[PATCH] staging: vchiq_arm: Make vchiq_platform_init() static

[Arnd Bergmann]

On Wed, Apr 19, 2023, at 23:21, Nick Desaulniers wrote:
> On Wed, Apr 19, 2023 at 1:51 AM Simon Horman <horms at kernel.org> wrote:

> Marking something as `depends on OF_DYNAMIC`. (Not sure whether Arnd
> meant that for BCM2835_VCHIQ or BCM_VIDEOCORE).
> Perhaps try that?
>
>>
>> I'm a bit surprised as I didn't observe such a thing.
>> But I also don't dispute it - clearly my testing was inadequate.
>>
>> I'll try and dig a bit deeper into this one.
>> Perhaps starting with the report from the kernel test robot [3]

I have this in my randconfig build tree, but it looks like I never
sent it out.

----
>From bb01f96d7dd66fc437302785f623a3ab323d486e Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd at arndb.de>
Date: Mon, 20 Mar 2023 11:33:52 +0100
Subject: [PATCH] staging: vchiq_arm: mark vchiq_platform_init() static

This function has no callers from other files, and the declaration
was removed a while ago, causing a W=1 warning:

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:465:5: error: no previous prototype for 'vchiq_platform_init'

Marking it static solves this problem but introduces a new warning
since gcc determines that 'g_fragments_base' is never initialized
in some kernel configurations:

In file included from include/linux/string.h:254,
                 from include/linux/bitmap.h:11,
                 from include/linux/cpumask.h:12,
                 from include/linux/mm_types_task.h:14,
                 from include/linux/mm_types.h:5,
                 from include/linux/buildid.h:5,
                 from include/linux/module.h:14,
                 from drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:8:
In function 'memcpy_to_page',
    inlined from 'free_pagelist' at drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:433:4:
include/linux/fortify-string.h:57:33: error: argument 2 null where non-null expected [-Werror=nonnull]
include/linux/highmem.h:427:9: note: in expansion of macro 'memcpy'
  427 |         memcpy(to + offset, from, len);
      |         ^~~~~~

Add a NULL pointer check for this in addition to the static annotation
to avoid both.

Fixes: 89cc4218f640 ("staging: vchiq_arm: drop unnecessary declarations")
Signed-off-by: Arnd Bergmann <arnd at arndb.de>

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index 90a3958d1f29..aa2313f3bcab 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -415,7 +415,7 @@ free_pagelist(struct vchiq_instance *instance, struct vchiq_pagelist_info *pagel
 	pagelistinfo->scatterlist_mapped = 0;
 
 	/* Deal with any partial cache lines (fragments) */
-	if (pagelist->type >= PAGELIST_READ_WITH_FRAGMENTS) {
+	if (pagelist->type >= PAGELIST_READ_WITH_FRAGMENTS && g_fragments_base) {
 		char *fragments = g_fragments_base +
 			(pagelist->type - PAGELIST_READ_WITH_FRAGMENTS) *
 			g_fragments_size;
@@ -462,7 +462,7 @@ free_pagelist(struct vchiq_instance *instance, struct vchiq_pagelist_info *pagel
 	cleanup_pagelistinfo(instance, pagelistinfo);
 }
 
-int vchiq_platform_init(struct platform_device *pdev, struct vchiq_state *state)
+static int vchiq_platform_init(struct platform_device *pdev, struct vchiq_state *state)
 {
 	struct device *dev = &pdev->dev;
 	struct vchiq_drvdata *drvdata = platform_get_drvdata(pdev);