Merge remote-tracking branch 'origin/upstream-f2fs-stable-linux-4.4.y' into android-4.4

6944da0a68ca treewide: Use array_size in f2fs_kvzalloc()
f15443db99c3 treewide: Use array_size() in f2fs_kzalloc()
3ea03ea4bd09 treewide: Use array_size() in f2fs_kmalloc()
c41203299a52 overflow.h: Add allocation size calculation helpers
d400752f547f f2fs: fix to clear FI_VOLATILE_FILE correctly
853e7339b634 f2fs: let sync node IO interrupt async one
6a4540cf1984 f2fs: don't change wbc->sync_mode
588ecdfd7d02 f2fs: fix to update mtime correctly
1ae5aadab191 fs: f2fs: insert space around that ':' and ', '
39ee53e22320 fs: f2fs: add missing blank lines after declarations
d5b4710fcf38 fs: f2fs: changed variable type of offset "unsigned" to "loff_t"
c35da89531b3 f2fs: clean up symbol namespace
fcf37e16f3cb f2fs: make set_de_type() static
5d1633aa1071 f2fs: make __f2fs_write_data_pages() static
cc8093af7c42 f2fs: fix to avoid accessing cross the boundary
b7f559467095 f2fs: fix to let caller retry allocating block address
e48fcd857657 disable loading f2fs module on PAGE_SIZE > 4KB
02afc275a5bd f2fs: fix error path of move_data_page
0291bd36d076 f2fs: don't drop dentry pages after fs shutdown
a1259450b6db f2fs: fix to avoid race during access gc_thread pointer
d2e0f2f786a6 f2fs: clean up with clear_radix_tree_dirty_tag
c74034518fdc f2fs: fix to don't trigger writeback during recovery
e72a2cca82d8 f2fs: clear discard_wake earlier
b25a1872e9a5 f2fs: let discard thread wait a little longer if dev is busy
b125dfb20d18 f2fs: avoid stucking GC due to atomic write
405909e7f532 f2fs: introduce sbi->gc_mode to determine the policy
1f62e4702a34 f2fs: keep migration IO order in LFS mode
c4408c238722 f2fs: fix to wait page writeback during revoking atomic write
9db5be4af890 f2fs: Fix deadlock in shutdown ioctl
ed74404955cd f2fs: detect synchronous writeback more earlier
91e7d9d2ddbf mm: remove nr_pages argument from pagevec_lookup_{,range}_tag()
feb94dc82928 ceph: use pagevec_lookup_range_nr_tag()
f3aa4a25b8b0 mm: add variant of pagevec_lookup_range_tag() taking number of pages
8914877e374a mm: use pagevec_lookup_range_tag() in write_cache_pages()
26778b87a006 mm: use pagevec_lookup_range_tag() in __filemap_fdatawait_range()
94f1b99298bd nilfs2: use pagevec_lookup_range_tag()
160355d69f46 gfs2: use pagevec_lookup_range_tag()
564108e83a74 f2fs: use find_get_pages_tag() for looking up single page
6cf6fb8645ff f2fs: simplify page iteration loops
a05d8a6a2bde f2fs: use pagevec_lookup_range_tag()
18a4848ffded ext4: use pagevec_lookup_range_tag()
1c7be24f65cd ceph: use pagevec_lookup_range_tag()
e25fadabb5c7 btrfs: use pagevec_lookup_range_tag()
bf9510b162c4 mm: implement find_get_pages_range_tag()
461247b21fde f2fs: clean up with is_valid_blkaddr()
a5d0ccbc189a f2fs: fix to initialize min_mtime with ULLONG_MAX
9bb4d22cf5de f2fs: fix to let checkpoint guarantee atomic page persistence
cdcf2b3e2559 f2fs: fix to initialize i_current_depth according to inode type
331ae0c25b44 Revert "f2fs: add ovp valid_blocks check for bg gc victim to fg_gc"
2494cc7c0bcd f2fs: don't drop any page on f2fs_cp_error() case
0037c639e63d f2fs: fix spelling mistake: "extenstion" -> "extension"
2bba5b8eb867 f2fs: enhance sanity_check_raw_super() to avoid potential overflows
9bb86b63dc0f f2fs: treat volatile file's data as hot one
2cf64590361e f2fs: introduce release_discard_addr() for cleanup
03279ce90b46 f2fs: fix potential overflow
f46eddc4da48 f2fs: rename dio_rwsem to i_gc_rwsem
bb015824532c f2fs: move mnt_want_write_file after range check
8bb9a8da75d1 f2fs: fix missing clear FI_NO_PREALLOC in some error case
cb38cc4e1d02 f2fs: enforce fsync_mode=strict for renamed directory
26bf4e8a96aa f2fs: sanity check for total valid node blocks
78f8b0f46fa2 f2fs: sanity check on sit entry
ab758ada220f f2fs: avoid bug_on on corrupted inode
1a5d1966c0ca f2fs: give message and set need_fsck given broken node id
b025f6dfc018 f2fs: clean up commit_inmem_pages()
7aff5c69da4c f2fs: do not check F2FS_INLINE_DOTS in recover
23d00b02878e f2fs: remove duplicated dquot_initialize and fix error handling
937f4ef79e25 f2fs: stop issue discard if something wrong with f2fs
a6d74bb282ad f2fs: fix return value in f2fs_ioc_commit_atomic_write
258489ec5220 f2fs: allocate hot_data for atomic write more strictly
aa857e0f3b09 f2fs: check if inmem_pages list is empty correctly
9d77ded0a71d f2fs: fix race in between GC and atomic open
0d17eb90b56a f2fs: change le32 to le16 of f2fs_inode->i_extra_size
ea2813111f1f f2fs: check cur_valid_map_mir & raw_sit block count when flush sit entries
9190cadf38db f2fs: correct return value of f2fs_trim_fs
17f85d070886 f2fs: fix to show missing bits in FS_IOC_GETFLAGS
3e90db63fcfc f2fs: remove unneeded F2FS_PROJINHERIT_FL
298032d4d4a6 f2fs: don't use GFP_ZERO for page caches
fdf61219dc25 f2fs: issue all big range discards in umount process
cd79eb2b5e45 f2fs: remove redundant block plug
ec034d0f14ca f2fs: remove unmatched zero_user_segment when convert inline dentry
71aaced0e1ee f2fs: introduce private inode status mapping
e7724207f71e fscrypt: log the crypto algorithm implementations
4cbda579cd3d crypto: api - Add crypto_type_has_alg helper
b24dcaae8753 crypto: skcipher - Add low-level skcipher interface
a9146e423547 crypto: skcipher - Add helper to retrieve driver name
a0ca4bdf4744 crypto: skcipher - Add default key size helper
eb13e0b69296 fscrypt: add Speck128/256 support
27a0e77380a3 fscrypt: only derive the needed portion of the key
f68a71fa8f77 fscrypt: separate key lookup from key derivation
52359cf4fd6d fscrypt: use a common logging function
ff8e7c745e2b fscrypt: remove internal key size constants
7149dd4d39b5 fscrypt: remove unnecessary check for non-logon key type
56446c91422e fscrypt: make fscrypt_operations.max_namelen an integer
f572a22ef9a5 fscrypt: drop empty name check from fname_decrypt()
0077eff1d2e3 fscrypt: drop max_namelen check from fname_decrypt()
3f7af9d27fd6 fscrypt: don't special-case EOPNOTSUPP from fscrypt_get_encryption_info()
52c51f7b7bde fscrypt: don't clear flags on crypto transform
89b7fb82982f fscrypt: remove stale comment from fscrypt_d_revalidate()
d56de4e926ad fscrypt: remove error messages for skcipher_request_alloc() failure
f68d3b84aef1 fscrypt: remove unnecessary NULL check when allocating skcipher
fb10231825e9 fscrypt: clean up after fscrypt_prepare_lookup() conversions
39b144490606 fscrypt: use unbound workqueue for decryption

Change-Id: Ied79ecd97385c05ef26e6b7b24d250eee9ec4e47
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>

1 files changed, 278 insertions, 0 deletions

diff --git a/include/linux/overflow.h b/include/linux/overflow.h
new file mode 100644
index 000000000000..8712ff70995f
--- /dev/null
+++ b/include/linux/overflow.h
@@ -0,0 +1,278 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+#ifndef __LINUX_OVERFLOW_H
+#define __LINUX_OVERFLOW_H
+
+#include <linux/compiler.h>
+
+/*
+ * In the fallback code below, we need to compute the minimum and
+ * maximum values representable in a given type. These macros may also
+ * be useful elsewhere, so we provide them outside the
+ * COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW block.
+ *
+ * It would seem more obvious to do something like
+ *
+ * #define type_min(T) (T)(is_signed_type(T) ? (T)1 << (8*sizeof(T)-1) : 0)
+ * #define type_max(T) (T)(is_signed_type(T) ? ((T)1 << (8*sizeof(T)-1)) - 1 : ~(T)0)
+ *
+ * Unfortunately, the middle expressions, strictly speaking, have
+ * undefined behaviour, and at least some versions of gcc warn about
+ * the type_max expression (but not if -fsanitize=undefined is in
+ * effect; in that case, the warning is deferred to runtime...).
+ *
+ * The slightly excessive casting in type_min is to make sure the
+ * macros also produce sensible values for the exotic type _Bool. [The
+ * overflow checkers only almost work for _Bool, but that's
+ * a-feature-not-a-bug, since people shouldn't be doing arithmetic on
+ * _Bools. Besides, the gcc builtins don't allow _Bool* as third
+ * argument.]
+ *
+ * Idea stolen from
+ * https://mail-index.netbsd.org/tech-misc/2007/02/05/0000.html -
+ * credit to Christian Biere.
+ */
+#define is_signed_type(type)       (((type)(-1)) < (type)1)
+#define __type_half_max(type) ((type)1 << (8*sizeof(type) - 1 - is_signed_type(type)))
+#define type_max(T) ((T)((__type_half_max(T) - 1) + __type_half_max(T)))
+#define type_min(T) ((T)((T)-type_max(T)-(T)1))
+
+
+#ifdef COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW
+/*
+ * For simplicity and code hygiene, the fallback code below insists on
+ * a, b and *d having the same type (similar to the min() and max()
+ * macros), whereas gcc's type-generic overflow checkers accept
+ * different types. Hence we don't just make check_add_overflow an
+ * alias for __builtin_add_overflow, but add type checks similar to
+ * below.
+ */
+#define check_add_overflow(a, b, d) ({		\
+	typeof(a) __a = (a);			\
+	typeof(b) __b = (b);			\
+	typeof(d) __d = (d);			\
+	(void) (&__a == &__b);			\
+	(void) (&__a == __d);			\
+	__builtin_add_overflow(__a, __b, __d);	\
+})
+
+#define check_sub_overflow(a, b, d) ({		\
+	typeof(a) __a = (a);			\
+	typeof(b) __b = (b);			\
+	typeof(d) __d = (d);			\
+	(void) (&__a == &__b);			\
+	(void) (&__a == __d);			\
+	__builtin_sub_overflow(__a, __b, __d);	\
+})
+
+#define check_mul_overflow(a, b, d) ({		\
+	typeof(a) __a = (a);			\
+	typeof(b) __b = (b);			\
+	typeof(d) __d = (d);			\
+	(void) (&__a == &__b);			\
+	(void) (&__a == __d);			\
+	__builtin_mul_overflow(__a, __b, __d);	\
+})
+
+#else
+
+
+/* Checking for unsigned overflow is relatively easy without causing UB. */
+#define __unsigned_add_overflow(a, b, d) ({	\
+	typeof(a) __a = (a);			\
+	typeof(b) __b = (b);			\
+	typeof(d) __d = (d);			\
+	(void) (&__a == &__b);			\
+	(void) (&__a == __d);			\
+	*__d = __a + __b;			\
+	*__d < __a;				\
+})
+#define __unsigned_sub_overflow(a, b, d) ({	\
+	typeof(a) __a = (a);			\
+	typeof(b) __b = (b);			\
+	typeof(d) __d = (d);			\
+	(void) (&__a == &__b);			\
+	(void) (&__a == __d);			\
+	*__d = __a - __b;			\
+	__a < __b;				\
+})
+/*
+ * If one of a or b is a compile-time constant, this avoids a division.
+ */
+#define __unsigned_mul_overflow(a, b, d) ({		\
+	typeof(a) __a = (a);				\
+	typeof(b) __b = (b);				\
+	typeof(d) __d = (d);				\
+	(void) (&__a == &__b);				\
+	(void) (&__a == __d);				\
+	*__d = __a * __b;				\
+	__builtin_constant_p(__b) ?			\
+	  __b > 0 && __a > type_max(typeof(__a)) / __b : \
+	  __a > 0 && __b > type_max(typeof(__b)) / __a;	 \
+})
+
+/*
+ * For signed types, detecting overflow is much harder, especially if
+ * we want to avoid UB. But the interface of these macros is such that
+ * we must provide a result in *d, and in fact we must produce the
+ * result promised by gcc's builtins, which is simply the possibly
+ * wrapped-around value. Fortunately, we can just formally do the
+ * operations in the widest relevant unsigned type (u64) and then
+ * truncate the result - gcc is smart enough to generate the same code
+ * with and without the (u64) casts.
+ */
+
+/*
+ * Adding two signed integers can overflow only if they have the same
+ * sign, and overflow has happened iff the result has the opposite
+ * sign.
+ */
+#define __signed_add_overflow(a, b, d) ({	\
+	typeof(a) __a = (a);			\
+	typeof(b) __b = (b);			\
+	typeof(d) __d = (d);			\
+	(void) (&__a == &__b);			\
+	(void) (&__a == __d);			\
+	*__d = (u64)__a + (u64)__b;		\
+	(((~(__a ^ __b)) & (*__d ^ __a))	\
+		& type_min(typeof(__a))) != 0;	\
+})
+
+/*
+ * Subtraction is similar, except that overflow can now happen only
+ * when the signs are opposite. In this case, overflow has happened if
+ * the result has the opposite sign of a.
+ */
+#define __signed_sub_overflow(a, b, d) ({	\
+	typeof(a) __a = (a);			\
+	typeof(b) __b = (b);			\
+	typeof(d) __d = (d);			\
+	(void) (&__a == &__b);			\
+	(void) (&__a == __d);			\
+	*__d = (u64)__a - (u64)__b;		\
+	((((__a ^ __b)) & (*__d ^ __a))		\
+		& type_min(typeof(__a))) != 0;	\
+})
+
+/*
+ * Signed multiplication is rather hard. gcc always follows C99, so
+ * division is truncated towards 0. This means that we can write the
+ * overflow check like this:
+ *
+ * (a > 0 && (b > MAX/a || b < MIN/a)) ||
+ * (a < -1 && (b > MIN/a || b < MAX/a) ||
+ * (a == -1 && b == MIN)
+ *
+ * The redundant casts of -1 are to silence an annoying -Wtype-limits
+ * (included in -Wextra) warning: When the type is u8 or u16, the
+ * __b_c_e in check_mul_overflow obviously selects
+ * __unsigned_mul_overflow, but unfortunately gcc still parses this
+ * code and warns about the limited range of __b.
+ */
+
+#define __signed_mul_overflow(a, b, d) ({				\
+	typeof(a) __a = (a);						\
+	typeof(b) __b = (b);						\
+	typeof(d) __d = (d);						\
+	typeof(a) __tmax = type_max(typeof(a));				\
+	typeof(a) __tmin = type_min(typeof(a));				\
+	(void) (&__a == &__b);						\
+	(void) (&__a == __d);						\
+	*__d = (u64)__a * (u64)__b;					\
+	(__b > 0   && (__a > __tmax/__b || __a < __tmin/__b)) ||	\
+	(__b < (typeof(__b))-1  && (__a > __tmin/__b || __a < __tmax/__b)) || \
+	(__b == (typeof(__b))-1 && __a == __tmin);			\
+})
+
+
+#define check_add_overflow(a, b, d)					\
+	__builtin_choose_expr(is_signed_type(typeof(a)),		\
+			__signed_add_overflow(a, b, d),			\
+			__unsigned_add_overflow(a, b, d))
+
+#define check_sub_overflow(a, b, d)					\
+	__builtin_choose_expr(is_signed_type(typeof(a)),		\
+			__signed_sub_overflow(a, b, d),			\
+			__unsigned_sub_overflow(a, b, d))
+
+#define check_mul_overflow(a, b, d)					\
+	__builtin_choose_expr(is_signed_type(typeof(a)),		\
+			__signed_mul_overflow(a, b, d),			\
+			__unsigned_mul_overflow(a, b, d))
+
+
+#endif /* COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW */
+
+/**
+ * array_size() - Calculate size of 2-dimensional array.
+ *
+ * @a: dimension one
+ * @b: dimension two
+ *
+ * Calculates size of 2-dimensional array: @a * @b.
+ *
+ * Returns: number of bytes needed to represent the array or SIZE_MAX on
+ * overflow.
+ */
+static inline __must_check size_t array_size(size_t a, size_t b)
+{
+	size_t bytes;
+
+	if (check_mul_overflow(a, b, &bytes))
+		return SIZE_MAX;
+
+	return bytes;
+}
+
+/**
+ * array3_size() - Calculate size of 3-dimensional array.
+ *
+ * @a: dimension one
+ * @b: dimension two
+ * @c: dimension three
+ *
+ * Calculates size of 3-dimensional array: @a * @b * @c.
+ *
+ * Returns: number of bytes needed to represent the array or SIZE_MAX on
+ * overflow.
+ */
+static inline __must_check size_t array3_size(size_t a, size_t b, size_t c)
+{
+	size_t bytes;
+
+	if (check_mul_overflow(a, b, &bytes))
+		return SIZE_MAX;
+	if (check_mul_overflow(bytes, c, &bytes))
+		return SIZE_MAX;
+
+	return bytes;
+}
+
+static inline __must_check size_t __ab_c_size(size_t n, size_t size, size_t c)
+{
+	size_t bytes;
+
+	if (check_mul_overflow(n, size, &bytes))
+		return SIZE_MAX;
+	if (check_add_overflow(bytes, c, &bytes))
+		return SIZE_MAX;
+
+	return bytes;
+}
+
+/**
+ * struct_size() - Calculate size of structure with trailing array.
+ * @p: Pointer to the structure.
+ * @member: Name of the array member.
+ * @n: Number of elements in the array.
+ *
+ * Calculates size of memory needed for structure @p followed by an
+ * array of @n @member elements.
+ *
+ * Return: number of bytes needed or SIZE_MAX on overflow.
+ */
+#define struct_size(p, member, n)					\
+	__ab_c_size(n,							\
+		    sizeof(*(p)->member) + __must_be_array((p)->member),\
+		    sizeof(*(p)))
+
+#endif /* __LINUX_OVERFLOW_H */