[lkml]   [2018]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH] bluetooth: hci_ll: Replace mdelay with msleep in download_firmware
download_firmware() is never called from atomic context.

It is only called by ll_setup() that is called only via function pointer
"->setup" used in hci_uart_setup() in drivers/bluetooth/hci_serdev.c and
drivers/bluetooth/hci_ldisc.c. hci_uart_setup() is called only
via function pointer "->setup" used in hci_dev_do_open()
in net/bluetooth/hci_core.c.
All of the above functions do not enter atomic context.

Besides, ll_setup() calls msleep() and hci_dev_do_open calls mutex_lock().
So it indicates that all the above functions call functions that can sleep.

Despite never getting called from atomic context, download_firmware()
calls mdelay() for busy wait.
That is not necessary and can be replaced with msleep to avoid busy wait.

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

Signed-off-by: Jia-Ju Bai <>
drivers/bluetooth/hci_ll.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/bluetooth/hci_ll.c b/drivers/bluetooth/hci_ll.c
index e2c078d..f804adc 100644
--- a/drivers/bluetooth/hci_ll.c
+++ b/drivers/bluetooth/hci_ll.c
@@ -644,7 +644,7 @@ static int download_firmware(struct ll_device *lldev)
case ACTION_DELAY: /* sleep */
bt_dev_info(lldev->hu.hdev, "sleep command in scr");
- mdelay(((struct bts_action_delay *)action_ptr)->msec);
+ msleep(((struct bts_action_delay *)action_ptr)->msec);
len -= (sizeof(struct bts_action) +
 \ /
  Last update: 2018-01-27 11:00    [W:0.033 / U:0.964 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site