v4.19.13 snapshot.
diff --git a/include/linux/ceph/decode.h b/include/linux/ceph/decode.h
new file mode 100644
index 0000000..a6c2a48
--- /dev/null
+++ b/include/linux/ceph/decode.h
@@ -0,0 +1,381 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __CEPH_DECODE_H
+#define __CEPH_DECODE_H
+
+#include <linux/err.h>
+#include <linux/bug.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <asm/unaligned.h>
+
+#include <linux/ceph/types.h>
+
+/*
+ * in all cases,
+ * void **p pointer to position pointer
+ * void *end pointer to end of buffer (last byte + 1)
+ */
+
+static inline u64 ceph_decode_64(void **p)
+{
+ u64 v = get_unaligned_le64(*p);
+ *p += sizeof(u64);
+ return v;
+}
+static inline u32 ceph_decode_32(void **p)
+{
+ u32 v = get_unaligned_le32(*p);
+ *p += sizeof(u32);
+ return v;
+}
+static inline u16 ceph_decode_16(void **p)
+{
+ u16 v = get_unaligned_le16(*p);
+ *p += sizeof(u16);
+ return v;
+}
+static inline u8 ceph_decode_8(void **p)
+{
+ u8 v = *(u8 *)*p;
+ (*p)++;
+ return v;
+}
+static inline void ceph_decode_copy(void **p, void *pv, size_t n)
+{
+ memcpy(pv, *p, n);
+ *p += n;
+}
+
+/*
+ * bounds check input.
+ */
+static inline bool ceph_has_room(void **p, void *end, size_t n)
+{
+ return end >= *p && n <= end - *p;
+}
+
+#define ceph_decode_need(p, end, n, bad) \
+ do { \
+ if (!likely(ceph_has_room(p, end, n))) \
+ goto bad; \
+ } while (0)
+
+#define ceph_decode_64_safe(p, end, v, bad) \
+ do { \
+ ceph_decode_need(p, end, sizeof(u64), bad); \
+ v = ceph_decode_64(p); \
+ } while (0)
+#define ceph_decode_32_safe(p, end, v, bad) \
+ do { \
+ ceph_decode_need(p, end, sizeof(u32), bad); \
+ v = ceph_decode_32(p); \
+ } while (0)
+#define ceph_decode_16_safe(p, end, v, bad) \
+ do { \
+ ceph_decode_need(p, end, sizeof(u16), bad); \
+ v = ceph_decode_16(p); \
+ } while (0)
+#define ceph_decode_8_safe(p, end, v, bad) \
+ do { \
+ ceph_decode_need(p, end, sizeof(u8), bad); \
+ v = ceph_decode_8(p); \
+ } while (0)
+
+#define ceph_decode_copy_safe(p, end, pv, n, bad) \
+ do { \
+ ceph_decode_need(p, end, n, bad); \
+ ceph_decode_copy(p, pv, n); \
+ } while (0)
+
+/*
+ * Allocate a buffer big enough to hold the wire-encoded string, and
+ * decode the string into it. The resulting string will always be
+ * terminated with '\0'. If successful, *p will be advanced
+ * past the decoded data. Also, if lenp is not a null pointer, the
+ * length (not including the terminating '\0') will be recorded in
+ * *lenp. Note that a zero-length string is a valid return value.
+ *
+ * Returns a pointer to the newly-allocated string buffer, or a
+ * pointer-coded errno if an error occurs. Neither *p nor *lenp
+ * will have been updated if an error is returned.
+ *
+ * There are two possible failures:
+ * - converting the string would require accessing memory at or
+ * beyond the "end" pointer provided (-ERANGE)
+ * - memory could not be allocated for the result (-ENOMEM)
+ */
+static inline char *ceph_extract_encoded_string(void **p, void *end,
+ size_t *lenp, gfp_t gfp)
+{
+ u32 len;
+ void *sp = *p;
+ char *buf;
+
+ ceph_decode_32_safe(&sp, end, len, bad);
+ if (!ceph_has_room(&sp, end, len))
+ goto bad;
+
+ buf = kmalloc(len + 1, gfp);
+ if (!buf)
+ return ERR_PTR(-ENOMEM);
+
+ if (len)
+ memcpy(buf, sp, len);
+ buf[len] = '\0';
+
+ *p = (char *) *p + sizeof (u32) + len;
+ if (lenp)
+ *lenp = (size_t) len;
+
+ return buf;
+
+bad:
+ return ERR_PTR(-ERANGE);
+}
+
+/*
+ * skip helpers
+ */
+#define ceph_decode_skip_n(p, end, n, bad) \
+ do { \
+ ceph_decode_need(p, end, n, bad); \
+ *p += n; \
+ } while (0)
+
+#define ceph_decode_skip_64(p, end, bad) \
+ceph_decode_skip_n(p, end, sizeof(u64), bad)
+
+#define ceph_decode_skip_32(p, end, bad) \
+ceph_decode_skip_n(p, end, sizeof(u32), bad)
+
+#define ceph_decode_skip_16(p, end, bad) \
+ceph_decode_skip_n(p, end, sizeof(u16), bad)
+
+#define ceph_decode_skip_8(p, end, bad) \
+ceph_decode_skip_n(p, end, sizeof(u8), bad)
+
+#define ceph_decode_skip_string(p, end, bad) \
+ do { \
+ u32 len; \
+ \
+ ceph_decode_32_safe(p, end, len, bad); \
+ ceph_decode_skip_n(p, end, len, bad); \
+ } while (0)
+
+#define ceph_decode_skip_set(p, end, type, bad) \
+ do { \
+ u32 len; \
+ \
+ ceph_decode_32_safe(p, end, len, bad); \
+ while (len--) \
+ ceph_decode_skip_##type(p, end, bad); \
+ } while (0)
+
+#define ceph_decode_skip_map(p, end, ktype, vtype, bad) \
+ do { \
+ u32 len; \
+ \
+ ceph_decode_32_safe(p, end, len, bad); \
+ while (len--) { \
+ ceph_decode_skip_##ktype(p, end, bad); \
+ ceph_decode_skip_##vtype(p, end, bad); \
+ } \
+ } while (0)
+
+#define ceph_decode_skip_map_of_map(p, end, ktype1, ktype2, vtype2, bad) \
+ do { \
+ u32 len; \
+ \
+ ceph_decode_32_safe(p, end, len, bad); \
+ while (len--) { \
+ ceph_decode_skip_##ktype1(p, end, bad); \
+ ceph_decode_skip_map(p, end, ktype2, vtype2, bad); \
+ } \
+ } while (0)
+
+/*
+ * struct ceph_timespec <-> struct timespec64
+ */
+static inline void ceph_decode_timespec64(struct timespec64 *ts,
+ const struct ceph_timespec *tv)
+{
+ /*
+ * This will still overflow in year 2106. We could extend
+ * the protocol to steal two more bits from tv_nsec to
+ * add three more 136 year epochs after that the way ext4
+ * does if necessary.
+ */
+ ts->tv_sec = (time64_t)le32_to_cpu(tv->tv_sec);
+ ts->tv_nsec = (long)le32_to_cpu(tv->tv_nsec);
+}
+static inline void ceph_encode_timespec64(struct ceph_timespec *tv,
+ const struct timespec64 *ts)
+{
+ tv->tv_sec = cpu_to_le32((u32)ts->tv_sec);
+ tv->tv_nsec = cpu_to_le32((u32)ts->tv_nsec);
+}
+
+/*
+ * sockaddr_storage <-> ceph_sockaddr
+ */
+static inline void ceph_encode_addr(struct ceph_entity_addr *a)
+{
+ __be16 ss_family = htons(a->in_addr.ss_family);
+ a->in_addr.ss_family = *(__u16 *)&ss_family;
+}
+static inline void ceph_decode_addr(struct ceph_entity_addr *a)
+{
+ __be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
+ a->in_addr.ss_family = ntohs(ss_family);
+ WARN_ON(a->in_addr.ss_family == 512);
+}
+
+/*
+ * encoders
+ */
+static inline void ceph_encode_64(void **p, u64 v)
+{
+ put_unaligned_le64(v, (__le64 *)*p);
+ *p += sizeof(u64);
+}
+static inline void ceph_encode_32(void **p, u32 v)
+{
+ put_unaligned_le32(v, (__le32 *)*p);
+ *p += sizeof(u32);
+}
+static inline void ceph_encode_16(void **p, u16 v)
+{
+ put_unaligned_le16(v, (__le16 *)*p);
+ *p += sizeof(u16);
+}
+static inline void ceph_encode_8(void **p, u8 v)
+{
+ *(u8 *)*p = v;
+ (*p)++;
+}
+static inline void ceph_encode_copy(void **p, const void *s, int len)
+{
+ memcpy(*p, s, len);
+ *p += len;
+}
+
+/*
+ * filepath, string encoders
+ */
+static inline void ceph_encode_filepath(void **p, void *end,
+ u64 ino, const char *path)
+{
+ u32 len = path ? strlen(path) : 0;
+ BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
+ ceph_encode_8(p, 1);
+ ceph_encode_64(p, ino);
+ ceph_encode_32(p, len);
+ if (len)
+ memcpy(*p, path, len);
+ *p += len;
+}
+
+static inline void ceph_encode_string(void **p, void *end,
+ const char *s, u32 len)
+{
+ BUG_ON(*p + sizeof(len) + len > end);
+ ceph_encode_32(p, len);
+ if (len)
+ memcpy(*p, s, len);
+ *p += len;
+}
+
+/*
+ * version and length starting block encoders/decoders
+ */
+
+/* current code version (u8) + compat code version (u8) + len of struct (u32) */
+#define CEPH_ENCODING_START_BLK_LEN 6
+
+/**
+ * ceph_start_encoding - start encoding block
+ * @struct_v: current (code) version of the encoding
+ * @struct_compat: oldest code version that can decode it
+ * @struct_len: length of struct encoding
+ */
+static inline void ceph_start_encoding(void **p, u8 struct_v, u8 struct_compat,
+ u32 struct_len)
+{
+ ceph_encode_8(p, struct_v);
+ ceph_encode_8(p, struct_compat);
+ ceph_encode_32(p, struct_len);
+}
+
+/**
+ * ceph_start_decoding - start decoding block
+ * @v: current version of the encoding that the code supports
+ * @name: name of the struct (free-form)
+ * @struct_v: out param for the encoding version
+ * @struct_len: out param for the length of struct encoding
+ *
+ * Validates the length of struct encoding, so unsafe ceph_decode_*
+ * variants can be used for decoding.
+ */
+static inline int ceph_start_decoding(void **p, void *end, u8 v,
+ const char *name, u8 *struct_v,
+ u32 *struct_len)
+{
+ u8 struct_compat;
+
+ ceph_decode_need(p, end, CEPH_ENCODING_START_BLK_LEN, bad);
+ *struct_v = ceph_decode_8(p);
+ struct_compat = ceph_decode_8(p);
+ if (v < struct_compat) {
+ pr_warn("got struct_v %d struct_compat %d > %d of %s\n",
+ *struct_v, struct_compat, v, name);
+ return -EINVAL;
+ }
+
+ *struct_len = ceph_decode_32(p);
+ ceph_decode_need(p, end, *struct_len, bad);
+ return 0;
+
+bad:
+ return -ERANGE;
+}
+
+#define ceph_encode_need(p, end, n, bad) \
+ do { \
+ if (!likely(ceph_has_room(p, end, n))) \
+ goto bad; \
+ } while (0)
+
+#define ceph_encode_64_safe(p, end, v, bad) \
+ do { \
+ ceph_encode_need(p, end, sizeof(u64), bad); \
+ ceph_encode_64(p, v); \
+ } while (0)
+#define ceph_encode_32_safe(p, end, v, bad) \
+ do { \
+ ceph_encode_need(p, end, sizeof(u32), bad); \
+ ceph_encode_32(p, v); \
+ } while (0)
+#define ceph_encode_16_safe(p, end, v, bad) \
+ do { \
+ ceph_encode_need(p, end, sizeof(u16), bad); \
+ ceph_encode_16(p, v); \
+ } while (0)
+#define ceph_encode_8_safe(p, end, v, bad) \
+ do { \
+ ceph_encode_need(p, end, sizeof(u8), bad); \
+ ceph_encode_8(p, v); \
+ } while (0)
+
+#define ceph_encode_copy_safe(p, end, pv, n, bad) \
+ do { \
+ ceph_encode_need(p, end, n, bad); \
+ ceph_encode_copy(p, pv, n); \
+ } while (0)
+#define ceph_encode_string_safe(p, end, s, n, bad) \
+ do { \
+ ceph_encode_need(p, end, n, bad); \
+ ceph_encode_string(p, end, s, n); \
+ } while (0)
+
+
+#endif