lkml.org 
[lkml]   [2017]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v1 1/1] watchdog: iTCO_wdt: Move update_no_reboot_bit() out of atomic context
Date
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

In iTCO_wdt_start() and iTCO_wdt_stop() functions, update_no_reboot_bit()
call has been made within io_lock spin lock context. But if the
update_no_reboot_bit() function is implemented by chipset/PMC driver
then we can't be sure whether their implementation does not include any
sleeping calls. Also, iTCO_wdt io_lock is mainly intended for protecting the
watchdog IO operations and has nothing to with no_reboot_bit update.

Currently, update_no_reboot_bit() function implemented by intel_pmc_ipc
driver uses mutex_lock() which in turn causes "sleeping into atomic
context" issue in iTCO_wdt_start()/iTCO_wdt_stop() functions.

So moving the update_no_reboot_bit() function out of atomic context.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
drivers/watchdog/iTCO_wdt.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index c4f6587..5a018b2 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -243,17 +243,16 @@ static int iTCO_wdt_start(struct watchdog_device *wd_dev)
struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
unsigned int val;

- spin_lock(&p->io_lock);
-
- iTCO_vendor_pre_start(p->smi_res, wd_dev->timeout);
-
/* disable chipset's NO_REBOOT bit */
if (p->update_no_reboot_bit(p->no_reboot_priv, false)) {
- spin_unlock(&p->io_lock);
pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware/BIOS\n");
return -EIO;
}

+ spin_lock(&p->io_lock);
+
+ iTCO_vendor_pre_start(p->smi_res, wd_dev->timeout);
+
/* Force the timer to its reload value by writing to the TCO_RLD
register */
if (p->iTCO_version >= 2)
@@ -288,11 +287,11 @@ static int iTCO_wdt_stop(struct watchdog_device *wd_dev)
outw(val, TCO1_CNT(p));
val = inw(TCO1_CNT(p));

+ spin_unlock(&p->io_lock);
+
/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
p->update_no_reboot_bit(p->no_reboot_priv, true);

- spin_unlock(&p->io_lock);
-
if ((val & 0x0800) == 0)
return -1;
return 0;
--
2.7.4
\
 
 \ /
  Last update: 2017-07-27 20:09    [W:0.037 / U:0.944 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site