From f2a2e4910502e866833732f31ee697d15b3e56fd Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Wed, 19 Nov 2008 06:17:44 -0300 Subject: [PATCH] V4L/DVB (9647): em28xx: void having two concurrent control URB's Now that we have a polling task for IR, there's a race condition, since IR can be polling while other operations are being doing. Also, we are now sharing the same urb_buf for both read and write control urb operations. So, we need a mutex. Thanks to Davin Heitmueller for warning me. Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/em28xx/em28xx-core.c | 12 ++++++++++-- drivers/media/video/em28xx/em28xx-video.c | 1 + drivers/media/video/em28xx/em28xx.h | 1 + 3 files changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/media/video/em28xx/em28xx-core.c b/drivers/media/video/em28xx/em28xx-core.c index 9551b8ab8c4..15e2b525310 100644 --- a/drivers/media/video/em28xx/em28xx-core.c +++ b/drivers/media/video/em28xx/em28xx-core.c @@ -76,18 +76,22 @@ int em28xx_read_reg_req_len(struct em28xx *dev, u8 req, u16 reg, em28xx_regdbg("req=%02x, reg=%02x ", req, reg); + mutex_lock(&dev->ctrl_urb_lock); ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), req, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, 0x0000, reg, dev->urb_buf, len, HZ); if (ret < 0) { if (reg_debug) printk(" failed!\n"); + mutex_unlock(&dev->ctrl_urb_lock); return ret; } if (len) memcpy(buf, dev->urb_buf, len); + mutex_unlock(&dev->ctrl_urb_lock); + if (reg_debug) { printk("%02x values: ", ret); for (byte = 0; byte < len; byte++) @@ -112,16 +116,18 @@ int em28xx_read_reg_req(struct em28xx *dev, u8 req, u16 reg) em28xx_regdbg("req=%02x, reg=%02x:", req, reg); + mutex_lock(&dev->ctrl_urb_lock); ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), req, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, 0x0000, reg, dev->urb_buf, 1, HZ); + val = dev->urb_buf[0]; + mutex_unlock(&dev->ctrl_urb_lock); + if (ret < 0) { printk(" failed!\n"); return ret; } - val = dev->urb_buf[0]; - if (reg_debug) printk("%02x\n", (unsigned char) val); @@ -156,10 +162,12 @@ int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 reg, char *buf, printk("\n"); } + mutex_lock(&dev->ctrl_urb_lock); memcpy(dev->urb_buf, buf, len); ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0), req, USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE, 0x0000, reg, dev->urb_buf, len, HZ); + mutex_unlock(&dev->ctrl_urb_lock); if (dev->wait_after_write) msleep(dev->wait_after_write); diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c index bca5955339b..c32fc7d24a4 100644 --- a/drivers/media/video/em28xx/em28xx-video.c +++ b/drivers/media/video/em28xx/em28xx-video.c @@ -1936,6 +1936,7 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev, dev->udev = udev; mutex_init(&dev->lock); + mutex_init(&dev->ctrl_urb_lock); spin_lock_init(&dev->slock); init_waitqueue_head(&dev->open); init_waitqueue_head(&dev->wait_frame); diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h index 1adf3d9d9bf..5956e9b3062 100644 --- a/drivers/media/video/em28xx/em28xx.h +++ b/drivers/media/video/em28xx/em28xx.h @@ -433,6 +433,7 @@ struct em28xx { /* locks */ struct mutex lock; + struct mutex ctrl_urb_lock; /* protects urb_buf */ /* spinlock_t queue_lock; */ struct list_head inqueue, outqueue; wait_queue_head_t open, wait_frame, wait_stream; -- 2.41.0