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[Qemu-block] [RFC PATCH] block: local qiov helper
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[Qemu-block] [RFC PATCH] block: local qiov helper |
Date: |
Fri, 25 Jan 2019 19:46:01 +0300 |
Hi all.
What about such a simple helper for a very often patter around
qemu_iovec_init_external ?
If we like it, I'll update other callers of qemu_iovec_init_external.
Possible interface change would be
LOCAL_QIOV(lc, buf, len);
instead of
LocalQiov lc = LOCAL_QIOV(lc, buf, len);
or, may be, someone has a better idea?
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
include/qemu/iov.h | 19 +++++++++++++++++++
block/io.c | 9 ++-------
2 files changed, 21 insertions(+), 7 deletions(-)
diff --git a/include/qemu/iov.h b/include/qemu/iov.h
index 5f433c7768..e0963d8ebe 100644
--- a/include/qemu/iov.h
+++ b/include/qemu/iov.h
@@ -137,6 +137,25 @@ typedef struct QEMUIOVector {
size_t size;
} QEMUIOVector;
+typedef struct LocalQiov {
+ QEMUIOVector qiov;
+ struct iovec iov;
+} LocalQiov;
+
+#define LOCAL_QIOV(self, buf, len) \
+{ \
+ .qiov = { \
+ .iov = &self.iov, \
+ .size = len, \
+ .niov = 1, \
+ .nalloc = -1 \
+ }, \
+ .iov = { \
+ .iov_base = (void *)(buf), \
+ .iov_len = len \
+ } \
+}
+
void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint);
void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov);
void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len);
diff --git a/block/io.c b/block/io.c
index bd9d688f8b..c7d7b199c1 100644
--- a/block/io.c
+++ b/block/io.c
@@ -949,18 +949,13 @@ int bdrv_preadv(BdrvChild *child, int64_t offset,
QEMUIOVector *qiov)
int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes)
{
- QEMUIOVector qiov;
- struct iovec iov = {
- .iov_base = (void *)buf,
- .iov_len = bytes,
- };
+ LocalQiov lq = LOCAL_QIOV(lq, buf, bytes);
if (bytes < 0) {
return -EINVAL;
}
- qemu_iovec_init_external(&qiov, &iov, 1);
- return bdrv_preadv(child, offset, &qiov);
+ return bdrv_preadv(child, offset, &lq.qiov);
}
int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov)
--
2.18.0
- [Qemu-block] [RFC PATCH] block: local qiov helper,
Vladimir Sementsov-Ogievskiy <=