPU was used by this task this quantum (SMP) */
#define TIF_POLLING_NRFLAG 17 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
-#define TIF_FREEZE 19
#define TIF_FIXADE 20 /* Fix address errors in software */
#define TIF_LOGADE 21 /* Log address errors to syslog */
#define TIF_32BIT_REGS 22 /* also implies 16/32 fprs */
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
#define _TIF_USEDFPU (1<<TIF_USEDFPU)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_FIXADE (1<<TIF_FIXADE)
#define _TIF_LOGADE (1<<TIF_LOGADE)
#define _TIF_32BIT_REGS (1<<TIF_32BIT_REGS)
#define TIF_RESTORE_SIGMASK 5 /* restore signal mask in do_signal() */
#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
-#define TIF_FREEZE 18 /* freezing for suspend */
#define _TIF_SYSCALL_TRACE +(1 << TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME +(1 << TIF_NOTIFY_RESUME)
#define _TIF_SINGLESTEP +(1 << TIF_SINGLESTEP)
#define _TIF_RESTORE_SIGMASK +(1 << TIF_RESTORE_SIGMASK)
#define _TIF_POLLING_NRFLAG +(1 << TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE +(1 << TIF_FREEZE)
#define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
#define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
#define TIF_32BIT 4 /* 32 bit binary */
#define TIF_MEMDIE 5 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 6 /* restore saved signal mask */
-#define TIF_FREEZE 7 /* is freezing for suspend */
#define TIF_NOTIFY_RESUME 8 /* callback before returning to user */
#define TIF_SINGLESTEP 9 /* single stepping? */
#define TIF_BLOCKSTEP 10 /* branch stepping? */
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
#define _TIF_32BIT (1 << TIF_32BIT)
#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
-#define _TIF_FREEZE (1 << TIF_FREEZE)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
#define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP)
#define TIF_RESTOREALL 11 /* Restore all regs (implies NOERROR) */
#define TIF_NOERROR 12 /* Force successful syscall return */
#define TIF_NOTIFY_RESUME 13 /* callback before returning to user */
-#define TIF_FREEZE 14 /* Freezing for suspend */
#define TIF_SYSCALL_TRACEPOINT 15 /* syscall tracepoint instrumentation */
#define TIF_RUNLATCH 16 /* Is the runlatch enabled? */
#define _TIF_RESTOREALL (1<<TIF_RESTOREALL)
#define _TIF_NOERROR (1<<TIF_NOERROR)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
#define _TIF_RUNLATCH (1<<TIF_RUNLATCH)
#define _TIF_SYSCALL_T_OR_A (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 19 /* restore signal mask in do_signal() */
#define TIF_SINGLE_STEP 20 /* This task is single stepped */
-#define TIF_FREEZE 21 /* thread is freezing for suspend */
#define _TIF_SYSCALL (1<<TIF_SYSCALL)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_31BIT (1<<TIF_31BIT)
#define _TIF_SINGLE_STEP (1<<TIF_SINGLE_STEP)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
#ifdef CONFIG_64BIT
#define is_32bit_task() (test_thread_flag(TIF_31BIT))
#define TIF_SYSCALL_TRACEPOINT 8 /* for ftrace syscall instrumentation */
#define TIF_POLLING_NRFLAG 17 /* true if poll_idle() is polling TIF_NEED_RESCHED */
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
-#define TIF_FREEZE 19 /* Freezing for suspend */
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE (1 << TIF_FREEZE)
/*
* _TIF_ALLWORK_MASK and _TIF_WORK_MASK need to fit within 2 bytes, or we
#define TIF_POLLING_NRFLAG 9 /* true if poll_idle() is polling
* TIF_NEED_RESCHED */
#define TIF_MEMDIE 10 /* is terminating due to OOM killer */
-#define TIF_FREEZE 11 /* is freezing for suspend */
/* as above, but as bit values */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_DO_NOTIFY_RESUME_MASK (_TIF_NOTIFY_RESUME | \
_TIF_SIGPENDING | \
_TIF_RESTORE_SIGMASK)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
#endif /* __KERNEL__ */
/* flag bit 12 is available */
#define TIF_MEMDIE 13 /* is terminating due to OOM killer */
#define TIF_POLLING_NRFLAG 14
-#define TIF_FREEZE 15 /* is freezing for suspend */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_USER_WORK_MASK ((0xff << TI_FLAG_WSAVED_SHIFT) | \
_TIF_DO_NOTIFY_RESUME_MASK | \
#define TIF_MEMDIE 5 /* is terminating due to OOM killer */
#define TIF_SYSCALL_AUDIT 6
#define TIF_RESTORE_SIGMASK 7
-#define TIF_FREEZE 16 /* is freezing for suspend */
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_MEMDIE (1 << TIF_MEMDIE)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
-#define _TIF_FREEZE (1 << TIF_FREEZE)
#endif
#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
#define TIF_SYSCALL_TRACE 8
#define TIF_MEMDIE 18
-#define TIF_FREEZE 19
#define TIF_RESTORE_SIGMASK 20
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
-#define _TIF_FREEZE (1 << TIF_FREEZE)
#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
/*
#define TIF_MEMDIE 20 /* is terminating due to OOM killer */
#define TIF_DEBUG 21 /* uses debug registers */
#define TIF_IO_BITMAP 22 /* uses I/O bitmap */
-#define TIF_FREEZE 23 /* is freezing for suspend */
#define TIF_FORCED_TF 24 /* true if TF in eflags artificially */
#define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */
#define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */
#define _TIF_FORK (1 << TIF_FORK)
#define _TIF_DEBUG (1 << TIF_DEBUG)
#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
-#define _TIF_FREEZE (1 << TIF_FREEZE)
#define _TIF_FORCED_TF (1 << TIF_FORCED_TF)
#define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP)
#define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES)
#define TIF_MEMDIE 5 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 6 /* restore signal mask in do_signal() */
#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */
-#define TIF_FREEZE 17 /* is freezing for suspend */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_IRET (1<<TIF_IRET)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
-#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_WORK_MASK 0x0000FFFE /* work to do on interrupt/exception return */
#define _TIF_ALLWORK_MASK 0x0000FFFF /* work to do on any return to u-space */
init_waitqueue_entry(&wait, current);
- current->flags |= PF_NOFREEZE;
-
for (;;) {
add_wait_queue(&thread->wait_q, &wait);
return error_count;
}
-static void dmatest_callback(void *completion)
+/* poor man's completion - we want to use wait_event_freezable() on it */
+struct dmatest_done {
+ bool done;
+ wait_queue_head_t *wait;
+};
+
+static void dmatest_callback(void *arg)
{
- complete(completion);
+ struct dmatest_done *done = arg;
+
+ done->done = true;
+ wake_up_all(done->wait);
}
/*
*/
static int dmatest_func(void *data)
{
+ DECLARE_WAIT_QUEUE_HEAD_ONSTACK(done_wait);
struct dmatest_thread *thread = data;
+ struct dmatest_done done = { .wait = &done_wait };
struct dma_chan *chan;
const char *thread_name;
unsigned int src_off, dst_off, len;
int i;
thread_name = current->comm;
- set_freezable_with_signal();
+ set_freezable();
ret = -ENOMEM;
struct dma_async_tx_descriptor *tx = NULL;
dma_addr_t dma_srcs[src_cnt];
dma_addr_t dma_dsts[dst_cnt];
- struct completion cmp;
- unsigned long start, tmo, end = 0 /* compiler... */;
- bool reload = true;
u8 align = 0;
total_tests++;
continue;
}
- init_completion(&cmp);
+ done.done = false;
tx->callback = dmatest_callback;
- tx->callback_param = &cmp;
+ tx->callback_param = &done;
cookie = tx->tx_submit(tx);
if (dma_submit_error(cookie)) {
}
dma_async_issue_pending(chan);
- do {
- start = jiffies;
- if (reload)
- end = start + msecs_to_jiffies(timeout);
- else if (end <= start)
- end = start + 1;
- tmo = wait_for_completion_interruptible_timeout(&cmp,
- end - start);
- reload = try_to_freeze();
- } while (tmo == -ERESTARTSYS);
+ wait_event_freezable_timeout(done_wait, done.done,
+ msecs_to_jiffies(timeout));
status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
- if (tmo == 0) {
+ if (!done.done) {
+ /*
+ * We're leaving the timed out dma operation with
+ * dangling pointer to done_wait. To make this
+ * correct, we'll need to allocate wait_done for
+ * each test iteration and perform "who's gonna
+ * free it this time?" dancing. For now, just
+ * leave it dangling.
+ */
pr_warning("%s: #%u: test timed out\n",
thread_name, total_tests - 1);
failed_tests++;
static const unsigned max_i2c_errors = 100;
int ret;
- current->flags |= PF_NOFREEZE;
-
while (!kthread_should_stop()) {
int i;
union {
write_reg(stir, REG_CTRL1, CTRL1_TXPWD|CTRL1_RXPWD);
- refrigerator();
+ try_to_freeze();
if (change_speed(stir, stir->speed))
break;
u32 poll_mask, event_mask;
unsigned int si, so;
unsigned long t;
- unsigned int change_detector, must_reset;
+ unsigned int change_detector;
unsigned int poll_freq;
+ bool was_frozen;
mutex_lock(&hotkey_thread_mutex);
t = 100; /* should never happen... */
}
t = msleep_interruptible(t);
- if (unlikely(kthread_should_stop()))
+ if (unlikely(kthread_freezable_should_stop(&was_frozen)))
break;
- must_reset = try_to_freeze();
- if (t > 0 && !must_reset)
+
+ if (t > 0 && !was_frozen)
continue;
mutex_lock(&hotkey_thread_data_mutex);
- if (must_reset || hotkey_config_change != change_detector) {
+ if (was_frozen || hotkey_config_change != change_detector) {
/* forget old state on thaw or config change */
si = so;
t = 0;
static void hotkey_poll_stop_sync(void)
{
if (tpacpi_hotkey_task) {
- if (frozen(tpacpi_hotkey_task) ||
- freezing(tpacpi_hotkey_task))
- thaw_process(tpacpi_hotkey_task);
-
kthread_stop(tpacpi_hotkey_task);
tpacpi_hotkey_task = NULL;
mutex_lock(&hotkey_thread_mutex);
struct rtsx_chip *chip = dev->chip;
struct Scsi_Host *host = rtsx_to_host(dev);
- current->flags |= PF_NOFREEZE;
-
for (;;) {
if (wait_for_completion_interruptible(&dev->cmnd_ready))
break;
dev_dbg(dev, "device found\n");
- set_freezable_with_signal();
+ set_freezable();
+
/*
* Wait for the timeout to expire or for a disconnect
*
* fail to freeze, but we can't be non-freezable either. Nor can
* khubd freeze while waiting for scanning to complete as it may
* hold the device lock, causing a hang when suspending devices.
- * So we request a fake signal when freezing and use
- * interruptible sleep to kick us out of our wait early when
- * freezing happens.
+ * So instead of using wait_event_freezable(), explicitly test
+ * for (DONT_SCAN || freezing) in interruptible wait and proceed
+ * if any of DONT_SCAN, freezing or timeout has happened.
*/
if (delay_use > 0) {
dev_dbg(dev, "waiting for device to settle "
"before scanning\n");
wait_event_interruptible_timeout(us->delay_wait,
- test_bit(US_FLIDX_DONT_SCAN, &us->dflags),
- delay_use * HZ);
+ test_bit(US_FLIDX_DONT_SCAN, &us->dflags) ||
+ freezing(current), delay_use * HZ);
}
/* If the device is still connected, perform the scanning */
if (freezing(current)) {
worker->working = 0;
spin_unlock_irq(&worker->lock);
- refrigerator();
+ try_to_freeze();
} else {
spin_unlock_irq(&worker->lock);
if (!kthread_should_stop()) {
btrfs_run_defrag_inodes(root->fs_info);
}
- if (freezing(current)) {
- refrigerator();
- } else {
+ if (!try_to_freeze()) {
set_current_state(TASK_INTERRUPTIBLE);
if (!kthread_should_stop())
schedule();
wake_up_process(root->fs_info->cleaner_kthread);
mutex_unlock(&root->fs_info->transaction_kthread_mutex);
- if (freezing(current)) {
- refrigerator();
- } else {
+ if (!try_to_freeze()) {
set_current_state(TASK_INTERRUPTIBLE);
if (!kthread_should_stop() &&
!btrfs_transaction_blocked(root->fs_info))
}
mutex_unlock(&eli->li_list_mtx);
- if (freezing(current))
- refrigerator();
+ try_to_freeze();
cur = jiffies;
if ((time_after_eq(cur, next_wakeup)) ||
trace_writeback_thread_start(bdi);
- while (!kthread_should_stop()) {
+ while (!kthread_freezable_should_stop(NULL)) {
/*
* Remove own delayed wake-up timer, since we are already awake
* and we'll take care of the preriodic write-back.
*/
schedule();
}
-
- try_to_freeze();
}
/* Flush any work that raced with us exiting */
wake_up(&sdp->sd_log_waitq);
t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
- if (freezing(current))
- refrigerator();
+
+ try_to_freeze();
do {
prepare_to_wait(&sdp->sd_logd_waitq, &wait,
/* Check for & recover partially truncated inodes */
quotad_check_trunc_list(sdp);
- if (freezing(current))
- refrigerator();
+ try_to_freeze();
+
t = min(quotad_timeo, statfs_timeo);
prepare_to_wait(&sdp->sd_quota_wait, &wait, TASK_INTERRUPTIBLE);
*/
jbd_debug(1, "Now suspending kjournald\n");
spin_unlock(&journal->j_state_lock);
- refrigerator();
+ try_to_freeze();
spin_lock(&journal->j_state_lock);
} else {
/*
*/
jbd_debug(1, "Now suspending kjournald2\n");
write_unlock(&journal->j_state_lock);
- refrigerator();
+ try_to_freeze();
write_lock(&journal->j_state_lock);
} else {
/*
if (freezing(current)) {
spin_unlock_irq(&log_redrive_lock);
- refrigerator();
+ try_to_freeze();
} else {
set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irq(&log_redrive_lock);
if (freezing(current)) {
LAZY_UNLOCK(flags);
- refrigerator();
+ try_to_freeze();
} else {
DECLARE_WAITQUEUE(wq, current);
if (freezing(current)) {
TXN_UNLOCK();
- refrigerator();
+ try_to_freeze();
} else {
set_current_state(TASK_INTERRUPTIBLE);
TXN_UNLOCK();
if (freezing(current)) {
spin_unlock(&sci->sc_state_lock);
- refrigerator();
+ try_to_freeze();
spin_lock(&sci->sc_state_lock);
} else {
DEFINE_WAIT(wait);
if (unlikely(freezing(current))) {
set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
- refrigerator();
+ try_to_freeze();
} else {
clear_bit(XBT_FORCE_SLEEP, &target->bt_flags);
}
#include <linux/sched.h>
#include <linux/wait.h>
+#include <linux/atomic.h>
#ifdef CONFIG_FREEZER
+extern atomic_t system_freezing_cnt; /* nr of freezing conds in effect */
+extern bool pm_freezing; /* PM freezing in effect */
+extern bool pm_nosig_freezing; /* PM nosig freezing in effect */
+
/*
* Check if a process has been frozen
*/
-static inline int frozen(struct task_struct *p)
+static inline bool frozen(struct task_struct *p)
{
return p->flags & PF_FROZEN;
}
-/*
- * Check if there is a request to freeze a process
- */
-static inline int freezing(struct task_struct *p)
-{
- return test_tsk_thread_flag(p, TIF_FREEZE);
-}
-
-/*
- * Request that a process be frozen
- */
-static inline void set_freeze_flag(struct task_struct *p)
-{
- set_tsk_thread_flag(p, TIF_FREEZE);
-}
+extern bool freezing_slow_path(struct task_struct *p);
/*
- * Sometimes we may need to cancel the previous 'freeze' request
+ * Check if there is a request to freeze a process
*/
-static inline void clear_freeze_flag(struct task_struct *p)
-{
- clear_tsk_thread_flag(p, TIF_FREEZE);
-}
-
-static inline bool should_send_signal(struct task_struct *p)
+static inline bool freezing(struct task_struct *p)
{
- return !(p->flags & PF_FREEZER_NOSIG);
+ if (likely(!atomic_read(&system_freezing_cnt)))
+ return false;
+ return freezing_slow_path(p);
}
/* Takes and releases task alloc lock using task_lock() */
-extern int thaw_process(struct task_struct *p);
+extern void __thaw_task(struct task_struct *t);
-extern void refrigerator(void);
+extern bool __refrigerator(bool check_kthr_stop);
extern int freeze_processes(void);
extern int freeze_kernel_threads(void);
extern void thaw_processes(void);
-static inline int try_to_freeze(void)
+static inline bool try_to_freeze(void)
{
- if (freezing(current)) {
- refrigerator();
- return 1;
- } else
- return 0;
+ might_sleep();
+ if (likely(!freezing(current)))
+ return false;
+ return __refrigerator(false);
}
-extern bool freeze_task(struct task_struct *p, bool sig_only);
-extern void cancel_freezing(struct task_struct *p);
+extern bool freeze_task(struct task_struct *p);
+extern bool set_freezable(void);
#ifdef CONFIG_CGROUP_FREEZER
-extern int cgroup_freezing_or_frozen(struct task_struct *task);
+extern bool cgroup_freezing(struct task_struct *task);
#else /* !CONFIG_CGROUP_FREEZER */
-static inline int cgroup_freezing_or_frozen(struct task_struct *task)
+static inline bool cgroup_freezing(struct task_struct *task)
{
- return 0;
+ return false;
}
#endif /* !CONFIG_CGROUP_FREEZER */
return !!(p->flags & PF_FREEZER_SKIP);
}
-/*
- * Tell the freezer that the current task should be frozen by it
- */
-static inline void set_freezable(void)
-{
- current->flags &= ~PF_NOFREEZE;
-}
-
-/*
- * Tell the freezer that the current task should be frozen by it and that it
- * should send a fake signal to the task to freeze it.
- */
-static inline void set_freezable_with_signal(void)
-{
- current->flags &= ~(PF_NOFREEZE | PF_FREEZER_NOSIG);
-}
-
/*
* Freezer-friendly wrappers around wait_event_interruptible(),
* wait_event_killable() and wait_event_interruptible_timeout(), originally
#define wait_event_freezable(wq, condition) \
({ \
int __retval; \
- do { \
+ for (;;) { \
__retval = wait_event_interruptible(wq, \
(condition) || freezing(current)); \
- if (__retval && !freezing(current)) \
+ if (__retval || (condition)) \
break; \
- else if (!(condition)) \
- __retval = -ERESTARTSYS; \
- } while (try_to_freeze()); \
+ try_to_freeze(); \
+ } \
__retval; \
})
-
#define wait_event_freezable_timeout(wq, condition, timeout) \
({ \
long __retval = timeout; \
- do { \
+ for (;;) { \
__retval = wait_event_interruptible_timeout(wq, \
(condition) || freezing(current), \
__retval); \
- } while (try_to_freeze()); \
+ if (__retval <= 0 || (condition)) \
+ break; \
+ try_to_freeze(); \
+ } \
__retval; \
})
+
#else /* !CONFIG_FREEZER */
-static inline int frozen(struct task_struct *p) { return 0; }
-static inline int freezing(struct task_struct *p) { return 0; }
-static inline void set_freeze_flag(struct task_struct *p) {}
-static inline void clear_freeze_flag(struct task_struct *p) {}
-static inline int thaw_process(struct task_struct *p) { return 1; }
+static inline bool frozen(struct task_struct *p) { return false; }
+static inline bool freezing(struct task_struct *p) { return false; }
-static inline void refrigerator(void) {}
+static inline bool __refrigerator(bool check_kthr_stop) { return false; }
static inline int freeze_processes(void) { return -ENOSYS; }
static inline int freeze_kernel_threads(void) { return -ENOSYS; }
static inline void thaw_processes(void) {}
-static inline int try_to_freeze(void) { return 0; }
+static inline bool try_to_freeze(void) { return false; }
static inline void freezer_do_not_count(void) {}
static inline void freezer_count(void) {}
static inline int freezer_should_skip(struct task_struct *p) { return 0; }
static inline void set_freezable(void) {}
-static inline void set_freezable_with_signal(void) {}
#define wait_event_freezable(wq, condition) \
wait_event_interruptible(wq, condition)
void kthread_bind(struct task_struct *k, unsigned int cpu);
int kthread_stop(struct task_struct *k);
int kthread_should_stop(void);
+bool kthread_freezable_should_stop(bool *was_frozen);
void *kthread_data(struct task_struct *k);
int kthreadd(void *unused);
((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
#define task_contributes_to_load(task) \
((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
- (task->flags & PF_FREEZING) == 0)
+ (task->flags & PF_FROZEN) == 0)
#define __set_task_state(tsk, state_value) \
do { (tsk)->state = (state_value); } while (0)
#define PF_MEMALLOC 0x00000800 /* Allocating memory */
#define PF_NPROC_EXCEEDED 0x00001000 /* set_user noticed that RLIMIT_NPROC was exceeded */
#define PF_USED_MATH 0x00002000 /* if unset the fpu must be initialized before use */
-#define PF_FREEZING 0x00004000 /* freeze in progress. do not account to load */
#define PF_NOFREEZE 0x00008000 /* this thread should not be frozen */
#define PF_FROZEN 0x00010000 /* frozen for system suspend */
#define PF_FSTRANS 0x00020000 /* inside a filesystem transaction */
#define PF_MEMPOLICY 0x10000000 /* Non-default NUMA mempolicy */
#define PF_MUTEX_TESTER 0x20000000 /* Thread belongs to the rt mutex tester */
#define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */
-#define PF_FREEZER_NOSIG 0x80000000 /* Freezer won't send signals to it */
/*
* Only the _current_ task can read/write to tsk->flags, but other
struct freezer, css);
}
-static inline int __cgroup_freezing_or_frozen(struct task_struct *task)
+bool cgroup_freezing(struct task_struct *task)
{
- enum freezer_state state = task_freezer(task)->state;
- return (state == CGROUP_FREEZING) || (state == CGROUP_FROZEN);
-}
+ enum freezer_state state;
+ bool ret;
-int cgroup_freezing_or_frozen(struct task_struct *task)
-{
- int result;
- task_lock(task);
- result = __cgroup_freezing_or_frozen(task);
- task_unlock(task);
- return result;
+ rcu_read_lock();
+ state = task_freezer(task)->state;
+ ret = state == CGROUP_FREEZING || state == CGROUP_FROZEN;
+ rcu_read_unlock();
+
+ return ret;
}
/*
* freezer_can_attach():
* cgroup_mutex (held by caller of can_attach)
*
- * cgroup_freezing_or_frozen():
- * task->alloc_lock (to get task's cgroup)
- *
* freezer_fork() (preserving fork() performance means can't take cgroup_mutex):
* freezer->lock
* sighand->siglock (if the cgroup is freezing)
* write_lock css_set_lock (cgroup iterator start)
* task->alloc_lock
* read_lock css_set_lock (cgroup iterator start)
- * task->alloc_lock (inside thaw_process(), prevents race with refrigerator())
+ * task->alloc_lock (inside __thaw_task(), prevents race with refrigerator())
* sighand->siglock
*/
static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss,
static void freezer_destroy(struct cgroup_subsys *ss,
struct cgroup *cgroup)
{
- kfree(cgroup_freezer(cgroup));
+ struct freezer *freezer = cgroup_freezer(cgroup);
+
+ if (freezer->state != CGROUP_THAWED)
+ atomic_dec(&system_freezing_cnt);
+ kfree(freezer);
}
/*
static int freezer_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
{
- rcu_read_lock();
- if (__cgroup_freezing_or_frozen(tsk)) {
- rcu_read_unlock();
- return -EBUSY;
- }
- rcu_read_unlock();
- return 0;
+ return cgroup_freezing(tsk) ? -EBUSY : 0;
}
static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
/* Locking avoids race with FREEZING -> THAWED transitions. */
if (freezer->state == CGROUP_FREEZING)
- freeze_task(task, true);
+ freeze_task(task);
spin_unlock_irq(&freezer->lock);
}
cgroup_iter_start(cgroup, &it);
while ((task = cgroup_iter_next(cgroup, &it))) {
ntotal++;
- if (frozen(task))
+ if (freezing(task) && frozen(task))
nfrozen++;
}
struct task_struct *task;
unsigned int num_cant_freeze_now = 0;
- freezer->state = CGROUP_FREEZING;
cgroup_iter_start(cgroup, &it);
while ((task = cgroup_iter_next(cgroup, &it))) {
- if (!freeze_task(task, true))
+ if (!freeze_task(task))
continue;
if (frozen(task))
continue;
struct task_struct *task;
cgroup_iter_start(cgroup, &it);
- while ((task = cgroup_iter_next(cgroup, &it))) {
- thaw_process(task);
- }
+ while ((task = cgroup_iter_next(cgroup, &it)))
+ __thaw_task(task);
cgroup_iter_end(cgroup, &it);
-
- freezer->state = CGROUP_THAWED;
}
static int freezer_change_state(struct cgroup *cgroup,
spin_lock_irq(&freezer->lock);
update_if_frozen(cgroup, freezer);
- if (goal_state == freezer->state)
- goto out;
switch (goal_state) {
case CGROUP_THAWED:
+ if (freezer->state != CGROUP_THAWED)
+ atomic_dec(&system_freezing_cnt);
+ freezer->state = CGROUP_THAWED;
unfreeze_cgroup(cgroup, freezer);
break;
case CGROUP_FROZEN:
+ if (freezer->state == CGROUP_THAWED)
+ atomic_inc(&system_freezing_cnt);
+ freezer->state = CGROUP_FREEZING;
retval = try_to_freeze_cgroup(cgroup, freezer);
break;
default:
BUG();
}
-out:
+
spin_unlock_irq(&freezer->lock);
return retval;
tsk->mm = NULL;
up_read(&mm->mmap_sem);
enter_lazy_tlb(mm, current);
- /* We don't want this task to be frozen prematurely */
- clear_freeze_flag(tsk);
task_unlock(tsk);
mm_update_next_owner(mm);
mmput(mm);
exit_rcu();
/* causes final put_task_struct in finish_task_switch(). */
tsk->state = TASK_DEAD;
+ tsk->flags |= PF_NOFREEZE; /* tell freezer to ignore us */
schedule();
BUG();
/* Avoid "noreturn function does return". */
new_flags |= PF_FORKNOEXEC;
new_flags |= PF_STARTING;
p->flags = new_flags;
- clear_freeze_flag(p);
}
SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
#include <linux/export.h>
#include <linux/syscalls.h>
#include <linux/freezer.h>
+#include <linux/kthread.h>
-/*
- * freezing is complete, mark current process as frozen
+/* total number of freezing conditions in effect */
+atomic_t system_freezing_cnt = ATOMIC_INIT(0);
+EXPORT_SYMBOL(system_freezing_cnt);
+
+/* indicate whether PM freezing is in effect, protected by pm_mutex */
+bool pm_freezing;
+bool pm_nosig_freezing;
+
+/* protects freezing and frozen transitions */
+static DEFINE_SPINLOCK(freezer_lock);
+
+/**
+ * freezing_slow_path - slow path for testing whether a task needs to be frozen
+ * @p: task to be tested
+ *
+ * This function is called by freezing() if system_freezing_cnt isn't zero
+ * and tests whether @p needs to enter and stay in frozen state. Can be
+ * called under any context. The freezers are responsible for ensuring the
+ * target tasks see the updated state.
*/
-static inline void frozen_process(void)
+bool freezing_slow_path(struct task_struct *p)
{
- if (!unlikely(current->flags & PF_NOFREEZE)) {
- current->flags |= PF_FROZEN;
- smp_wmb();
- }
- clear_freeze_flag(current);
+ if (p->flags & PF_NOFREEZE)
+ return false;
+
+ if (pm_nosig_freezing || cgroup_freezing(p))
+ return true;
+
+ if (pm_freezing && !(p->flags & PF_KTHREAD))
+ return true;
+
+ return false;
}
+EXPORT_SYMBOL(freezing_slow_path);
/* Refrigerator is place where frozen processes are stored :-). */
-void refrigerator(void)
+bool __refrigerator(bool check_kthr_stop)
{
/* Hmm, should we be allowed to suspend when there are realtime
processes around? */
- long save;
+ bool was_frozen = false;
+ long save = current->state;
- task_lock(current);
- if (freezing(current)) {
- frozen_process();
- task_unlock(current);
- } else {
- task_unlock(current);
- return;
- }
- save = current->state;
pr_debug("%s entered refrigerator\n", current->comm);
- spin_lock_irq(¤t->sighand->siglock);
- recalc_sigpending(); /* We sent fake signal, clean it up */
- spin_unlock_irq(¤t->sighand->siglock);
-
- /* prevent accounting of that task to load */
- current->flags |= PF_FREEZING;
-
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
- if (!frozen(current))
+
+ spin_lock_irq(&freezer_lock);
+ current->flags |= PF_FROZEN;
+ if (!freezing(current) ||
+ (check_kthr_stop && kthread_should_stop()))
+ current->flags &= ~PF_FROZEN;
+ spin_unlock_irq(&freezer_lock);
+
+ if (!(current->flags & PF_FROZEN))
break;
+ was_frozen = true;
schedule();
}
- /* Remove the accounting blocker */
- current->flags &= ~PF_FREEZING;
-
pr_debug("%s left refrigerator\n", current->comm);
- __set_current_state(save);
+
+ /*
+ * Restore saved task state before returning. The mb'd version
+ * needs to be used; otherwise, it might silently break
+ * synchronization which depends on ordered task state change.
+ */
+ set_current_state(save);
+
+ return was_frozen;
}
-EXPORT_SYMBOL(refrigerator);
+EXPORT_SYMBOL(__refrigerator);
static void fake_signal_wake_up(struct task_struct *p)
{
unsigned long flags;
- spin_lock_irqsave(&p->sighand->siglock, flags);
- signal_wake_up(p, 0);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
+ if (lock_task_sighand(p, &flags)) {
+ signal_wake_up(p, 0);
+ unlock_task_sighand(p, &flags);
+ }
}
/**
- * freeze_task - send a freeze request to given task
- * @p: task to send the request to
- * @sig_only: if set, the request will only be sent if the task has the
- * PF_FREEZER_NOSIG flag unset
- * Return value: 'false', if @sig_only is set and the task has
- * PF_FREEZER_NOSIG set or the task is frozen, 'true', otherwise
+ * freeze_task - send a freeze request to given task
+ * @p: task to send the request to
+ *
+ * If @p is freezing, the freeze request is sent by setting %TIF_FREEZE
+ * flag and either sending a fake signal to it or waking it up, depending
+ * on whether it has %PF_FREEZER_NOSIG set.
*
- * The freeze request is sent by setting the tasks's TIF_FREEZE flag and
- * either sending a fake signal to it or waking it up, depending on whether
- * or not it has PF_FREEZER_NOSIG set. If @sig_only is set and the task
- * has PF_FREEZER_NOSIG set (ie. it is a typical kernel thread), its
- * TIF_FREEZE flag will not be set.
+ * RETURNS:
+ * %false, if @p is not freezing or already frozen; %true, otherwise
*/
-bool freeze_task(struct task_struct *p, bool sig_only)
+bool freeze_task(struct task_struct *p)
{
- /*
- * We first check if the task is freezing and next if it has already
- * been frozen to avoid the race with frozen_process() which first marks
- * the task as frozen and next clears its TIF_FREEZE.
- */
- if (!freezing(p)) {
- smp_rmb();
- if (frozen(p))
- return false;
-
- if (!sig_only || should_send_signal(p))
- set_freeze_flag(p);
- else
- return false;
+ unsigned long flags;
+
+ spin_lock_irqsave(&freezer_lock, flags);
+ if (!freezing(p) || frozen(p)) {
+ spin_unlock_irqrestore(&freezer_lock, flags);
+ return false;
}
- if (should_send_signal(p)) {
+ if (!(p->flags & PF_KTHREAD)) {
fake_signal_wake_up(p);
/*
* fake_signal_wake_up() goes through p's scheduler
* TASK_RUNNING transition can't race with task state
* testing in try_to_freeze_tasks().
*/
- } else if (sig_only) {
- return false;
} else {
wake_up_state(p, TASK_INTERRUPTIBLE);
}
+ spin_unlock_irqrestore(&freezer_lock, flags);
return true;
}
-void cancel_freezing(struct task_struct *p)
+void __thaw_task(struct task_struct *p)
{
unsigned long flags;
- if (freezing(p)) {
- pr_debug(" clean up: %s\n", p->comm);
- clear_freeze_flag(p);
- spin_lock_irqsave(&p->sighand->siglock, flags);
- recalc_sigpending_and_wake(p);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
- }
-}
-
-static int __thaw_process(struct task_struct *p)
-{
- if (frozen(p)) {
- p->flags &= ~PF_FROZEN;
- return 1;
- }
- clear_freeze_flag(p);
- return 0;
+ /*
+ * Clear freezing and kick @p if FROZEN. Clearing is guaranteed to
+ * be visible to @p as waking up implies wmb. Waking up inside
+ * freezer_lock also prevents wakeups from leaking outside
+ * refrigerator.
+ */
+ spin_lock_irqsave(&freezer_lock, flags);
+ if (frozen(p))
+ wake_up_process(p);
+ spin_unlock_irqrestore(&freezer_lock, flags);
}
-/*
- * Wake up a frozen process
+/**
+ * set_freezable - make %current freezable
*
- * task_lock() is needed to prevent the race with refrigerator() which may
- * occur if the freezing of tasks fails. Namely, without the lock, if the
- * freezing of tasks failed, thaw_tasks() might have run before a task in
- * refrigerator() could call frozen_process(), in which case the task would be
- * frozen and no one would thaw it.
+ * Mark %current freezable and enter refrigerator if necessary.
*/
-int thaw_process(struct task_struct *p)
+bool set_freezable(void)
{
- task_lock(p);
- if (__thaw_process(p) == 1) {
- task_unlock(p);
- wake_up_process(p);
- return 1;
- }
- task_unlock(p);
- return 0;
+ might_sleep();
+
+ /*
+ * Modify flags while holding freezer_lock. This ensures the
+ * freezer notices that we aren't frozen yet or the freezing
+ * condition is visible to try_to_freeze() below.
+ */
+ spin_lock_irq(&freezer_lock);
+ current->flags &= ~PF_NOFREEZE;
+ spin_unlock_irq(&freezer_lock);
+
+ return try_to_freeze();
}
-EXPORT_SYMBOL(thaw_process);
+EXPORT_SYMBOL(set_freezable);
}
EXPORT_SYMBOL(kthread_should_stop);
+/**
+ * kthread_freezable_should_stop - should this freezable kthread return now?
+ * @was_frozen: optional out parameter, indicates whether %current was frozen
+ *
+ * kthread_should_stop() for freezable kthreads, which will enter
+ * refrigerator if necessary. This function is safe from kthread_stop() /
+ * freezer deadlock and freezable kthreads should use this function instead
+ * of calling try_to_freeze() directly.
+ */
+bool kthread_freezable_should_stop(bool *was_frozen)
+{
+ bool frozen = false;
+
+ might_sleep();
+
+ if (unlikely(freezing(current)))
+ frozen = __refrigerator(true);
+
+ if (was_frozen)
+ *was_frozen = frozen;
+
+ return kthread_should_stop();
+}
+EXPORT_SYMBOL_GPL(kthread_freezable_should_stop);
+
/**
* kthread_data - return data value specified on kthread creation
* @task: kthread task in question
set_cpus_allowed_ptr(tsk, cpu_all_mask);
set_mems_allowed(node_states[N_HIGH_MEMORY]);
- current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG;
+ current->flags |= PF_NOFREEZE;
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
while(1);
}
-static int prepare_processes(void)
-{
- int error = 0;
-
- if (freeze_processes()) {
- error = -EBUSY;
- thaw_processes();
- }
- return error;
-}
-
/**
* hibernate - Carry out system hibernation, including saving the image.
*/
sys_sync();
printk("done.\n");
- error = prepare_processes();
+ error = freeze_processes();
if (error)
goto Finish;
goto close_finish;
pr_debug("PM: Preparing processes for restore.\n");
- error = prepare_processes();
+ error = freeze_processes();
if (error) {
swsusp_close(FMODE_READ);
goto Done;
*/
#define TIMEOUT (20 * HZ)
-static inline int freezable(struct task_struct * p)
-{
- if ((p == current) ||
- (p->flags & PF_NOFREEZE) ||
- (p->exit_state != 0))
- return 0;
- return 1;
-}
-
-static int try_to_freeze_tasks(bool sig_only)
+static int try_to_freeze_tasks(bool user_only)
{
struct task_struct *g, *p;
unsigned long end_time;
end_time = jiffies + TIMEOUT;
- if (!sig_only)
+ if (!user_only)
freeze_workqueues_begin();
while (true) {
todo = 0;
read_lock(&tasklist_lock);
do_each_thread(g, p) {
- if (frozen(p) || !freezable(p))
- continue;
-
- if (!freeze_task(p, sig_only))
+ if (p == current || !freeze_task(p))
continue;
/*
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
- if (!sig_only) {
+ if (!user_only) {
wq_busy = freeze_workqueues_busy();
todo += wq_busy;
}
elapsed_csecs = elapsed_csecs64;
if (todo) {
- /* This does not unfreeze processes that are already frozen
- * (we have slightly ugly calling convention in that respect,
- * and caller must call thaw_processes() if something fails),
- * but it cleans up leftover PF_FREEZE requests.
- */
printk("\n");
printk(KERN_ERR "Freezing of tasks %s after %d.%02d seconds "
"(%d tasks refusing to freeze, wq_busy=%d):\n",
elapsed_csecs / 100, elapsed_csecs % 100,
todo - wq_busy, wq_busy);
- thaw_workqueues();
-
read_lock(&tasklist_lock);
do_each_thread(g, p) {
- task_lock(p);
- if (!wakeup && freezing(p) && !freezer_should_skip(p))
+ if (!wakeup && !freezer_should_skip(p) &&
+ p != current && freezing(p) && !frozen(p))
sched_show_task(p);
- cancel_freezing(p);
- task_unlock(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
} else {
/**
* freeze_processes - Signal user space processes to enter the refrigerator.
+ *
+ * On success, returns 0. On failure, -errno and system is fully thawed.
*/
int freeze_processes(void)
{
int error;
+ if (!pm_freezing)
+ atomic_inc(&system_freezing_cnt);
+
printk("Freezing user space processes ... ");
+ pm_freezing = true;
error = try_to_freeze_tasks(true);
if (!error) {
printk("done.");
printk("\n");
BUG_ON(in_atomic());
+ if (error)
+ thaw_processes();
return error;
}
/**
* freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
+ *
+ * On success, returns 0. On failure, -errno and system is fully thawed.
*/
int freeze_kernel_threads(void)
{
int error;
printk("Freezing remaining freezable tasks ... ");
+ pm_nosig_freezing = true;
error = try_to_freeze_tasks(false);
if (!error)
printk("done.");
printk("\n");
BUG_ON(in_atomic());
+ if (error)
+ thaw_processes();
return error;
}
-static void thaw_tasks(bool nosig_only)
+void thaw_processes(void)
{
struct task_struct *g, *p;
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- if (!freezable(p))
- continue;
+ if (pm_freezing)
+ atomic_dec(&system_freezing_cnt);
+ pm_freezing = false;
+ pm_nosig_freezing = false;
- if (nosig_only && should_send_signal(p))
- continue;
+ oom_killer_enable();
+
+ printk("Restarting tasks ... ");
- if (cgroup_freezing_or_frozen(p))
- continue;
+ thaw_workqueues();
- thaw_process(p);
+ read_lock(&tasklist_lock);
+ do_each_thread(g, p) {
+ __thaw_task(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
-}
-void thaw_processes(void)
-{
- oom_killer_enable();
-
- printk("Restarting tasks ... ");
- thaw_workqueues();
- thaw_tasks(true);
- thaw_tasks(false);
schedule();
printk("done.\n");
}
goto Finish;
error = suspend_freeze_processes();
- if (error) {
- suspend_stats.failed_freeze++;
- dpm_save_failed_step(SUSPEND_FREEZE);
- } else
+ if (!error)
return 0;
- suspend_thaw_processes();
+ suspend_stats.failed_freeze++;
+ dpm_save_failed_step(SUSPEND_FREEZE);
usermodehelper_enable();
Finish:
pm_notifier_call_chain(PM_POST_SUSPEND);
break;
error = freeze_processes();
- if (error) {
- thaw_processes();
+ if (error)
usermodehelper_enable();
- }
if (!error)
data->frozen = 1;
break;
/*
* Finally, kill the kernel thread. We don't need to be RCU
- * safe anymore, since the bdi is gone from visibility. Force
- * unfreeze of the thread before calling kthread_stop(), otherwise
- * it would never exet if it is currently stuck in the refrigerator.
+ * safe anymore, since the bdi is gone from visibility.
*/
- if (bdi->wb.task) {
- thaw_process(bdi->wb.task);
+ if (bdi->wb.task)
kthread_stop(bdi->wb.task);
- }
}
/*
*/
if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
if (unlikely(frozen(p)))
- thaw_process(p);
+ __thaw_task(p);
return ERR_PTR(-1UL);
}
if (!p->mm)
projects / cascardo / linux.git / commitdiff