| Message ID | ZGVlcpuvx1rSOMP8@work |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [next] ALSA: mixart: Replace one-element arrays with simple object declarations | expand |
On Thu, 18 May 2023 01:38:26 +0200, Gustavo A. R. Silva wrote: > > One-element arrays are deprecated, and we are replacing them with flexible > array members, instead. However, in this case it seems those one-element > arrays have never actually been used as fake flexible arrays. > > See this code that dates from Linux-2.6.12-rc2 initial git repository build > (commit 1da177e4c3f4 ("Linux-2.6.12-rc2")): > > sound/pci/mixart/mixart_core.h: > 215 struct mixart_stream_state_req > 216 { > 217 u32 delayed; > 218 u64 scheduler; > 219 u32 reserved4np[3]; > 220 u32 stream_count; /* set to 1 for instance */ > 221 struct mixart_flow_info stream_info; /* could be an array[stream_cou nt] */ > 222 } __attribute__((packed)); > > sound/pci/mixart/mixart.c: > 388 > 389 memset(&stream_state_req, 0, sizeof(stream_state_req)); > 390 stream_state_req.stream_count = 1; > 391 stream_state_req.stream_info.stream_desc.uid_pipe = stream->pipe->group_uid; > 392 stream_state_req.stream_info.stream_desc.stream_idx = stream->substream->number; > 393 > > So, taking the code above as example, replace multiple one-element > arrays with simple object declarations, and refactor the rest of the > code, accordingly. > > This helps with the ongoing efforts to tighten the FORTIFY_SOURCE > routines on memcpy() and help us make progress towards globally > enabling -fstrict-flex-arrays=3 [1]. > > This results in no differences in binary output. > > Link: https://github.com/KSPP/linux/issues/79 > Link: https://github.com/KSPP/linux/issues/296 > Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1] > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Replacing with a simple object itself is OK, but please keep the comment; the statement there is still valid, as it could be rather a multi-member array in theory. thanks, Takashi > --- > sound/pci/mixart/mixart.c | 8 ++++---- > sound/pci/mixart/mixart_core.h | 7 +++---- > 2 files changed, 7 insertions(+), 8 deletions(-) > > diff --git a/sound/pci/mixart/mixart.c b/sound/pci/mixart/mixart.c > index 1b078b789604..7ceaf6a7a77e 100644 > --- a/sound/pci/mixart/mixart.c > +++ b/sound/pci/mixart/mixart.c > @@ -98,7 +98,7 @@ static int mixart_set_pipe_state(struct mixart_mgr *mgr, > > memset(&group_state, 0, sizeof(group_state)); > group_state.pipe_count = 1; > - group_state.pipe_uid[0] = pipe->group_uid; > + group_state.pipe_uid = pipe->group_uid; > > if(start) > request.message_id = MSG_STREAM_START_STREAM_GRP_PACKET; > @@ -185,7 +185,7 @@ static int mixart_set_clock(struct mixart_mgr *mgr, > clock_properties.clock_mode = CM_STANDALONE; > clock_properties.frequency = rate; > clock_properties.nb_callers = 1; /* only one entry in uid_caller ! */ > - clock_properties.uid_caller[0] = pipe->group_uid; > + clock_properties.uid_caller = pipe->group_uid; > > dev_dbg(&mgr->pci->dev, "mixart_set_clock to %d kHz\n", rate); > > @@ -565,8 +565,8 @@ static int mixart_set_format(struct mixart_stream *stream, snd_pcm_format_t form > > stream_param.pipe_count = 1; /* set to 1 */ > stream_param.stream_count = 1; /* set to 1 */ > - stream_param.stream_desc[0].uid_pipe = stream->pipe->group_uid; > - stream_param.stream_desc[0].stream_idx = stream->substream->number; > + stream_param.stream_desc.uid_pipe = stream->pipe->group_uid; > + stream_param.stream_desc.stream_idx = stream->substream->number; > > request.message_id = MSG_STREAM_SET_INPUT_STAGE_PARAM; > request.uid = (struct mixart_uid){0,0}; > diff --git a/sound/pci/mixart/mixart_core.h b/sound/pci/mixart/mixart_core.h > index 2f0e29ed5d63..ac74b2133c97 100644 > --- a/sound/pci/mixart/mixart_core.h > +++ b/sound/pci/mixart/mixart_core.h > @@ -231,7 +231,7 @@ struct mixart_group_state_req > u64 scheduler; > u32 reserved4np[2]; > u32 pipe_count; /* set to 1 for instance */ > - struct mixart_uid pipe_uid[1]; /* could be an array[pipe_count] */ > + struct mixart_uid pipe_uid; > } __attribute__((packed)); > > struct mixart_group_state_resp > @@ -314,7 +314,7 @@ struct mixart_clock_properties > u32 format; > u32 board_mask; > u32 nb_callers; /* set to 1 (see below) */ > - struct mixart_uid uid_caller[1]; > + struct mixart_uid uid_caller; > } __attribute__((packed)); > > struct mixart_clock_properties_resp > @@ -401,8 +401,7 @@ struct mixart_stream_param_desc > u32 reserved4np[3]; > u32 pipe_count; /* set to 1 (array size !) */ > u32 stream_count; /* set to 1 (array size !) */ > - struct mixart_txx_stream_desc stream_desc[1]; /* only one stream per command, but this could be an array */ > - > + struct mixart_txx_stream_desc stream_desc; > } __attribute__((packed)); > > > -- > 2.34.1 >
diff --git a/sound/pci/mixart/mixart.c b/sound/pci/mixart/mixart.c index 1b078b789604..7ceaf6a7a77e 100644 --- a/sound/pci/mixart/mixart.c +++ b/sound/pci/mixart/mixart.c @@ -98,7 +98,7 @@ static int mixart_set_pipe_state(struct mixart_mgr *mgr, memset(&group_state, 0, sizeof(group_state)); group_state.pipe_count = 1; - group_state.pipe_uid[0] = pipe->group_uid; + group_state.pipe_uid = pipe->group_uid; if(start) request.message_id = MSG_STREAM_START_STREAM_GRP_PACKET; @@ -185,7 +185,7 @@ static int mixart_set_clock(struct mixart_mgr *mgr, clock_properties.clock_mode = CM_STANDALONE; clock_properties.frequency = rate; clock_properties.nb_callers = 1; /* only one entry in uid_caller ! */ - clock_properties.uid_caller[0] = pipe->group_uid; + clock_properties.uid_caller = pipe->group_uid; dev_dbg(&mgr->pci->dev, "mixart_set_clock to %d kHz\n", rate); @@ -565,8 +565,8 @@ static int mixart_set_format(struct mixart_stream *stream, snd_pcm_format_t form stream_param.pipe_count = 1; /* set to 1 */ stream_param.stream_count = 1; /* set to 1 */ - stream_param.stream_desc[0].uid_pipe = stream->pipe->group_uid; - stream_param.stream_desc[0].stream_idx = stream->substream->number; + stream_param.stream_desc.uid_pipe = stream->pipe->group_uid; + stream_param.stream_desc.stream_idx = stream->substream->number; request.message_id = MSG_STREAM_SET_INPUT_STAGE_PARAM; request.uid = (struct mixart_uid){0,0}; diff --git a/sound/pci/mixart/mixart_core.h b/sound/pci/mixart/mixart_core.h index 2f0e29ed5d63..ac74b2133c97 100644 --- a/sound/pci/mixart/mixart_core.h +++ b/sound/pci/mixart/mixart_core.h @@ -231,7 +231,7 @@ struct mixart_group_state_req u64 scheduler; u32 reserved4np[2]; u32 pipe_count; /* set to 1 for instance */ - struct mixart_uid pipe_uid[1]; /* could be an array[pipe_count] */ + struct mixart_uid pipe_uid; } __attribute__((packed)); struct mixart_group_state_resp @@ -314,7 +314,7 @@ struct mixart_clock_properties u32 format; u32 board_mask; u32 nb_callers; /* set to 1 (see below) */ - struct mixart_uid uid_caller[1]; + struct mixart_uid uid_caller; } __attribute__((packed)); struct mixart_clock_properties_resp @@ -401,8 +401,7 @@ struct mixart_stream_param_desc u32 reserved4np[3]; u32 pipe_count; /* set to 1 (array size !) */ u32 stream_count; /* set to 1 (array size !) */ - struct mixart_txx_stream_desc stream_desc[1]; /* only one stream per command, but this could be an array */ - + struct mixart_txx_stream_desc stream_desc; } __attribute__((packed));
One-element arrays are deprecated, and we are replacing them with flexible array members, instead. However, in this case it seems those one-element arrays have never actually been used as fake flexible arrays. See this code that dates from Linux-2.6.12-rc2 initial git repository build (commit 1da177e4c3f4 ("Linux-2.6.12-rc2")): sound/pci/mixart/mixart_core.h: 215 struct mixart_stream_state_req 216 { 217 u32 delayed; 218 u64 scheduler; 219 u32 reserved4np[3]; 220 u32 stream_count; /* set to 1 for instance */ 221 struct mixart_flow_info stream_info; /* could be an array[stream_cou nt] */ 222 } __attribute__((packed)); sound/pci/mixart/mixart.c: 388 389 memset(&stream_state_req, 0, sizeof(stream_state_req)); 390 stream_state_req.stream_count = 1; 391 stream_state_req.stream_info.stream_desc.uid_pipe = stream->pipe->group_uid; 392 stream_state_req.stream_info.stream_desc.stream_idx = stream->substream->number; 393 So, taking the code above as example, replace multiple one-element arrays with simple object declarations, and refactor the rest of the code, accordingly. This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines on memcpy() and help us make progress towards globally enabling -fstrict-flex-arrays=3 [1]. This results in no differences in binary output. Link: https://github.com/KSPP/linux/issues/79 Link: https://github.com/KSPP/linux/issues/296 Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1] Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- sound/pci/mixart/mixart.c | 8 ++++---- sound/pci/mixart/mixart_core.h | 7 +++---- 2 files changed, 7 insertions(+), 8 deletions(-)