media: ccs: Make (non-)use of uninitialised variables more robust

GCC with W=2 level of kernel compiler warnings warns about the use of
uninitialised variables in a few locations. While these uninitialised
variables were not used in reality, this still produced compiler warnings.

Address this by assigning the variables to NULL and checking for NULL in
places it is not expected, returning -EIO in that case. This provides
at least some sanity checking at runtime as the compiler appears unable to
do that at compile time.
Reported-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/i2c/ccs/ccs-data.c

@@ -214,7 +214,7 @@ static int ccs_data_parse_regs(struct bin_container *bin,
 			       size_t *__num_regs, const void *payload,
 			       const void *endp, struct device *dev)
 {
-	struct ccs_reg *regs_base, *regs;
+	struct ccs_reg *regs_base = NULL, *regs = NULL;
 	size_t num_regs = 0;
 	u16 addr = 0;
 
@@ -285,6 +285,9 @@ static int ccs_data_parse_regs(struct bin_container *bin,
 		if (!bin->base) {
 			bin_reserve(bin, len);
 		} else if (__regs) {
+			if (!regs)
+				return -EIO;
+
 			regs->addr = addr;
 			regs->len = len;
 			regs->value = bin_alloc(bin, len);
@@ -305,8 +308,12 @@ static int ccs_data_parse_regs(struct bin_container *bin,
 	if (__num_regs)
 		*__num_regs = num_regs;
 
-	if (bin->base && __regs)
+	if (bin->base && __regs) {
+		if (!regs_base)
+			return -EIO;
+
 		*__regs = regs_base;
+	}
 
 	return 0;
 }
@@ -425,7 +432,7 @@ static int ccs_data_parse_rules(struct bin_container *bin,
 				size_t *__num_rules, const void *payload,
 				const void *endp, struct device *dev)
 {
-	struct ccs_rule *rules_base, *rules = NULL, *next_rule;
+	struct ccs_rule *rules_base = NULL, *rules = NULL, *next_rule = NULL;
 	size_t num_rules = 0;
 	const void *__next_rule = payload;
 	int rval;
@@ -483,6 +490,9 @@ static int ccs_data_parse_rules(struct bin_container *bin,
 			} else {
 				unsigned int i;
 
+				if (!next_rule)
+					return -EIO;
+
 				rules = next_rule;
 				next_rule++;
 
@@ -555,6 +565,9 @@ static int ccs_data_parse_rules(struct bin_container *bin,
 		bin_reserve(bin, sizeof(*rules) * num_rules);
 		*__num_rules = num_rules;
 	} else {
+		if (!rules_base)
+			return -EIO;
+
 		*__rules = rules_base;
 	}
 
@@ -690,7 +703,7 @@ static int ccs_data_parse_pdaf(struct bin_container *bin, struct ccs_pdaf_pix_lo
 	}
 
 	for (i = 0; i < max_block_type_id; i++) {
-		struct ccs_pdaf_pix_loc_pixel_desc_group *pdgroup;
+		struct ccs_pdaf_pix_loc_pixel_desc_group *pdgroup = NULL;
 		unsigned int j;
 
 		if (!is_contained(__num_pixel_descs, endp))
@@ -721,6 +734,9 @@ static int ccs_data_parse_pdaf(struct bin_container *bin, struct ccs_pdaf_pix_lo
 			if (!bin->base)
 				continue;
 
+			if (!pdgroup)
+				return -EIO;
+
 			pdesc = &pdgroup->descs[j];
 			pdesc->pixel_type = __pixel_desc->pixel_type;
 			pdesc->small_offset_x = __pixel_desc->small_offset_x;