Sparse will try to check casting of simple integer types which are marked as __bitwise. This for example "disallows" simple casting of __be{16,32,64} or __le{16,32,64} to other types. This is also true for pointers to variables with this type.
But the new generic {get,put}_unaligned is doing that by (reinterpret) casting the original pointer to a new (anonymous) struct pointer. This will then create warnings like:
net/batman-adv/distributed-arp-table.c:1461:19: warning: cast from restricted __be32 * net/batman-adv/distributed-arp-table.c:1510:23: warning: cast from restricted __be32 [usertype] *[assigned] magic net/batman-adv/distributed-arp-table.c:1588:24: warning: cast from restricted __be32 [usertype] *[assigned] yiaddr
The special attribute force must be used in such statements when the cast is known to be safe to avoid these warnings.
Fixes: 803f4e1eab7a ("asm-generic: simplify asm/unaligned.h") Signed-off-by: Sven Eckelmann sven@narfation.org --- include/asm-generic/unaligned.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/unaligned.h b/include/asm-generic/unaligned.h index 1c4242416c9f..e2b23e5bf945 100644 --- a/include/asm-generic/unaligned.h +++ b/include/asm-generic/unaligned.h @@ -10,12 +10,13 @@ #include <asm/byteorder.h>
#define __get_unaligned_t(type, ptr) ({ \ - const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \ + const struct { type x; } __packed *__pptr; \ + __pptr = (__force typeof(__pptr))(ptr); \ __pptr->x; \ })
#define __put_unaligned_t(type, val, ptr) do { \ - struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \ + struct { type x; } __packed *__pptr = (__force typeof(__pptr))(ptr); \ __pptr->x = (val); \ } while (0)