Similar to
qemu_iovec_memset(QEMUIOVector *qiov, size_t offset, int c, size_t bytes);
the new prototype is:
qemu_iovec_from_buffer(QEMUIOVector *qiov, size_t offset, const void *buf,
size_t bytes);
The processing starts at offset bytes within qiov.
This way, we may copy a bounce buffer directly to a middle of qiov.
While at it, add some asserts to ensure that buffer content fits
within qiov: offset + bytes <= size.
---
block.c | 4 ++--
block/curl.c | 4 ++--
block/qcow.c | 2 +-
block/qcow2.c | 4 ++--
block/vdi.c | 2 +-
cutils.c | 27 +++++++++++++++++----------
qemu-common.h | 3 ++-
7 files changed, 27 insertions(+), 19 deletions(-)
diff --git a/block.c b/block.c
index 52ffe14..cbbedfa 100644
--- a/block.c
+++ b/block.c
@@ -1692,7 +1692,7 @@ static int coroutine_fn
bdrv_co_do_copy_on_readv(BlockDriverState *bs,
}
skip_bytes = (sector_num - cluster_sector_num) * BDRV_SECTOR_SIZE;
- qemu_iovec_from_buffer(qiov, bounce_buffer + skip_bytes,
+ qemu_iovec_from_buffer(qiov, 0, bounce_buffer + skip_bytes,
nb_sectors * BDRV_SECTOR_SIZE);
err:
@@ -3240,7 +3240,7 @@ static void bdrv_aio_bh_cb(void *opaque)
BlockDriverAIOCBSync *acb = opaque;
if (!acb->is_write)
- qemu_iovec_from_buffer(acb->qiov, acb->bounce, acb->qiov->size);
+ qemu_iovec_from_buffer(acb->qiov, 0, acb->bounce, acb->qiov->size);
qemu_vfree(acb->bounce);
acb->common.cb(acb->common.opaque, acb->ret);
qemu_bh_delete(acb->bh);
diff --git a/block/curl.c b/block/curl.c
index e9102e3..e772912 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -142,7 +142,7 @@ static size_t curl_read_cb(void *ptr, size_t size, size_t
nmemb, void *opaque)
continue;
if ((s->buf_off >= acb->end)) {
- qemu_iovec_from_buffer(acb->qiov, s->orig_buf + acb->start,
+ qemu_iovec_from_buffer(acb->qiov, 0, s->orig_buf + acb->start,
acb->end - acb->start);
acb->common.cb(acb->common.opaque, 0);
qemu_aio_release(acb);
@@ -178,7 +178,7 @@ static int curl_find_buf(BDRVCURLState *s, size_t start,
size_t len,
{
char *buf = state->orig_buf + (start - state->buf_start);
- qemu_iovec_from_buffer(acb->qiov, buf, len);
+ qemu_iovec_from_buffer(acb->qiov, 0, buf, len);
acb->common.cb(acb->common.opaque, 0);
return FIND_RET_OK;
diff --git a/block/qcow.c b/block/qcow.c
index b1cfe1f..f95b93f 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -540,7 +540,7 @@ done:
qemu_co_mutex_unlock(&s->lock);
if (qiov->niov > 1) {
- qemu_iovec_from_buffer(qiov, orig_buf, qiov->size);
+ qemu_iovec_from_buffer(qiov, 0, orig_buf, qiov->size);
qemu_vfree(orig_buf);
}
diff --git a/block/qcow2.c b/block/qcow2.c
index 6d11bc0..668e2e2 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -475,7 +475,7 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState
*bs, int64_t sector_num,
goto fail;
}
- qemu_iovec_from_buffer(&hd_qiov,
+ qemu_iovec_from_buffer(&hd_qiov, 0,
s->cluster_cache + index_in_cluster * 512,
512 * cur_nr_sectors);
} else {
@@ -516,7 +516,7 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState
*bs, int64_t sector_num,
qemu_iovec_reset(&hd_qiov);
qemu_iovec_copy(&hd_qiov, qiov, bytes_done,
cur_nr_sectors * 512);
- qemu_iovec_from_buffer(&hd_qiov, cluster_data,
+ qemu_iovec_from_buffer(&hd_qiov, 0, cluster_data,
512 * cur_nr_sectors);
}
}
diff --git a/block/vdi.c b/block/vdi.c
index 6a0011f..db0650e 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -635,7 +635,7 @@ static void vdi_aio_read_cb(void *opaque, int ret)
return;
done:
if (acb->qiov->niov > 1) {
- qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size);
+ qemu_iovec_from_buffer(acb->qiov, 0, acb->orig_buf, acb->qiov->size);
qemu_vfree(acb->orig_buf);
}
acb->common.cb(acb->common.opaque, ret);
diff --git a/cutils.c b/cutils.c
index 9451c86..5353f89 100644
--- a/cutils.c
+++ b/cutils.c
@@ -244,19 +244,26 @@ void qemu_iovec_to_buffer(QEMUIOVector *qiov, void *buf)
}
}
-void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf, size_t count)
+void qemu_iovec_from_buffer(QEMUIOVector *qiov, size_t offset,
+ const void *buf, size_t bytes)
{
- const uint8_t *p = (const uint8_t *)buf;
- size_t copy;
+ const struct iovec *iov = qiov->iov;
int i;
+ assert(qiov->size >= offset);
+ assert(qiov->size - offset >= bytes);
- for (i = 0; i < qiov->niov && count; ++i) {
- copy = count;
- if (copy > qiov->iov[i].iov_len)
- copy = qiov->iov[i].iov_len;
- memcpy(qiov->iov[i].iov_base, p, copy);
- p += copy;
- count -= copy;
+ /* first skip initial full-sized elements */
+ for(i = 0; offset >= iov[i].iov_len; ++i) {
+ offset -= iov[i].iov_len;
+ }
+ /* skip/copy partial element and copy the rest */
+ while(bytes) {
+ size_t n = MIN(bytes, iov[i].iov_len - offset);
+ memcpy((char*)iov[i].iov_base + offset, buf, n);
+ bytes -= n;
+ buf = (const char*)buf + n;
+ ++i;
+ offset = 0;
}
}
diff --git a/qemu-common.h b/qemu-common.h
index a1ff126..249f70d 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -339,7 +339,8 @@ void qemu_iovec_concat(QEMUIOVector *dst, QEMUIOVector
*src, size_t size);
void qemu_iovec_destroy(QEMUIOVector *qiov);
void qemu_iovec_reset(QEMUIOVector *qiov);
void qemu_iovec_to_buffer(QEMUIOVector *qiov, void *buf);
-void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf, size_t count);
+void qemu_iovec_from_buffer(QEMUIOVector *qiov, size_t offset,
+ const void *buf, size_t bytes);
void qemu_iovec_memset(QEMUIOVector *qiov, size_t offset, int c, size_t bytes);
bool buffer_is_zero(const void *buf, size_t len);
--
1.7.9.1
