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    Subject[PATCH 3.12 188/212] media: af9035: Dont use dynamic static allocation
    Date
    3.12-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Mauro Carvalho Chehab <m.chehab@samsung.com>

    commit 7760e148350bf6df95662bc0db3734e9d991cb03 upstream.

    Dynamic static allocation is evil, as Kernel stack is too low, and
    compilation complains about it on some archs:
    drivers/media/usb/dvb-usb-v2/af9035.c:142:1: warning: 'af9035_wr_regs' uses dynamic stack allocation [enabled by default]
    drivers/media/usb/dvb-usb-v2/af9035.c:305:1: warning: 'af9035_i2c_master_xfer' uses dynamic stack allocation [enabled by default]
    Instead, let's enforce a limit for the buffer to be the max size of
    a control URB payload data (64 bytes).

    Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
    Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
    Reviewed-by: Antti Palosaari <crope@iki.fi>
    Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/media/usb/dvb-usb-v2/af9035.c | 29 ++++++++++++++++++++++++++---
    1 file changed, 26 insertions(+), 3 deletions(-)

    --- a/drivers/media/usb/dvb-usb-v2/af9035.c
    +++ b/drivers/media/usb/dvb-usb-v2/af9035.c
    @@ -21,6 +21,9 @@

    #include "af9035.h"

    +/* Max transfer size done by I2C transfer functions */
    +#define MAX_XFER_SIZE 64
    +
    DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);

    static u16 af9035_checksum(const u8 *buf, size_t len)
    @@ -126,10 +129,16 @@ exit:
    /* write multiple registers */
    static int af9035_wr_regs(struct dvb_usb_device *d, u32 reg, u8 *val, int len)
    {
    - u8 wbuf[6 + len];
    + u8 wbuf[MAX_XFER_SIZE];
    u8 mbox = (reg >> 16) & 0xff;
    struct usb_req req = { CMD_MEM_WR, mbox, sizeof(wbuf), wbuf, 0, NULL };

    + if (6 + len > sizeof(wbuf)) {
    + dev_warn(&d->udev->dev, "%s: i2c wr: len=%d is too big!\n",
    + KBUILD_MODNAME, len);
    + return -EOPNOTSUPP;
    + }
    +
    wbuf[0] = len;
    wbuf[1] = 2;
    wbuf[2] = 0;
    @@ -228,9 +237,16 @@ static int af9035_i2c_master_xfer(struct
    msg[1].len);
    } else {
    /* I2C */
    - u8 buf[5 + msg[0].len];
    + u8 buf[MAX_XFER_SIZE];
    struct usb_req req = { CMD_I2C_RD, 0, sizeof(buf),
    buf, msg[1].len, msg[1].buf };
    +
    + if (5 + msg[0].len > sizeof(buf)) {
    + dev_warn(&d->udev->dev,
    + "%s: i2c xfer: len=%d is too big!\n",
    + KBUILD_MODNAME, msg[0].len);
    + return -EOPNOTSUPP;
    + }
    req.mbox |= ((msg[0].addr & 0x80) >> 3);
    buf[0] = msg[1].len;
    buf[1] = msg[0].addr << 1;
    @@ -257,9 +273,16 @@ static int af9035_i2c_master_xfer(struct
    msg[0].len - 3);
    } else {
    /* I2C */
    - u8 buf[5 + msg[0].len];
    + u8 buf[MAX_XFER_SIZE];
    struct usb_req req = { CMD_I2C_WR, 0, sizeof(buf), buf,
    0, NULL };
    +
    + if (5 + msg[0].len > sizeof(buf)) {
    + dev_warn(&d->udev->dev,
    + "%s: i2c xfer: len=%d is too big!\n",
    + KBUILD_MODNAME, msg[0].len);
    + return -EOPNOTSUPP;
    + }
    req.mbox |= ((msg[0].addr & 0x80) >> 3);
    buf[0] = msg[0].len;
    buf[1] = msg[0].addr << 1;



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