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

[Mauro Carvalho Chehab]

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 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: sta...@vger.kernel.org # For Kernel 4.18
Signed-off-by: Mauro Carvalho Chehab <mchehab+sams...@kernel.org>
---
 drivers/media/usb/dvb-usb-v2/dvbsky.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/media/usb/dvb-usb-v2/dvbsky.c 
b/drivers/media/usb/dvb-usb-v2/dvbsky.c
index 1aa88d94e57f..e28bd8836751 100644
--- 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 inbuilt IR receiver.");
 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 dvb_usb_device *d,
 
 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_device *d)
        if (ret)
                return ret;
        */
+       mutex_init(&state->stream_mutex);
+
        state->last_lock = 0;
 
        return 0;
-- 
2.17.1