On Mon, Nov 19, 2018 at 08:44:49AM -0800, Tadeusz Struk wrote: > On 11/19/18 5:58 AM, Jarkko Sakkinen wrote: > > Please explain a scenario where "!ret_size" would no work given that > > both size and partial_data have always positive value? > > Right, I only looked at the one line above before responding. > I'll change it to !ret_size > > > > > I don't understand. In order to maintain backwards compatibility you can > > send a new command at any time. > > No, currently it is not possible to send a new command until the previous > response is consumed. -EBUSY is returned if one sends a new command before > reading the previous response (or at least part of it). See: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/char/tpm/tpm-dev-common.c#n128 Ah, you are correct. You should add a boolean flag instead of introducing a new variable for holding amount that has been read because obviously one read operation is enough for backwards compatibility. The code could read the code to data_pending and then set priv->data_read = false; We do not need the original amount for anything. /Jarkko
