When building bcachefs for 32-bit ARM, there is a warning when using
min() to compare a variable of type 'size_t' with an expression of type
'unsigned long':
fs/bcachefs/checksum.c:142:22: error: comparison of distinct pointer types
('typeof (len) *' (aka 'unsigned int *') and 'typeof (((1UL) << 12) - offset)
*' (aka 'unsigned long *')) [-Werror,-Wcompare-distinct-pointer-types]
142 | unsigned pg_len = min(len, PAGE_SIZE -
offset);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/minmax.h:69:19: note: expanded from macro 'min'
69 | #define min(x, y) __careful_cmp(x, y, <)
| ^~~~~~~~~~~~~~~~~~~~~~
include/linux/minmax.h:38:24: note: expanded from macro '__careful_cmp'
38 | __builtin_choose_expr(__safe_cmp(x, y), \
| ^~~~~~~~~~~~~~~~
include/linux/minmax.h:28:4: note: expanded from macro '__safe_cmp'
28 | (__typecheck(x, y) && __no_side_effects(x, y))
| ^~~~~~~~~~~~~~~~~
include/linux/minmax.h:22:28: note: expanded from macro '__typecheck'
22 | (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
| ~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
1 error generated.
On 64-bit architectures, size_t is 'unsigned long', so there is no
warning when comparing these two expressions. Use min_t(size_t, ...) for
this situation, eliminating the warning.
Fixes: 1fb50457684f ("bcachefs: Fix memory corruption in encryption path")
Signed-off-by: Nathan Chancellor <[email protected]>
---
fs/bcachefs/checksum.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/bcachefs/checksum.c b/fs/bcachefs/checksum.c
index 36939020f67d..ff0c3cd39ee2 100644
--- a/fs/bcachefs/checksum.c
+++ b/fs/bcachefs/checksum.c
@@ -139,7 +139,7 @@ static inline int do_encrypt(struct crypto_sync_skcipher
*tfm,
for (i = 0; i < pages; i++) {
unsigned offset = offset_in_page(buf);
- unsigned pg_len = min(len, PAGE_SIZE - offset);
+ unsigned pg_len = min_t(size_t, len, PAGE_SIZE -
offset);
sg_set_page(sg + i, vmalloc_to_page(buf), pg_len,
offset);
buf += pg_len;
--
2.42.0
