[PATCH] gpiolib: annotate struct acpi_gpio_mapping with __counted_by_ptr

[Bill Wendling <morbo@google.com>]

The 'data' pointer field in 'struct acpi_gpio_mapping' is associated
with the 'size' field, which represents the number of elements of
type 'struct acpi_gpio_params' allocated for 'data'.

To improve bounds checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE, annotate 'data' with the __counted_by_ptr
attribute.

Analysis of allocation, assignment, and access points shows that the
pointer is never accessed before the count is set, which guarantees that
this annotation is safe and will not cause runtime panics or
false-positive bounds checks.

Cc: codemender-patching+linux@google.com
Assisted-by: LLM
Signed-off-by: Bill Wendling <morbo@google.com>
---
 include/linux/gpio/consumer.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index fceeefd5f893..2b80cf7aa7e7 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -667,7 +667,7 @@ struct acpi_gpio_params {
 
 struct acpi_gpio_mapping {
 	const char *name;
-	const struct acpi_gpio_params *data;
+	const struct acpi_gpio_params *data __counted_by_ptr(size);
 	unsigned int size;
 
 /* Ignore IoRestriction field */
-- 
2.56.0.rc1.315.gc6ed9934b7-goog