Andy, Thanks for your patch. Although I am not familiar with the voodoo programming, it looks good for me. Reviewed-by: Bingbu Cao <bingbu.cao@xxxxxxxxx> ________________________ BRs, Bingbu Cao > -----Original Message----- > From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > Sent: Tuesday, July 26, 2022 8:06 PM > To: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>; linux- > media@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Cc: Qiu, Tian Shu <tian.shu.qiu@xxxxxxxxx>; Tu, ShawnX > <shawnx.tu@xxxxxxxxx>; Cao, Bingbu <bingbu.cao@xxxxxxxxx>; Mauro Carvalho > Chehab <mchehab@xxxxxxxxxx> > Subject: [PATCH v1 2/8] media: ov2740: Replace voodoo coding with > understandle flow > > Besides not being understandable at the first glance, the code might > provoke a compiler or a static analyser tool to warn about out-of-bound > access (when len == 0). > > Replace it with clear flow an understandable intention. > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > --- > drivers/media/i2c/ov2740.c | 28 +++++++++++++++++++++++----- > 1 file changed, 23 insertions(+), 5 deletions(-) > > diff --git a/drivers/media/i2c/ov2740.c b/drivers/media/i2c/ov2740.c index > c975db1bbe8c..81c0ab220339 100644 > --- a/drivers/media/i2c/ov2740.c > +++ b/drivers/media/i2c/ov2740.c > @@ -377,10 +377,10 @@ static int ov2740_read_reg(struct ov2740 *ov2740, > u16 reg, u16 len, u32 *val) > struct i2c_client *client = v4l2_get_subdevdata(&ov2740->sd); > struct i2c_msg msgs[2]; > u8 addr_buf[2]; > - u8 data_buf[4] = {0}; > + u8 data_buf[4]; > int ret = 0; > > - if (len > sizeof(data_buf)) > + if (len > 4) > return -EINVAL; > > put_unaligned_be16(reg, addr_buf); > @@ -391,13 +391,22 @@ static int ov2740_read_reg(struct ov2740 *ov2740, > u16 reg, u16 len, u32 *val) > msgs[1].addr = client->addr; > msgs[1].flags = I2C_M_RD; > msgs[1].len = len; > - msgs[1].buf = &data_buf[sizeof(data_buf) - len]; > + msgs[1].buf = data_buf; > > ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); > if (ret != ARRAY_SIZE(msgs)) > return ret < 0 ? ret : -EIO; > > - *val = get_unaligned_be32(data_buf); > + if (len == 4) > + *val = get_unaligned_be32(data_buf); > + else if (len == 3) > + *val = get_unaligned_be24(data_buf); > + else if (len == 2) > + *val = get_unaligned_be16(data_buf); > + else if (len == 1) > + *val = data_buf[0]; > + else > + return -EINVAL; > > return 0; > } > @@ -412,7 +421,16 @@ static int ov2740_write_reg(struct ov2740 *ov2740, > u16 reg, u16 len, u32 val) > return -EINVAL; > > put_unaligned_be16(reg, buf); > - put_unaligned_be32(val << 8 * (4 - len), buf + 2); > + if (len == 4) > + put_unaligned_be32(val, buf + 2); > + else if (len == 3) > + put_unaligned_be24(val, buf + 2); > + else if (len == 2) > + put_unaligned_be16(val, buf + 2); > + else if (len == 1) > + buf[2] = val; > + else > + return -EINVAL; > > ret = i2c_master_send(client, buf, len + 2); > if (ret != len + 2) > -- > 2.35.1