[PATCH] vmci_host: print unexpanded names of ioctl requests in debug messages

From: Gleb Fotengauer-Malinovskiy
Date: Tue Mar 02 2021 - 13:47:01 EST


__stringify macro function expands its arguments, but in this messages
we expect to see ioctl request name instead of it's _IOC macro
expansion.

$ cat stringify.c

#include <stdio.h>
#include <asm/ioctl.h>

#define __stringify_1(x) #x
#define __stringify(x) __stringify_1(x)

#define VMCI_DO_IOCTL(ioctl_name) \
char *name = __stringify(IOCTL_VMCI_ ## ioctl_name);

int main() {
VMCI_DO_IOCTL(INIT_CONTEXT)
printf("%s\n", name);
}
$ cc stringify.c
$ ./a.out
(((0U) << (((0+8)+8)+14)) | (((7)) << (0+8)) | (((0xa0)) << 0) | ((0) << ((0+8)+8)))

Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@xxxxxxxxxxxx>
---
drivers/misc/vmw_vmci/vmci_host.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/vmw_vmci/vmci_host.c b/drivers/misc/vmw_vmci/vmci_host.c
index 2d8328d928d5..da1e2a773823 100644
--- a/drivers/misc/vmw_vmci/vmci_host.c
+++ b/drivers/misc/vmw_vmci/vmci_host.c
@@ -908,7 +908,7 @@ static long vmci_host_unlocked_ioctl(struct file *filp,
unsigned int iocmd, unsigned long ioarg)
{
#define VMCI_DO_IOCTL(ioctl_name, ioctl_fn) do { \
- char *name = __stringify(IOCTL_VMCI_ ## ioctl_name); \
+ char *name = "IOCTL_VMCI_" # ioctl_name; \
return vmci_host_do_ ## ioctl_fn( \
vmci_host_dev, name, uptr); \
} while (0)
--
glebfm