diff mbox series

[06/10] mfd: ab3100-core: Fix incompatible types in comparison expression warning

Message ID 20200624150704.2729736-7-lee.jones@linaro.org (mailing list archive)
State New, archived
Headers show
Series Fix a bunch of W=1 warnings in MFD | expand

Commit Message

Lee Jones June 24, 2020, 3:07 p.m. UTC
Smatch reports:

 drivers/mfd/ab3100-core.c:501:20: error: incompatible types in comparison expression (different type sizes):
 drivers/mfd/ab3100-core.c:501:20:    unsigned int *
 drivers/mfd/ab3100-core.c:501:20:    unsigned long *
 drivers/mfd/ab8500-debugfs.c:1804:20: error: incompatible types in comparison expression (different type sizes):
 drivers/mfd/ab8500-debugfs.c:1804:20:    unsigned int *
 drivers/mfd/ab8500-debugfs.c:1804:20:    unsigned long *

Since the second min() argument can be less than 0 a signed
variable is required for assignment.  However, the non-sized
type size_t is passed in from the userspace handlers.  In order
to firstly compare, then assign the smallest value, we firstly
need to cast them both to the same as the receiving size_t typed
variable.

Cc: <stable@vger.kernel.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/mfd/ab3100-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Linus Walleij July 7, 2020, 12:33 p.m. UTC | #1
On Wed, Jun 24, 2020 at 5:07 PM Lee Jones <lee.jones@linaro.org> wrote:

> Smatch reports:
>
>  drivers/mfd/ab3100-core.c:501:20: error: incompatible types in comparison expression (different type sizes):
>  drivers/mfd/ab3100-core.c:501:20:    unsigned int *
>  drivers/mfd/ab3100-core.c:501:20:    unsigned long *
>  drivers/mfd/ab8500-debugfs.c:1804:20: error: incompatible types in comparison expression (different type sizes):
>  drivers/mfd/ab8500-debugfs.c:1804:20:    unsigned int *
>  drivers/mfd/ab8500-debugfs.c:1804:20:    unsigned long *
>
> Since the second min() argument can be less than 0 a signed
> variable is required for assignment.  However, the non-sized
> type size_t is passed in from the userspace handlers.  In order
> to firstly compare, then assign the smallest value, we firstly
> need to cast them both to the same as the receiving size_t typed
> variable.
>
> Cc: <stable@vger.kernel.org>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Lee Jones <lee.jones@linaro.org>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij
diff mbox series

Patch

diff --git a/drivers/mfd/ab3100-core.c b/drivers/mfd/ab3100-core.c
index 57723f116bb58..ee71ae04b5e63 100644
--- a/drivers/mfd/ab3100-core.c
+++ b/drivers/mfd/ab3100-core.c
@@ -498,7 +498,7 @@  static ssize_t ab3100_get_set_reg(struct file *file,
 	int i = 0;
 
 	/* Get userspace string and assure termination */
-	buf_size = min(count, (sizeof(buf)-1));
+	buf_size = min((ssize_t)count, (ssize_t)(sizeof(buf)-1));
 	if (copy_from_user(buf, user_buf, buf_size))
 		return -EFAULT;
 	buf[buf_size] = 0;