2023-01-18 14:38:02

by Duoming Zhou

[permalink] [raw]
Subject: [RESEND PATCH v2] Revert "char: pcmcia: cm4000_cs: Replace mdelay with usleep_range in set_protocol"

This reverts commit be826ada52f1fcabed5b5217c94609ebf5967211.

The function monitor_card() is a timer handler that runs in an
atomic context, but it calls usleep_range() that can sleep.
As a result, the sleep-in-atomic-context bugs will happen.
The process is shown below:

(atomic context)
monitor_card()
set_protocol()
usleep_range() //sleep

The origin commit c1986ee9bea3 ("[PATCH] New Omnikey Cardman
4000 driver") works fine.

Fixes: be826ada52f1 ("char: pcmcia: cm4000_cs: Replace mdelay with usleep_range in set_protocol")
Signed-off-by: Duoming Zhou <[email protected]>
---
Changes in v2:
- Add comments so that this will not be changed again in the future.

drivers/char/pcmcia/cm4000_cs.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/char/pcmcia/cm4000_cs.c b/drivers/char/pcmcia/cm4000_cs.c
index adaec8fd4b1..e656f42a28a 100644
--- a/drivers/char/pcmcia/cm4000_cs.c
+++ b/drivers/char/pcmcia/cm4000_cs.c
@@ -529,7 +529,8 @@ static int set_protocol(struct cm4000_dev *dev, struct ptsreq *ptsreq)
DEBUGP(5, dev, "NumRecBytes is valid\n");
break;
}
- usleep_range(10000, 11000);
+ /* can not sleep as this is in atomic context */
+ mdelay(10);
}
if (i == 100) {
DEBUGP(5, dev, "Timeout waiting for NumRecBytes getting "
@@ -549,7 +550,8 @@ static int set_protocol(struct cm4000_dev *dev, struct ptsreq *ptsreq)
}
break;
}
- usleep_range(10000, 11000);
+ /* can not sleep as this is in atomic context */
+ mdelay(10);
}

/* check whether it is a short PTS reply? */
--
2.17.1