Hi Tobias,
> On Apr 22, 2020, at 10:21, Tony Chuang <yhchuang@xxxxxxxxxxx> wrote:
>
> Brian Norris <briannorris@xxxxxxxxxxxx> :
>>
>> I'm not sure about the first half your problem, but for the
>> scheduling-while-atomic:
>>
>> On Tue, Apr 21, 2020 at 2:16 PM Tobias S. Predel
>> <tobias.predel@xxxxxxxxx> wrote:
>>> [28125.482259] BUG: scheduling while atomic:
>> kworker/u16:0/33416/0x00000002
>> ...
>>> [28125.482436] Preemption disabled at:
>>> [28125.482443] [<0000000000000000>] 0x0
>>
>> ^^ This line is a bit weird -- shouldn't this have a real PC?
>>
>>> [28125.482452] CPU: 5 PID: 33416 Comm: kworker/u16:0 Tainted: G
>> W 5.7.0-rc2-next-20200421-1-next-git #1
>>> [28125.482456] Hardware name: HP HP ProBook 430 G5/8377, BIOS Q85
>> Ver. 01.09.01 10/15/2019
>>> [28125.482477] Workqueue: phy0 rtw_watch_dog_work [rtw88]
>>> [28125.482481] Call Trace:
>>> [28125.482495] dump_stack+0x66/0x90
>>> [28125.482505] __schedule_bug.cold+0x8e/0x9b
>>> [28125.482512] __schedule+0x686/0x7b0
>>> [28125.482520] ? _raw_spin_unlock_irqrestore+0x20/0x40
>>> [28125.482525] schedule+0x46/0xf0
>>> [28125.482531] schedule_hrtimeout_range_clock+0xa5/0x120
>>> [28125.482540] ? hrtimer_init_sleeper+0xa0/0xa0
>>> [28125.482546] usleep_range+0x67/0x90
>>> [28125.482568] rtw_fw_send_h2c_command+0xe0/0x1a0 [rtw88]
>>> [28125.482590] rtw_fw_set_pwr_mode+0x95/0xb0 [rtw88]
>>> [28125.482610] rtw_enter_lps+0xa1/0x100 [rtw88]
>>> [28125.482625] rtw_watch_dog_work+0x21c/0x230 [rtw88]
>>> [28125.482635] process_one_work+0x1da/0x3d0
>>> [28125.482643] worker_thread+0x4a/0x3d0
>>> [28125.482651] kthread+0x122/0x160
>>> [28125.482658] ? process_one_work+0x3d0/0x3d0
>>> [28125.482663] ? kthread_park+0x90/0x90
>>> [28125.482670] ret_from_fork+0x1f/0x40
>>
>> This looks like it might be a regression here:
>>
>> commit 6343a6d4b2130be9323f347d60af8a7ba8f7242c
>> Author: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
>> Date: Tue Apr 7 15:33:31 2020 +0800
>>
>> rtw88: Add delay on polling h2c command status bit
>>
>> That poll macros is using usleep, which obviously can sleep. We need
>> to be using a udelay-variant instead.
>>
>
> Maybe we need an atomic version of read_poll_timeout() ?
> I am not sure if this is required, but seems like it is useful for me.
> Noticed much of them have its atomic version, but not for this new added one.
Tony and Brian are right.
Tobias, can you please test the following patch:
diff --git a/drivers/net/wireless/realtek/rtw88/fw.c b/drivers/net/wireless/realtek/rtw88/fw.c
index 245da96dfddc..e44767ec0532 100644
--- a/drivers/net/wireless/realtek/rtw88/fw.c
+++ b/drivers/net/wireless/realtek/rtw88/fw.c
@@ -228,7 +228,7 @@ static void rtw_fw_send_h2c_command(struct rtw_dev *rtwdev,
goto out;
}
- ret = read_poll_timeout(rtw_read8, box_state,
+ ret = read_poll_timeout_atomic(rtw_read8, box_state,
!((box_state >> box) & 0x1), 100, 3000, false,
rtwdev, REG_HMETFR);
diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
index cb20c733b15a..bc89ac625f26 100644
--- a/include/linux/iopoll.h
+++ b/include/linux/iopoll.h
@@ -57,6 +57,48 @@
(cond) ? 0 : -ETIMEDOUT; \
})
+/**
+ * read_poll_timeout_atomic - Periodically poll an address until a condition is
+ * met or a timeout occurs
+ * @op: accessor function (takes @addr as its only argument)
+ * @addr: Address to poll
+ * @val: Variable to read the value into
+ * @cond: Break condition (usually involving @val)
+ * @delay_us: Time to udelay between reads in us (0 tight-loops). Should
+ * be less than ~10us since udelay is used (see
+ * Documentation/timers/timers-howto.rst).
+ * @timeout_us: Timeout in us, 0 means never timeout
+ * @delay_before_read: if it is true, delay @delay_us before read.
+ *
+ * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
+ * case, the last read value at @args is stored in @val.
+ *
+ * When available, you'll probably want to use one of the specialized
+ * macros defined below rather than this macro directly.
+ */
+#define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \
+ delay_before_read, args...) \
+({ \
+ u64 __timeout_us = (timeout_us); \
+ unsigned long __delay_us = (delay_us); \
+ ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
+ if (delay_before_read && __delay_us) \
+ udelay(__delay_us); \
+ for (;;) { \
+ (val) = op(args); \
+ if (cond) \
+ break; \
+ if (__timeout_us && \
+ ktime_compare(ktime_get(), __timeout) > 0) { \
+ (val) = op(args); \
+ break; \
+ } \
+ if (__delay_us) \
+ } \
+ (cond) ? 0 : -ETIMEDOUT; \
+})
+
/**
* readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
* @op: accessor function (takes @addr as its only argument)
@@ -96,25 +138,7 @@
* macros defined below rather than this macro directly.
*/
#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
-({ \
- u64 __timeout_us = (timeout_us); \
- unsigned long __delay_us = (delay_us); \
- ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
- for (;;) { \
- (val) = op(addr); \
- if (cond) \
- break; \
- if (__timeout_us && \
- ktime_compare(ktime_get(), __timeout) > 0) { \
- (val) = op(addr); \
- break; \
- } \
- if (__delay_us) \
- udelay(__delay_us); \
- } \
- (cond) ? 0 : -ETIMEDOUT; \
-})
-
+ read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr)
#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
>
> Yen-Hsuan
