[PATCH 4.19 294/361] Revert "media: dvbsky: use just one mutex for serializing device R/W ops"

Greg Kroah-Hartman
2018-11-11T22:28:36Z

From: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

commit 9afc82194de9a1ce298f0d77d7d779d585bf962c upstream.

As pointed at:
https://bugzilla.kernel.org/show_bug.cgi?id=199323

This patch causes a bad effect on RPi. I suspect that the root
cause is at the USB out of tree RPi driver, with uses high priority
interrupts instead of normal ones. Anyway, as this patch
is mostly a cleanup, better to revert it.

This reverts commit 7d95fb746c4eece67308f1642a666ea1ebdbd2cc.

Cc: stable@vger.kernel.org # For Kernel 4.18
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/media/usb/dvb-usb-v2/dvbsky.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

--- a/drivers/media/usb/dvb-usb-v2/dvbsky.c
+++ b/drivers/media/usb/dvb-usb-v2/dvbsky.c
@@ -31,6 +31,7 @@ MODULE_PARM_DESC(disable_rc, "Disable in
DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);

struct dvbsky_state {
+ struct mutex stream_mutex;
u8 ibuf[DVBSKY_BUF_LEN];
u8 obuf[DVBSKY_BUF_LEN];
u8 last_lock;
@@ -67,17 +68,18 @@ static int dvbsky_usb_generic_rw(struct

static int dvbsky_stream_ctrl(struct dvb_usb_device *d, u8 onoff)
{
+ struct dvbsky_state *state = d_to_priv(d);
int ret;
- static u8 obuf_pre[3] = { 0x37, 0, 0 };
- static u8 obuf_post[3] = { 0x36, 3, 0 };
+ u8 obuf_pre[3] = { 0x37, 0, 0 };
+ u8 obuf_post[3] = { 0x36, 3, 0 };

- mutex_lock(&d->usb_mutex);
- ret = dvb_usbv2_generic_rw_locked(d, obuf_pre, 3, NULL, 0);
+ mutex_lock(&state->stream_mutex);
+ ret = dvbsky_usb_generic_rw(d, obuf_pre, 3, NULL, 0);
if (!ret && onoff) {
msleep(20);
- ret = dvb_usbv2_generic_rw_locked(d, obuf_post, 3, NULL, 0);
+ ret = dvbsky_usb_generic_rw(d, obuf_post, 3, NULL, 0);
}
- mutex_unlock(&d->usb_mutex);
+ mutex_unlock(&state->stream_mutex);
return ret;
}

@@ -606,6 +608,8 @@ static int dvbsky_init(struct dvb_usb_de
if (ret)
return ret;
*/
+ mutex_init(&state->stream_mutex);
+
state->last_lock = 0;

return 0;