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Subject[PATCH v2] auxdisplay: Remove in_interrupt() usage.
charlcd_write() is invoked as a VFS->write() callback and as such it is
always invoked from preemptible context and may sleep.

charlcd_puts() is invoked from register/unregister callback which is
preemptible. The reboot notifier callback is also invoked from
preemptible context.

Therefore there is no need to use `in_interrupt()' to figure out if it
is safe to sleep because it always is.
Using `schedule()' to schedule (and be friendly to others) is
discouraged and `cond_resched()' should be used instead.

Remove `in_interrupt()' and use `cond_resched()' to schedule every 32
iteration if needed.

Cc: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---

v1…v2: Spelling fixes.

drivers/auxdisplay/charlcd.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c
index f43430e9dceed..fbfce95919f72 100644
--- a/drivers/auxdisplay/charlcd.c
+++ b/drivers/auxdisplay/charlcd.c
@@ -470,12 +470,8 @@ static ssize_t charlcd_write(struct file *file, const char __user *buf,
char c;

for (; count-- > 0; (*ppos)++, tmp++) {
- if (!in_interrupt() && (((count + 1) & 0x1f) == 0))
- /*
- * let's be a little nice with other processes
- * that need some CPU
- */
- schedule();
+ if (((count + 1) & 0x1f) == 0)
+ cond_resched();

if (get_user(c, tmp))
return -EFAULT;
@@ -537,12 +533,8 @@ static void charlcd_puts(struct charlcd *lcd, const char *s)
int count = strlen(s);

for (; count-- > 0; tmp++) {
- if (!in_interrupt() && (((count + 1) & 0x1f) == 0))
- /*
- * let's be a little nice with other processes
- * that need some CPU
- */
- schedule();
+ if (((count + 1) & 0x1f) == 0)
+ cond_resched();

charlcd_write_char(lcd, *tmp);
}
--
2.30.0
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