From c4a98793a63c423c9e1af51822325969e23c16d4 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 18 Nov 2008 14:51:08 -0300 Subject: [PATCH] V4L/DVB (9646): em28xx: avoid allocating/dealocating memory on every control urb Before this patch, every register setup on em28xx were dynamically allocating a temporary buffer for control URB's to be handled. To avoid this ping-pong, use, instead a pre-allocated buffer. Also, be sure that read control URB's also use the buffer, instead of relying on a stack buffer. Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/em28xx/em28xx-core.c | 48 +++++++++++++----------- drivers/media/video/em28xx/em28xx.h | 5 +++ 2 files changed, 31 insertions(+), 22 deletions(-) diff --git a/drivers/media/video/em28xx/em28xx-core.c b/drivers/media/video/em28xx/em28xx-core.c index 038da614a734..9551b8ab8c44 100644 --- a/drivers/media/video/em28xx/em28xx-core.c +++ b/drivers/media/video/em28xx/em28xx-core.c @@ -69,19 +69,29 @@ int em28xx_read_reg_req_len(struct em28xx *dev, u8 req, u16 reg, int ret, byte; if (dev->state & DEV_DISCONNECTED) - return(-ENODEV); + return -ENODEV; + + if (len > URB_MAX_CTRL_SIZE) + return -EINVAL; em28xx_regdbg("req=%02x, reg=%02x ", req, reg); ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), req, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, - 0x0000, reg, buf, len, HZ); + 0x0000, reg, dev->urb_buf, len, HZ); + if (ret < 0) { + if (reg_debug) + printk(" failed!\n"); + return ret; + } + + if (len) + memcpy(buf, dev->urb_buf, len); if (reg_debug) { - printk(ret < 0 ? " failed!\n" : "%02x values: ", ret); + printk("%02x values: ", ret); for (byte = 0; byte < len; byte++) printk(" %02x", (unsigned char)buf[byte]); - printk("\n"); } @@ -104,14 +114,16 @@ int em28xx_read_reg_req(struct em28xx *dev, u8 req, u16 reg) ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), req, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, - 0x0000, reg, &val, 1, HZ); + 0x0000, reg, dev->urb_buf, 1, HZ); + if (ret < 0) { + printk(" failed!\n"); + return ret; + } - if (reg_debug) - printk(ret < 0 ? " failed!\n" : - "%02x\n", (unsigned char) val); + val = dev->urb_buf[0]; - if (ret < 0) - return ret; + if (reg_debug) + printk("%02x\n", (unsigned char) val); return val; } @@ -130,19 +142,13 @@ int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 reg, char *buf, { int ret; - /*usb_control_msg seems to expect a kmalloced buffer */ - unsigned char *bufs; - if (dev->state & DEV_DISCONNECTED) return -ENODEV; - if (len < 1) + if ((len < 1) || (len > URB_MAX_CTRL_SIZE)) return -EINVAL; - bufs = kmalloc(len, GFP_KERNEL); - em28xx_regdbg("req=%02x reg=%02x:", req, reg); - if (reg_debug) { int i; for (i = 0; i < len; ++i) @@ -150,16 +156,14 @@ int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 reg, char *buf, printk("\n"); } - if (!bufs) - return -ENOMEM; - memcpy(bufs, buf, len); + 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, bufs, len, HZ); + 0x0000, reg, dev->urb_buf, len, HZ); + if (dev->wait_after_write) msleep(dev->wait_after_write); - kfree(bufs); return ret; } diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h index 82781178e0a3..1adf3d9d9bff 100644 --- a/drivers/media/video/em28xx/em28xx.h +++ b/drivers/media/video/em28xx/em28xx.h @@ -102,6 +102,9 @@ #define EM28XX_MIN_BUF 4 #define EM28XX_DEF_BUF 8 +/*Limits the max URB message size */ +#define URB_MAX_CTRL_SIZE 80 + /* Params for validated field */ #define EM28XX_BOARD_NOT_VALIDATED 1 #define EM28XX_BOARD_VALIDATED 0 @@ -451,6 +454,8 @@ struct em28xx { unsigned int *alt_max_pkt_size; /* array of wMaxPacketSize */ struct urb *urb[EM28XX_NUM_BUFS]; /* urb for isoc transfers */ char *transfer_buffer[EM28XX_NUM_BUFS]; /* transfer buffers for isoc transfer */ + char urb_buf[URB_MAX_CTRL_SIZE]; /* urb control msg buffer */ + /* helper funcs that call usb_control_msg */ int (*em28xx_write_regs) (struct em28xx *dev, u16 reg, char *buf, int len); -- 2.39.2