| Message ID | Y72WBTUmh9r1lvKN@work (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [next] drm/i915/guc: Replace zero-length arrays with flexible-array members | expand |
On Tue, Jan 10, 2023 at 10:44:53AM -0600, Gustavo A. R. Silva wrote: > Zero-length arrays are deprecated[1] and we are moving towards > adopting C99 flexible-array members, instead. So, replace zero-length > arrays in a couple of structures (three, actually) with flex-array > members. > > 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 [2]. > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays [1] > Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [2] > Link: https://github.com/KSPP/linux/issues/78 > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> > --- > drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h b/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h > index 3624abfd22d1..9d589c28f40f 100644 > --- a/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h > +++ b/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h > @@ -73,7 +73,7 @@ struct guc_debug_capture_list_header { > > struct guc_debug_capture_list { > struct guc_debug_capture_list_header header; > - struct guc_mmio_reg regs[0]; > + struct guc_mmio_reg regs[]; > } __packed; > > /** > @@ -125,7 +125,7 @@ struct guc_state_capture_header_t { > > struct guc_state_capture_t { > struct guc_state_capture_header_t header; > - struct guc_mmio_reg mmio_entries[0]; > + struct guc_mmio_reg mmio_entries[]; > } __packed; > > enum guc_capture_group_types { > @@ -145,7 +145,7 @@ struct guc_state_capture_group_header_t { > /* this is the top level structure where an error-capture dump starts */ > struct guc_state_capture_group_t { > struct guc_state_capture_group_header_t grp_header; > - struct guc_state_capture_t capture_entries[0]; > + struct guc_state_capture_t capture_entries[]; Please notice we are currently using sizeof(struct ...). Along with your proposed changes, shouldn't we also start using the struct_size() which already take the flexible array into account? > } __packed; > > /** > -- > 2.34.1 >
On Tue, Jan 10, 2023 at 02:28:11PM -0500, Rodrigo Vivi wrote: > > On Tue, Jan 10, 2023 at 10:44:53AM -0600, Gustavo A. R. Silva wrote: > > Zero-length arrays are deprecated[1] and we are moving towards > > adopting C99 flexible-array members, instead. So, replace zero-length > > arrays in a couple of structures (three, actually) with flex-array > > members. > > > > 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 [2]. > > > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays [1] > > Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [2] > > Link: https://github.com/KSPP/linux/issues/78 > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> > > > --- > > drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h b/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h > > index 3624abfd22d1..9d589c28f40f 100644 > > --- a/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h > > +++ b/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h > > @@ -73,7 +73,7 @@ struct guc_debug_capture_list_header { > > > > struct guc_debug_capture_list { > > struct guc_debug_capture_list_header header; > > - struct guc_mmio_reg regs[0]; > > + struct guc_mmio_reg regs[]; > > } __packed; > > > > /** > > @@ -125,7 +125,7 @@ struct guc_state_capture_header_t { > > > > struct guc_state_capture_t { > > struct guc_state_capture_header_t header; > > - struct guc_mmio_reg mmio_entries[0]; > > + struct guc_mmio_reg mmio_entries[]; > > } __packed; > > > > enum guc_capture_group_types { > > @@ -145,7 +145,7 @@ struct guc_state_capture_group_header_t { > > /* this is the top level structure where an error-capture dump starts */ > > struct guc_state_capture_group_t { > > struct guc_state_capture_group_header_t grp_header; > > - struct guc_state_capture_t capture_entries[0]; > > + struct guc_state_capture_t capture_entries[]; > > Please notice we are currently using sizeof(struct ...). Yep; I noticed that. :) > Along with your proposed changes, shouldn't we also start using > the struct_size() which already take the flexible array into account? Not necessarily. In recent times, we don't include the struct_size changes in the same patch as the flex-array transformation. That's usually a follow-up patch. -- Gustavo
On Tue, Jan 10, 2023 at 01:42:57PM -0600, Gustavo A. R. Silva wrote: > On Tue, Jan 10, 2023 at 02:28:11PM -0500, Rodrigo Vivi wrote: > > > > On Tue, Jan 10, 2023 at 10:44:53AM -0600, Gustavo A. R. Silva wrote: > > > Zero-length arrays are deprecated[1] and we are moving towards > > > adopting C99 flexible-array members, instead. So, replace zero-length > > > arrays in a couple of structures (three, actually) with flex-array > > > members. > > > > > > 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 [2]. > > > > > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays [1] > > > Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [2] > > > Link: https://github.com/KSPP/linux/issues/78 > > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> > > > > > --- > > > drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h | 6 +++--- > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h b/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h > > > index 3624abfd22d1..9d589c28f40f 100644 > > > --- a/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h > > > +++ b/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h > > > @@ -73,7 +73,7 @@ struct guc_debug_capture_list_header { > > > > > > struct guc_debug_capture_list { > > > struct guc_debug_capture_list_header header; > > > - struct guc_mmio_reg regs[0]; > > > + struct guc_mmio_reg regs[]; > > > } __packed; > > > > > > /** > > > @@ -125,7 +125,7 @@ struct guc_state_capture_header_t { > > > > > > struct guc_state_capture_t { > > > struct guc_state_capture_header_t header; > > > - struct guc_mmio_reg mmio_entries[0]; > > > + struct guc_mmio_reg mmio_entries[]; > > > } __packed; > > > > > > enum guc_capture_group_types { > > > @@ -145,7 +145,7 @@ struct guc_state_capture_group_header_t { > > > /* this is the top level structure where an error-capture dump starts */ > > > struct guc_state_capture_group_t { > > > struct guc_state_capture_group_header_t grp_header; > > > - struct guc_state_capture_t capture_entries[0]; > > > + struct guc_state_capture_t capture_entries[]; > > > > Please notice we are currently using sizeof(struct ...). > > Yep; I noticed that. :) > > > Along with your proposed changes, shouldn't we also start using > > the struct_size() which already take the flexible array into account? > > Not necessarily. In recent times, we don't include the struct_size > changes in the same patch as the flex-array transformation. That's > usually a follow-up patch. okay, if that's not a problem, let's go with this for now and wait for the follow ups. Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> (and pushing it right now. Thanks for the patch) > > -- > Gustavo
diff --git a/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h b/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h index 3624abfd22d1..9d589c28f40f 100644 --- a/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h +++ b/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h @@ -73,7 +73,7 @@ struct guc_debug_capture_list_header { struct guc_debug_capture_list { struct guc_debug_capture_list_header header; - struct guc_mmio_reg regs[0]; + struct guc_mmio_reg regs[]; } __packed; /** @@ -125,7 +125,7 @@ struct guc_state_capture_header_t { struct guc_state_capture_t { struct guc_state_capture_header_t header; - struct guc_mmio_reg mmio_entries[0]; + struct guc_mmio_reg mmio_entries[]; } __packed; enum guc_capture_group_types { @@ -145,7 +145,7 @@ struct guc_state_capture_group_header_t { /* this is the top level structure where an error-capture dump starts */ struct guc_state_capture_group_t { struct guc_state_capture_group_header_t grp_header; - struct guc_state_capture_t capture_entries[0]; + struct guc_state_capture_t capture_entries[]; } __packed; /**
Zero-length arrays are deprecated[1] and we are moving towards adopting C99 flexible-array members, instead. So, replace zero-length arrays in a couple of structures (three, actually) with flex-array members. 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 [2]. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays [1] Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [2] Link: https://github.com/KSPP/linux/issues/78 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)