Hi, On Tue, May 19, 2020 at 07:34:25PM +0200, Oscar Carter wrote: > In an effort to enable -Wcast-function-type in the top-level Makefile to > support Control Flow Integrity builds, remove all the function callback > casts. > > To do this, modify the "fw_iso_context_create" function prototype adding > a new parameter for the multichannel callback. Also, fix all the > function calls accordingly. > > In the "fw_iso_context_create" function return an error code if both > callback parameters are NULL and also set the "ctx->callback.sc" > explicity to NULL in this case. It is not necessary set to NULL the > "ctx->callback.mc" variable because this and "ctx->callback.sc" are an > union and setting one implies setting the other one to the same value. > > Signed-off-by: Oscar Carter <oscar.carter@xxxxxxx> > --- > Changelog v1->v2 > -Set explicity to NULL the "ctx->callback.sc" variable and return an error > code in "fw_iso_context_create" function if both callback parameters are > NULL as Lev R. Oshvang suggested. > -Modify the commit changelog accordingly. > > drivers/firewire/core-cdev.c | 12 +++++++----- > drivers/firewire/core-iso.c | 14 ++++++++++++-- > drivers/firewire/net.c | 2 +- > drivers/media/firewire/firedtv-fw.c | 3 ++- > include/linux/firewire.h | 3 ++- > sound/firewire/amdtp-stream.c | 2 +- > sound/firewire/isight.c | 4 ++-- > 7 files changed, 27 insertions(+), 13 deletions(-) I'm an author of ALSA firewire stack and thanks for the patch. I agree with your intention to remove the cast of function callback toward CFI build. Practically, the isochronous context with FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL is never used by in-kernel drivers. Here, I propose to leave current kernel API (fw_iso_context_create() with fw_iso_callback_t) as is. Alternatively, a new kernel API for the context (e.g. fw_iso_mc_context_create() with fw_iso_mc_callback_t). This idea leaves current drivers as is and the change is done inner firewire-core driver, therefore existent kernel API is not changed. Later I post two patches for the proposal. I'd like you to review it and I'm glad to receive your comments. Regards Takashi Sakamoto
