qemu/0108-virtiofsd-add-definition-of-fuse_buf_writev.patch

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From: piaojun <piaojun@huawei.com>
Date: Mon, 27 Jan 2020 19:02:17 +0000
Subject: [PATCH] virtiofsd: add definition of fuse_buf_writev()
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Define fuse_buf_writev() which use pwritev and writev to improve io
bandwidth. Especially, the src bufs with 0 size should be skipped as
their mems are not *block_size* aligned which will cause writev failed
in direct io mode.
Signed-off-by: Jun Piao <piaojun@huawei.com>
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
(cherry picked from commit 9ceaaa15cf21073c2b23058c374f61c30cd39c31)
---
tools/virtiofsd/buffer.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/tools/virtiofsd/buffer.c b/tools/virtiofsd/buffer.c
index 42a608f6bd..37befebac2 100644
--- a/tools/virtiofsd/buffer.c
+++ b/tools/virtiofsd/buffer.c
@@ -14,6 +14,7 @@
#include "fuse_lowlevel.h"
#include <assert.h>
#include <errno.h>
+#include <stdlib.h>
#include <string.h>
#include <unistd.h>
@@ -33,6 +34,43 @@ size_t fuse_buf_size(const struct fuse_bufvec *bufv)
return size;
}
+__attribute__((unused))
+static ssize_t fuse_buf_writev(struct fuse_buf *out_buf,
+ struct fuse_bufvec *in_buf)
+{
+ ssize_t res, i, j;
+ size_t iovcnt = in_buf->count;
+ struct iovec *iov;
+ int fd = out_buf->fd;
+
+ iov = calloc(iovcnt, sizeof(struct iovec));
+ if (!iov) {
+ return -ENOMEM;
+ }
+
+ for (i = 0, j = 0; i < iovcnt; i++) {
+ /* Skip the buf with 0 size */
+ if (in_buf->buf[i].size) {
+ iov[j].iov_base = in_buf->buf[i].mem;
+ iov[j].iov_len = in_buf->buf[i].size;
+ j++;
+ }
+ }
+
+ if (out_buf->flags & FUSE_BUF_FD_SEEK) {
+ res = pwritev(fd, iov, iovcnt, out_buf->pos);
+ } else {
+ res = writev(fd, iov, iovcnt);
+ }
+
+ if (res == -1) {
+ res = -errno;
+ }
+
+ free(iov);
+ return res;
+}
+
static size_t min_size(size_t s1, size_t s2)
{
return s1 < s2 ? s1 : s2;