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Subject[PATCH 02/17] freezer: don't unnecessarily set PF_NOFREEZE explicitly
Date
Some drivers set PF_NOFREEZE in their kthread functions which is
completely unnecessary and racy - some part of freezer code doesn't
consider cases where PF_NOFREEZE is set asynchronous to freezer
operations.

In general, there's no reason to allow setting PF_NOFREEZE explicitly.
Remove them and change the documentation to note that setting
PF_NOFREEZE directly isn't allowed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: "Gustavo F. Padovan" <padovan@profusion.mobi>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: wwang <wei_wang@realsil.com.cn>
---
Documentation/power/freezing-of-tasks.txt | 2 +-
drivers/bluetooth/btmrvl_main.c | 2 --
drivers/mfd/twl4030-irq.c | 3 ---
drivers/mfd/twl6030-irq.c | 2 --
drivers/staging/rts_pstor/rtsx.c | 2 --
5 files changed, 1 insertions(+), 10 deletions(-)
diff --git a/Documentation/power/freezing-of-tasks.txt b/Documentation/power/freezing-of-tasks.txt
index 38b5724..710c965 100644
--- a/Documentation/power/freezing-of-tasks.txt
+++ b/Documentation/power/freezing-of-tasks.txt
@@ -67,7 +67,7 @@ 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?
diff --git a/drivers/bluetooth/btmrvl_main.c b/drivers/bluetooth/btmrvl_main.c
index 548d1d9..57312d4 100644
--- a/drivers/bluetooth/btmrvl_main.c
+++ b/drivers/bluetooth/btmrvl_main.c
@@ -473,8 +473,6 @@ static int btmrvl_service_main_thread(void *data)

init_waitqueue_entry(&wait, current);

- current->flags |= PF_NOFREEZE;
-
for (;;) {
add_wait_queue(&thread->wait_q, &wait);

diff --git a/drivers/mfd/twl4030-irq.c b/drivers/mfd/twl4030-irq.c
index 8a7ee31..6aae831 100644
--- a/drivers/mfd/twl4030-irq.c
+++ b/drivers/mfd/twl4030-irq.c
@@ -289,9 +289,6 @@ static int twl4030_irq_thread(void *data)
static unsigned i2c_errors;
static const unsigned max_i2c_errors = 100;

-
- current->flags |= PF_NOFREEZE;
-
while (!kthread_should_stop()) {
int ret;
int module_irq;
diff --git a/drivers/mfd/twl6030-irq.c b/drivers/mfd/twl6030-irq.c
index eb3b5f8..6fd7795 100644
--- a/drivers/mfd/twl6030-irq.c
+++ b/drivers/mfd/twl6030-irq.c
@@ -96,8 +96,6 @@ static int twl6030_irq_thread(void *data)
static const unsigned max_i2c_errors = 100;
int ret;

- current->flags |= PF_NOFREEZE;
-
while (!kthread_should_stop()) {
int i;
union {
diff --git a/drivers/staging/rts_pstor/rtsx.c b/drivers/staging/rts_pstor/rtsx.c
index 480b0ed..8a7803c 100644
--- a/drivers/staging/rts_pstor/rtsx.c
+++ b/drivers/staging/rts_pstor/rtsx.c
@@ -466,8 +466,6 @@ static int rtsx_control_thread(void *__dev)
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;
--
1.7.3.1


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