+++ /dev/null
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Stefan Reiter <s.reiter@proxmox.com>
-Date: Wed, 9 Dec 2020 11:46:57 +0100
-Subject: [PATCH] PVE: block/pbs: fast-path reads without allocation if
- possible
-
-...and switch over to g_malloc/g_free while at it to align with other
-QEMU code.
-
-Tracing shows the fast-path is taken almost all the time, though not
-100% so the slow one is still necessary.
-
-Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
-Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
----
- block/pbs.c | 17 ++++++++++++++---
- 1 file changed, 14 insertions(+), 3 deletions(-)
-
-diff --git a/block/pbs.c b/block/pbs.c
-index 0b05ea9080..c5eb4d5bad 100644
---- a/block/pbs.c
-+++ b/block/pbs.c
-@@ -200,7 +200,16 @@ static coroutine_fn int pbs_co_preadv(BlockDriverState *bs,
- BDRVPBSState *s = bs->opaque;
- int ret;
- char *pbs_error = NULL;
-- uint8_t *buf = malloc(bytes);
-+ uint8_t *buf;
-+ bool inline_buf = true;
-+
-+ /* for single-buffer IO vectors we can fast-path the write directly to it */
-+ if (qiov->niov == 1 && qiov->iov->iov_len >= bytes) {
-+ buf = qiov->iov->iov_base;
-+ } else {
-+ inline_buf = false;
-+ buf = g_malloc(bytes);
-+ }
-
- if (offset < 0 || bytes < 0) {
- fprintf(stderr, "unexpected negative 'offset' or 'bytes' value!\n");
-@@ -223,8 +232,10 @@ static coroutine_fn int pbs_co_preadv(BlockDriverState *bs,
- return -EIO;
- }
-
-- qemu_iovec_from_buf(qiov, 0, buf, bytes);
-- free(buf);
-+ if (!inline_buf) {
-+ qemu_iovec_from_buf(qiov, 0, buf, bytes);
-+ g_free(buf);
-+ }
-
- return ret;
- }