[PATCH 4.6 042/203] rtlwifi: Fix scheduling while atomic error from commit 49f86ec21c01

Greg Kroah-Hartman
2016-07-25T22:25:38Z

From: Larry Finger <Larry.Finger@lwfinger.net>

commit de26859dcf363d520cc44e59f6dcaf20ebe0aadf upstream.

Commit 49f86ec21c01 ("rtlwifi: Change long delays to sleeps") was correct
for most cases; however, driver rtl8192ce calls the affected routines while
in atomic context. The kernel bug output is as follows:

BUG: scheduling while atomic: wpa_supplicant/627/0x00000002
[...]
[<ffffffff815c2b39>] __schedule+0x899/0xad0
[<ffffffff815c2dac>] schedule+0x3c/0x90
[<ffffffff815c5bb2>] schedule_hrtimeout_range_clock+0xa2/0x120
[<ffffffff810e8b80>] ? hrtimer_init+0x120/0x120
[<ffffffff815c5ba6>] ? schedule_hrtimeout_range_clock+0x96/0x120
[<ffffffff815c5c43>] schedule_hrtimeout_range+0x13/0x20
[<ffffffff815c568f>] usleep_range+0x4f/0x70
[<ffffffffa0667218>] rtl_rfreg_delay+0x38/0x50 [rtlwifi]
[<ffffffffa06dd0e7>] rtl92c_phy_config_rf_with_headerfile+0xc7/0xe0 [rtl8192ce]

To fix this bug, three of the changes from delay to sleep are reverted.
Unfortunately, one of the changes involves a delay of 50 msec. The calling
code will be modified so that this long delay can be avoided; however,
this change is being pushed now to fix the problem in kernel 4.6.0.

Fixes: 49f86ec21c01 ("rtlwifi: Change long delays to sleeps")
Reported-by: James Feeney <james@nurealm.net>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: James Feeney <james@nurealm.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/wireless/realtek/rtlwifi/core.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/net/wireless/realtek/rtlwifi/core.c
+++ b/drivers/net/wireless/realtek/rtlwifi/core.c
@@ -54,7 +54,7 @@ EXPORT_SYMBOL(channel5g_80m);
void rtl_addr_delay(u32 addr)
{
if (addr == 0xfe)
- msleep(50);
+ mdelay(50);
else if (addr == 0xfd)
msleep(5);
else if (addr == 0xfc)
@@ -75,7 +75,7 @@ void rtl_rfreg_delay(struct ieee80211_hw
rtl_addr_delay(addr);
} else {
rtl_set_rfreg(hw, rfpath, addr, mask, data);
- usleep_range(1, 2);
+ udelay(1);
}
}
EXPORT_SYMBOL(rtl_rfreg_delay);
@@ -86,7 +86,7 @@ void rtl_bb_delay(struct ieee80211_hw *h
rtl_addr_delay(addr);
} else {
rtl_set_bbreg(hw, addr, MASKDWORD, data);
- usleep_range(1, 2);
+ udelay(1);
}
}
EXPORT_SYMBOL(rtl_bb_delay);