usb: cdc-acm: fix cooldown mechanism

Commit a4e7279cd1d1 ("cdc-acm: introduce a cool down") is causing
regression if there is some USB error, such as -EPROTO.

This has been reported on some samples of the Odroid-N2 using the Combee II
Zibgee USB dongle.

> struct acm *acm = container_of(work, struct acm, work)

is incorrect in case of a delayed work and causes warnings, usually from
the workqueue:

> WARNING: CPU: 0 PID: 0 at kernel/workqueue.c:1474 __queue_work+0x480/0x528.

When this happens, USB eventually stops working completely after a while.
Also the ACM_ERROR_DELAY bit is never set, so the cooldown mechanism
previously introduced cannot be triggered and acm_submit_read_urb() is
never called.

This changes makes the cdc-acm driver use a single delayed work, fixing the
pointer arithmetic in acm_softint() and set the ACM_ERROR_DELAY when the
cooldown mechanism appear to be needed.

Fixes: a4e7279cd1d1 ("cdc-acm: introduce a cool down")
Cc: Oliver Neukum <[email protected]>
Reported-by: Pascal Vizeli <[email protected]>
Acked-by: Oliver Neukum <[email protected]>
Signed-off-by: Jerome Brunet <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions