...and, for consistency, rename 'bytes' to 'copy' in iov_to_buf().
Two commits ago, I changed vhost-user functions to use iov_from_buf()
to copy only up to the size of source buffers, instead of using the
size of the destination vhost-user buffers.
This change pads the rest with zeroes, which is not strictly needed,
but looks definitely cleaner.
Signed-off-by: Stefano Brivio
---
iov.c | 54 ++++++++++++++++++++++++++++++++++-------------------
iov.h | 4 ++--
vu_common.c | 2 +-
3 files changed, 38 insertions(+), 22 deletions(-)
diff --git a/iov.c b/iov.c
index dc1b6b1..557be55 100644
--- a/iov.c
+++ b/iov.c
@@ -59,35 +59,51 @@ size_t iov_skip_bytes(const struct iovec *iov, size_t n,
* @iov_cnt: Number of elements in the iovec array
* @offset: Destination offset in iovec array
* @buf: Source buffer
- * @bytes: Bytes to copy
+ * @copy: Bytes to copy
+ * @fill: Bytes to zero-fill after copied bytes
*
- * Return: number of bytes copied
+ * Return: number of bytes filled, with data or zeroes
*/
size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
- size_t offset, const void *buf, size_t bytes)
+ size_t offset, const void *buf, size_t copy, size_t fill)
{
+ size_t copied, filled;
unsigned int i;
- size_t copied;
- if (__builtin_constant_p(bytes) && iov_cnt &&
- offset <= iov[0].iov_len && bytes <= iov[0].iov_len - offset) {
- memcpy((char *)iov[0].iov_base + offset, buf, bytes);
+ if (__builtin_constant_p(copy) && iov_cnt &&
+ offset <= iov[0].iov_len &&
+ (copy + fill) <= iov[0].iov_len - offset) {
+ memcpy((char *)iov[0].iov_base + offset, buf, copy);
+ memset((char *)iov[0].iov_base + offset + copy, 0, fill);
- return bytes;
+ return copy + fill;
}
i = iov_skip_bytes(iov, iov_cnt, offset, &offset);
- for (copied = 0; copied < bytes && i < iov_cnt; i++) {
- size_t len = MIN(iov[i].iov_len - offset, bytes - copied);
+ for (copied = 0; copied < copy && i < iov_cnt; i++) {
+ size_t len = MIN(iov[i].iov_len - offset, copy - copied);
memcpy((char *)iov[i].iov_base + offset, (char *)buf + copied,
len);
copied += len;
+
+ if (copied < copy)
+ offset = 0; /* More to copy in the next iteration */
+ else
+ offset = len; /* Start of zero-filling, see below */
+ }
+
+ for (filled = 0; filled < fill && i < iov_cnt; i++) {
+ size_t len = MIN(iov[i].iov_len - offset, fill - filled);
+
+ memcpy((char *)iov[i].iov_base + offset,
+ (char *)buf + copied + filled, len);
+ filled += len;
offset = 0;
}
- return copied;
+ return copied + filled;
}
/**
@@ -96,27 +112,27 @@ size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
* @iov_cnt: Number of elements in iovec array
* @offset: Source offset altogether, counted in flattened iovec
* @buf: Destination buffer
- * @bytes: Bytes to copy
+ * @copy: Bytes to copy
*
* Return: number of bytes copied
*/
size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
- size_t offset, void *buf, size_t bytes)
+ size_t offset, void *buf, size_t copy)
{
unsigned int i;
size_t copied;
- if (__builtin_constant_p(bytes) && iov_cnt &&
- offset <= iov[0].iov_len && bytes <= iov[0].iov_len - offset) {
- memcpy(buf, (char *)iov[0].iov_base + offset, bytes);
+ if (__builtin_constant_p(copy) && iov_cnt &&
+ offset <= iov[0].iov_len && copy <= iov[0].iov_len - offset) {
+ memcpy(buf, (char *)iov[0].iov_base + offset, copy);
- return bytes;
+ return copy;
}
i = iov_skip_bytes(iov, iov_cnt, offset, &offset);
- for (copied = 0; copied < bytes && i < iov_cnt; i++) {
- size_t len = MIN(iov[i].iov_len - offset, bytes - copied);
+ for (copied = 0; copied < copy && i < iov_cnt; i++) {
+ size_t len = MIN(iov[i].iov_len - offset, copy - copied);
ASSERT(iov[i].iov_base);
diff --git a/iov.h b/iov.h
index ba1fda5..9b5d910 100644
--- a/iov.h
+++ b/iov.h
@@ -24,9 +24,9 @@
size_t iov_skip_bytes(const struct iovec *iov, size_t n,
size_t skip, size_t *offset);
size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
- size_t offset, const void *buf, size_t bytes);
+ size_t offset, const void *buf, size_t copy, size_t fill);
size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
- size_t offset, void *buf, size_t bytes);
+ size_t offset, void *buf, size_t copy);
size_t iov_size(const struct iovec *iov, size_t iov_cnt);
/*
diff --git a/vu_common.c b/vu_common.c
index 21cfb2a..d941b72 100644
--- a/vu_common.c
+++ b/vu_common.c
@@ -274,7 +274,7 @@ int vu_send_single(const struct ctx *c, const void *buf, size_t size)
/* copy data from the buffer to the iovec */
iov_from_buf(in_sg, elem_cnt, sizeof(struct virtio_net_hdr_mrg_rxbuf),
- buf, size);
+ buf, size, vu_buf_size - size);
if (*c->pcap) {
pcap_iov(in_sg, elem_cnt,
--
2.43.0