mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-28 13:22:57 +00:00
Code Issues Releases Wiki Activity

char: pcmcia: cm4000_cs: Replace mdelay with usleep_range in set_protocol

Browse source 
set_protocol() is never called in atomic context.

The call chains ending up at set_protocol() are:
[1] set_protocol() <- monitor_card()
[2] set_protocol() <- cmm_ioctl()
monitor_card() is only set in setup_timer(), and cmm_ioctl() is only
set as ".unlocked_ioctl" in file_operations structure "cm4000_fops".

Despite never getting called from atomic context, set_protocol() calls
mdelay(10), i.e. busy wait for 10ms.
That is not necessary and can be replaced with usleep_range to
avoid busy waiting.

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Acked-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Jia-Ju Bai 2018-03-18 22:49:57 +08:00 committed by Dominik Brodowski
parent dc245cfa82
commit be826ada52
1 changed files with 2 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
drivers/char/pcmcia/cm4000_cs.c
View file

@ -530,7 +530,7 @@ static int set_protocol(struct cm4000_dev *dev, struct ptsreq *ptsreq)
DEBUGP(5, dev, "NumRecBytes is valid\n");
break;
}
mdelay(10);
usleep_range(10000, 11000);
}
if (i == 100) {
DEBUGP(5, dev, "Timeout waiting for NumRecBytes getting "
@ -546,7 +546,7 @@ static int set_protocol(struct cm4000_dev *dev, struct ptsreq *ptsreq)
DEBUGP(2, dev, "NumRecBytes = %i\n", num_bytes_read);
break;
}
mdelay(10);
usleep_range(10000, 11000);
}
/* check whether it is a short PTS reply? */