The put_user(val,ptr) macro wants a pointer in the second parameter, but in
fat_ioctl_filldir() the d_name field references a whole "array of chars".
Usually the compiler automatically converts it and uses a pointer to that
array, but it's more clean to explicitly give the real pointer to where someting
is put, which is in this case the first character of the d_name[] array.
I noticed that issue while trying to optimize the parisc put_user() macro
and used an intermediate variable to store the pointer. In that case I
got this error:
In file included from include/linux/uaccess.h:11,
from include/linux/compat.h:17,
from fs/fat/dir.c:18:
fs/fat/dir.c: In function ‘fat_ioctl_filldir’:
fs/fat/dir.c:725:33: error: invalid initializer
725 | if (put_user(0, d2->d_name) || \
| ^~
include/asm/uaccess.h:152:33: note: in definition of macro ‘__put_user’
152 | __typeof__(ptr) __ptr = ptr; \
| ^~~
fs/fat/dir.c:759:1: note: in expansion of macro ‘FAT_IOCTL_FILLDIR_FUNC’
759 | FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
The patch below cleans it up.
Signed-off-by: Helge Deller <deller@xxxxxx>
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index c4a274285858..249825017da7 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -722,7 +722,7 @@ static int func(struct dir_context *ctx, const char *name, int name_len, \
if (name_len >= sizeof(d1->d_name)) \
name_len = sizeof(d1->d_name) - 1; \
\
- if (put_user(0, d2->d_name) || \
+ if (put_user(0, &d2->d_name[0]) || \
put_user(0, &d2->d_reclen) || \
copy_to_user(d1->d_name, name, name_len) || \
put_user(0, d1->d_name + name_len) || \
