[PATCH v2 1/1] cleanup: Fix sparse complaining about passing iomem ptr to no_free_ptr()

[PATCH v2 1/1] cleanup: Fix sparse complaining about passing iomem ptr to no_free_ptr()

[Ilpo Järvinen]

Calling no_free_ptr() for an __iomem pointer results in sparse
complaining about the types:
  warning: incorrect type in argument 1 (different address spaces)
     expected void const volatile *val
     got void [noderef] __iomem *__val
(The example from drivers/platform/x86/intel/pmc/core_ssram.c:283).

The problem is caused by the signature of __must_check_fn() added in
the commit 85be6d842447 ("cleanup: Make no_free_ptr() __must_check") to
enforce return value is always used.

Use __force to allow both iomem and non-iomem pointers to be given for
no_free_ptr().

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202403050547.qnZtuNlN-lkp@intel.com/
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---

I've no strong preferences through which tree this patch is routed.

v2:
- Rebased & updated line number to match the current code.

 include/linux/cleanup.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h
index ec00e3f7af2b..ee2614adb785 100644
--- a/include/linux/cleanup.h
+++ b/include/linux/cleanup.h
@@ -212,7 +212,7 @@ const volatile void * __must_check_fn(const volatile void *val)
 { return val; }
 
 #define no_free_ptr(p) \
-	((typeof(p)) __must_check_fn(__get_and_null(p, NULL)))
+	((typeof(p)) __must_check_fn((__force const volatile void *)__get_and_null(p, NULL)))
 
 #define return_ptr(p)	return no_free_ptr(p)
 

base-commit: 80e54e84911a923c40d7bee33a34c1b4be148d7a
-- 
2.39.5

[tip: core/urgent] <linux/cleanup.h>: Allow the passing of both iomem and non-iomem pointers to no_free_ptr()

[tip-bot2 for Ilpo Järvinen]

The following commit has been merged into the core/urgent branch of tip:

Commit-ID:     366fef794bd2b7c2e9df933f6828dd9739bfba84
Gitweb:        https://git.kernel.org/tip/366fef794bd2b7c2e9df933f6828dd9739bfba84
Author:        Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
AuthorDate:    Mon, 10 Mar 2025 14:21:58 +02:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Mon, 10 Mar 2025 20:02:14 +01:00

<linux/cleanup.h>: Allow the passing of both iomem and non-iomem pointers to no_free_ptr()

Calling no_free_ptr() for an __iomem pointer results in Sparse
complaining about the types:

  warning: incorrect type in argument 1 (different address spaces)
     expected void const volatile *val
     got void [noderef] __iomem *__val

[ The example is from drivers/platform/x86/intel/pmc/core_ssram.c:283 ]

The problem is caused by the signature of __must_check_fn() added in:

  85be6d842447 ("cleanup: Make no_free_ptr() __must_check")

... to enforce that the return value is always used.

Use __force to allow both iomem and non-iomem pointers to be given for
no_free_ptr().

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250310122158.20966-1-ilpo.jarvinen@linux.intel.com
Closes: https://lore.kernel.org/oe-kbuild-all/202403050547.qnZtuNlN-lkp@intel.com/
---
 include/linux/cleanup.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h
index ec00e3f..ee2614a 100644
--- a/include/linux/cleanup.h
+++ b/include/linux/cleanup.h
@@ -212,7 +212,7 @@ const volatile void * __must_check_fn(const volatile void *val)
 { return val; }
 
 #define no_free_ptr(p) \
-	((typeof(p)) __must_check_fn(__get_and_null(p, NULL)))
+	((typeof(p)) __must_check_fn((__force const volatile void *)__get_and_null(p, NULL)))
 
 #define return_ptr(p)	return no_free_ptr(p)