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authorHanna Czenczek <hreitz@redhat.com>2023-04-11 19:34:17 +0200
committerHanna Czenczek <hreitz@redhat.com>2023-06-05 13:11:24 +0200
commitcc63f6f6fa1aaa4b6405dd69432c693e9c8d18ca (patch)
treee3528fd018b77cc34d60cf0cb28b7914c54adc61 /util/iov.c
parent18743311b829cafc1737a5f20bc3248d5f91ee2a (diff)
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util/iov: Remove qemu_iovec_init_extended()
bdrv_pad_request() was the main user of qemu_iovec_init_extended(). HEAD^ has removed that use, so we can remove qemu_iovec_init_extended() now. The only remaining user is qemu_iovec_init_slice(), which can easily inline the small part it really needs. Note that qemu_iovec_init_extended() offered a memcpy() optimization to initialize the new I/O vector. qemu_iovec_concat_iov(), which is used to replace its functionality, does not, but calls qemu_iovec_add() for every single element. If we decide this optimization was important, we will need to re-implement it in qemu_iovec_concat_iov(), which might also benefit its pre-existing users. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Signed-off-by: Hanna Czenczek <hreitz@redhat.com> Message-Id: <20230411173418.19549-4-hreitz@redhat.com>
Diffstat (limited to 'util/iov.c')
-rw-r--r--util/iov.c79
1 files changed, 11 insertions, 68 deletions
diff --git a/util/iov.c b/util/iov.c
index 65a7044..866fb57 100644
--- a/util/iov.c
+++ b/util/iov.c
@@ -417,70 +417,6 @@ int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len)
}
/*
- * Compile new iovec, combining @head_buf buffer, sub-qiov of @mid_qiov,
- * and @tail_buf buffer into new qiov.
- */
-int qemu_iovec_init_extended(
- QEMUIOVector *qiov,
- void *head_buf, size_t head_len,
- QEMUIOVector *mid_qiov, size_t mid_offset, size_t mid_len,
- void *tail_buf, size_t tail_len)
-{
- size_t mid_head, mid_tail;
- int total_niov, mid_niov = 0;
- struct iovec *p, *mid_iov = NULL;
-
- assert(mid_qiov->niov <= IOV_MAX);
-
- if (SIZE_MAX - head_len < mid_len ||
- SIZE_MAX - head_len - mid_len < tail_len)
- {
- return -EINVAL;
- }
-
- if (mid_len) {
- mid_iov = qemu_iovec_slice(mid_qiov, mid_offset, mid_len,
- &mid_head, &mid_tail, &mid_niov);
- }
-
- total_niov = !!head_len + mid_niov + !!tail_len;
- if (total_niov > IOV_MAX) {
- return -EINVAL;
- }
-
- if (total_niov == 1) {
- qemu_iovec_init_buf(qiov, NULL, 0);
- p = &qiov->local_iov;
- } else {
- qiov->niov = qiov->nalloc = total_niov;
- qiov->size = head_len + mid_len + tail_len;
- p = qiov->iov = g_new(struct iovec, qiov->niov);
- }
-
- if (head_len) {
- p->iov_base = head_buf;
- p->iov_len = head_len;
- p++;
- }
-
- assert(!mid_niov == !mid_len);
- if (mid_niov) {
- memcpy(p, mid_iov, mid_niov * sizeof(*p));
- p[0].iov_base = (uint8_t *)p[0].iov_base + mid_head;
- p[0].iov_len -= mid_head;
- p[mid_niov - 1].iov_len -= mid_tail;
- p += mid_niov;
- }
-
- if (tail_len) {
- p->iov_base = tail_buf;
- p->iov_len = tail_len;
- }
-
- return 0;
-}
-
-/*
* Check if the contents of subrange of qiov data is all zeroes.
*/
bool qemu_iovec_is_zero(QEMUIOVector *qiov, size_t offset, size_t bytes)
@@ -511,14 +447,21 @@ bool qemu_iovec_is_zero(QEMUIOVector *qiov, size_t offset, size_t bytes)
void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source,
size_t offset, size_t len)
{
- int ret;
+ struct iovec *slice_iov;
+ int slice_niov;
+ size_t slice_head, slice_tail;
assert(source->size >= len);
assert(source->size - len >= offset);
- /* We shrink the request, so we can't overflow neither size_t nor MAX_IOV */
- ret = qemu_iovec_init_extended(qiov, NULL, 0, source, offset, len, NULL, 0);
- assert(ret == 0);
+ slice_iov = qemu_iovec_slice(source, offset, len,
+ &slice_head, &slice_tail, &slice_niov);
+ if (slice_niov == 1) {
+ qemu_iovec_init_buf(qiov, slice_iov[0].iov_base + slice_head, len);
+ } else {
+ qemu_iovec_init(qiov, slice_niov);
+ qemu_iovec_concat_iov(qiov, slice_iov, slice_niov, slice_head, len);
+ }
}
void qemu_iovec_destroy(QEMUIOVector *qiov)