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iov: Add iov_to_buf and iov_size helpers 

iov_to_buf() puts the buffer contents in the iov in a linearized buffer.

iov_size() gets the length of the contents in the iov.

The iov_to_buf() function is the memcpy_to_iovec() function that was
used in virtio-ballon.c.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Amit Shah 2010-04-27 18:04:06 +05:30 committed by Anthony Liguori
parent e4d5639dbb
commit fa6111f215
3 changed files with 44 additions and 31 deletions
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37
hw/iov.c
View File

@ -31,3 +31,40 @@ size_t iov_from_buf(struct iovec *iov, unsigned int iovcnt,
}
return offset;
}
size_t iov_to_buf(const struct iovec *iov, const unsigned int iovcnt,
void *buf, size_t offset, size_t size)
{
uint8_t *ptr;
size_t iov_off, buf_off;
unsigned int i;
ptr = buf;
iov_off = 0;
buf_off = 0;
for (i = 0; i < iovcnt && size; i++) {
if (offset < (iov_off + iov[i].iov_len)) {
size_t len = MIN((iov_off + iov[i].iov_len) - offset , size);
memcpy(ptr + buf_off, iov[i].iov_base + (offset - iov_off), len);
buf_off += len;
offset += len;
size -= len;
}
iov_off += iov[i].iov_len;
}
return buf_off;
}
size_t iov_size(const struct iovec *iov, const unsigned int iovcnt)
{
size_t len;
unsigned int i;
len = 0;
for (i = 0; i < iovcnt; i++) {
len += iov[i].iov_len;
}
return len;
}

3
hw/iov.h
View File

@ -14,3 +14,6 @@
size_t iov_from_buf(struct iovec *iov, unsigned int iovcnt,
const void *buf, size_t size);
size_t iov_to_buf(const struct iovec *iov, const unsigned int iovcnt,
void *buf, size_t offset, size_t size);
size_t iov_size(const struct iovec *iov, const unsigned int iovcnt);

35
hw/virtio-balloon.c
View File

@ -11,6 +11,7 @@
*
*/
#include "iov.h"
#include "qemu-common.h"
#include "virtio.h"
#include "pc.h"
@ -92,33 +93,6 @@ static QObject *get_stats_qobject(VirtIOBalloon *dev)
return QOBJECT(dict);
}
/* FIXME: once we do a virtio refactoring, this will get subsumed into common
* code */
static size_t memcpy_from_iovector(void *data, size_t offset, size_t size,
struct iovec *iov, int iovlen)
{
int i;
uint8_t *ptr = data;
size_t iov_off = 0;
size_t data_off = 0;
for (i = 0; i < iovlen && size; i++) {
if (offset < (iov_off + iov[i].iov_len)) {
size_t len = MIN((iov_off + iov[i].iov_len) - offset , size);
memcpy(ptr + data_off, iov[i].iov_base + (offset - iov_off), len);
data_off += len;
offset += len;
size -= len;
}
iov_off += iov[i].iov_len;
}
return data_off;
}
static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOBalloon *s = to_virtio_balloon(vdev);
@ -128,8 +102,7 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
size_t offset = 0;
uint32_t pfn;
while (memcpy_from_iovector(&pfn, offset, 4,
elem.out_sg, elem.out_num) == 4) {
while (iov_to_buf(elem.out_sg, elem.out_num, &pfn, offset, 4) == 4) {
ram_addr_t pa;
ram_addr_t addr;
@ -181,8 +154,8 @@ static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
*/
reset_stats(s);
while (memcpy_from_iovector(&stat, offset, sizeof(stat), elem->out_sg,
elem->out_num) == sizeof(stat)) {
while (iov_to_buf(elem->out_sg, elem->out_num, &stat, offset, sizeof(stat))
== sizeof(stat)) {
uint16_t tag = tswap16(stat.tag);
uint64_t val = tswap64(stat.val);