> But now when I try to use it I'm not exicted when the buffer is bounced
> but we fail to map the buffer with the DMA APIs. For an I2C_M_RD

Yes, this was reported before and the function to unmap looks different
now as of v4.19-rc2...

> the buffer that we setup. Or we can pass an argument to
> i2c_release_dma_safe_msg_buf() to indicate if we should do the memcpy or
> not?

... exactly like this :)