Add a counterpart to IOV_PEEK_HEADER() that writes header data back
to an iov_tail after modification. If the header pointer matches the
original iov buffer location, it only advances the offset. Otherwise,
it copies the data using iov_from_buf().
Signed-off-by: Laurent Vivier
---
iov.c | 24 ++++++++++++++++++++++++
iov.h | 14 +++++++++++++-
2 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/iov.c b/iov.c
index cd48667226f3..296f24b61067 100644
--- a/iov.c
+++ b/iov.c
@@ -305,6 +305,30 @@ void *iov_peek_header_(struct iov_tail *tail, void *v, size_t len, size_t align)
return v;
}
+/**
+ * iov_put_header_() - Write header back to an IOV tail
+ * @tail: IOV tail to write header to
+ * @v: Pointer to header data to write
+ * @len: Length of header to write, in bytes
+ *
+ * Return: number of bytes written
+ */
+/* cppcheck-suppress unusedFunction */
+size_t iov_put_header_(struct iov_tail *tail, const void *v, size_t len)
+{
+ size_t l = len;
+
+ /* iov_peek_header_() already called iov_check_header() */
+ if ((char *)tail->iov[0].iov_base + tail->off != v)
+ l = iov_from_buf(tail->iov, tail->cnt, tail->off, v, len);
+
+ ASSERT(l == len);
+
+ tail->off += l;
+
+ return l;
+}
+
/**
* iov_remove_header_() - Remove a header from an IOV tail
* @tail: IOV tail to remove header from (modified)
diff --git a/iov.h b/iov.h
index d295d05b3bab..fe7c5163d2ab 100644
--- a/iov.h
+++ b/iov.h
@@ -90,6 +90,7 @@ bool iov_tail_prune(struct iov_tail *tail);
size_t iov_tail_size(struct iov_tail *tail);
bool iov_drop_header(struct iov_tail *tail, size_t len);
void *iov_peek_header_(struct iov_tail *tail, void *v, size_t len, size_t align);
+size_t iov_put_header_(struct iov_tail *tail, const void *v, size_t len);
void *iov_remove_header_(struct iov_tail *tail, void *v, size_t len, size_t align);
ssize_t iov_tail_clone(struct iovec *dst_iov, size_t dst_iov_cnt,
struct iov_tail *tail);
@@ -112,6 +113,16 @@ ssize_t iov_tail_clone(struct iovec *dst_iov, size_t dst_iov_cnt,
sizeof(var_), \
__alignof__(var_))))
+/**
+ * IOV_PUT_HEADER() - Write header back to an IOV tail
+ * @tail_: IOV tail to write header to
+ * @var_: Pointer to a variable containing the header data to write
+ *
+ * Return: number of bytes written
+ */
+#define IOV_PUT_HEADER(tail_, var_) \
+ (iov_put_header_((tail_), (var_), sizeof(*var_)))
+
/**
* IOV_REMOVE_HEADER() - Remove and return typed header from an IOV tail
* @tail_: IOV tail to remove header from (modified)
@@ -130,7 +141,8 @@ ssize_t iov_tail_clone(struct iovec *dst_iov, size_t dst_iov_cnt,
((__typeof__(var_) *)(iov_remove_header_((tail_), &(var_), \
sizeof(var_), __alignof__(var_))))
-/** IOV_DROP_HEADER() - Remove a typed header from an IOV tail
+/**
+ * IOV_DROP_HEADER() - Remove a typed header from an IOV tail
* @tail_: IOV tail to remove header from (modified)
* @type_: Data type of the header to remove
*
--
2.53.0