On 2017-11-28, at 17:15:24 +0300, Dan Carpenter wrote:
> On Mon, Nov 27, 2017 at 12:44:48PM +0000, Jeremy Sowden wrote:
> > The "address" member of struct ia_css_host_data is a
> > pointer-to-char, so define default as NULL.
> >
> > --- a/drivers/staging/media/atomisp/pci/atomisp2/css2400/runtime/isp_param/interface/ia_css_isp_param_types.h
> > +++ b/drivers/staging/media/atomisp/pci/atomisp2/css2400/runtime/isp_param/interface/ia_css_isp_param_types.h
> > @@ -95,7 +95,7 @@ union ia_css_all_memory_offsets {
> > };
> >
> > #define IA_CSS_DEFAULT_ISP_MEM_PARAMS \
> > - { { { { 0, 0 } } } }
> > + { { { { NULL, 0 } } } }
>
> This define is way ugly and instead of making superficial changes, you
> should try to eliminate it.
>
> People look at warnings as a bad thing but they are actually a
> valuable resource which call attention to bad code. By making this
> change you're kind of wasting the warning. The bad code is still
> there, it's just swept under the rug but like a dead mouse carcass
> it's still stinking up the living room. We should leave the warning
> there until it irritates someone enough to fix it properly.
Tracking down the offending initializer was definitely a pain.
Compound literals with designated initializers would make this macro
(and a number of others) easier to understand and more type-safe:
#define IA_CSS_DEFAULT_ISP_MEM_PARAMS \
- { { { { 0, 0 } } } }
+ (struct ia_css_isp_param_host_segments) { \
+ .params = { { \
+ (struct ia_css_host_data) { \
+ .address = NULL, \
+ .size = 0 \
+ } \
+ } } \
+ }
Unfortunately this default value is one end of a chain of default values
used to initialize members of default values of enclosing structs where
the outermost values are used to initialize some static variables:
static enum ia_css_err
init_pipe_defaults(enum ia_css_pipe_mode mode,
struct ia_css_pipe *pipe,
bool copy_pipe)
{
static struct ia_css_pipe default_pipe = IA_CSS_DEFAULT_PIPE;
static struct ia_css_preview_settings prev = IA_CSS_DEFAULT_PREVIEW_SETTINGS;
static struct ia_css_capture_settings capt = IA_CSS_DEFAULT_CAPTURE_SETTINGS;
static struct ia_css_video_settings video = IA_CSS_DEFAULT_VIDEO_SETTINGS;
static struct ia_css_yuvpp_settings yuvpp = IA_CSS_DEFAULT_YUVPP_SETTINGS;
if (pipe == NULL) {
IA_CSS_ERROR("NULL pipe parameter");
return IA_CSS_ERR_INVALID_ARGUMENTS;
}
/* Initialize pipe to pre-defined defaults */
*pipe = default_pipe;
/* TODO: JB should not be needed, but temporary backward reference */
switch (mode) {
case IA_CSS_PIPE_MODE_PREVIEW:
pipe->mode = IA_CSS_PIPE_ID_PREVIEW;
pipe->pipe_settings.preview = prev;
break;
case IA_CSS_PIPE_MODE_CAPTURE:
if (copy_pipe) {
pipe->mode = IA_CSS_PIPE_ID_COPY;
} else {
pipe->mode = IA_CSS_PIPE_ID_CAPTURE;
}
pipe->pipe_settings.capture = capt;
break;
case IA_CSS_PIPE_MODE_VIDEO:
pipe->mode = IA_CSS_PIPE_ID_VIDEO;
pipe->pipe_settings.video = video;
break;
case IA_CSS_PIPE_MODE_ACC:
pipe->mode = IA_CSS_PIPE_ID_ACC;
break;
case IA_CSS_PIPE_MODE_COPY:
pipe->mode = IA_CSS_PIPE_ID_CAPTURE;
break;
case IA_CSS_PIPE_MODE_YUVPP:
pipe->mode = IA_CSS_PIPE_ID_YUVPP;
pipe->pipe_settings.yuvpp = yuvpp;
break;
default:
return IA_CSS_ERR_INVALID_ARGUMENTS;
}
return IA_CSS_SUCCESS;
}
and GCC's limited support for using compound literals to initialize
static variables doesn't stretch this far.
I'm not convinced, however, that those variables actually achieve very
much. If I change the code to assign the defaults directly, the problem
goes away:
diff --git a/drivers/staging/media/atomisp/pci/atomisp2/css2400/sh_css.c b/drivers/staging/media/atomisp/pci/atomisp2/css2400/sh_css.c
index f92b6a9f77eb..671b2c732a46 100644
--- a/drivers/staging/media/atomisp/pci/atomisp2/css2400/sh_css.c
+++ b/drivers/staging/media/atomisp/pci/atomisp2/css2400/sh_css.c
@@ -2291,25 +2291,19 @@ init_pipe_defaults(enum ia_css_pipe_mode mode,
struct ia_css_pipe *pipe,
bool copy_pipe)
{
- static struct ia_css_pipe default_pipe = IA_CSS_DEFAULT_PIPE;
- static struct ia_css_preview_settings prev = IA_CSS_DEFAULT_PREVIEW_SETTINGS;
- static struct ia_css_capture_settings capt = IA_CSS_DEFAULT_CAPTURE_SETTINGS;
- static struct ia_css_video_settings video = IA_CSS_DEFAULT_VIDEO_SETTINGS;
- static struct ia_css_yuvpp_settings yuvpp = IA_CSS_DEFAULT_YUVPP_SETTINGS;
-
if (pipe == NULL) {
IA_CSS_ERROR("NULL pipe parameter");
return IA_CSS_ERR_INVALID_ARGUMENTS;
}
/* Initialize pipe to pre-defined defaults */
- *pipe = default_pipe;
+ *pipe = IA_CSS_DEFAULT_PIPE;
/* TODO: JB should not be needed, but temporary backward reference */
switch (mode) {
case IA_CSS_PIPE_MODE_PREVIEW:
pipe->mode = IA_CSS_PIPE_ID_PREVIEW;
- pipe->pipe_settings.preview = prev;
+ pipe->pipe_settings.preview = IA_CSS_DEFAULT_PREVIEW_SETTINGS;
break;
case IA_CSS_PIPE_MODE_CAPTURE:
if (copy_pipe) {
@@ -2317,11 +2311,11 @@ init_pipe_defaults(enum ia_css_pipe_mode mode,
} else {
pipe->mode = IA_CSS_PIPE_ID_CAPTURE;
}
- pipe->pipe_settings.capture = capt;
+ pipe->pipe_settings.capture = IA_CSS_DEFAULT_CAPTURE_SETTINGS;
break;
case IA_CSS_PIPE_MODE_VIDEO:
pipe->mode = IA_CSS_PIPE_ID_VIDEO;
- pipe->pipe_settings.video = video;
+ pipe->pipe_settings.video = IA_CSS_DEFAULT_VIDEO_SETTINGS;
break;
case IA_CSS_PIPE_MODE_ACC:
pipe->mode = IA_CSS_PIPE_ID_ACC;
@@ -2331,7 +2325,7 @@ init_pipe_defaults(enum ia_css_pipe_mode mode,
break;
case IA_CSS_PIPE_MODE_YUVPP:
pipe->mode = IA_CSS_PIPE_ID_YUVPP;
- pipe->pipe_settings.yuvpp = yuvpp;
+ pipe->pipe_settings.yuvpp = IA_CSS_DEFAULT_YUVPP_SETTINGS;
break;
default:
return IA_CSS_ERR_INVALID_ARGUMENTS;
Does this seem reasonable or am I barking up the wrong tree?
J.
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