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authorVivek Goyal <vgoyal@redhat.com>2021-05-18 17:35:36 -0400
committerDr. David Alan Gilbert <dgilbert@redhat.com>2021-05-26 18:39:32 +0100
commitbf7a3ee04430dfe426eacf6ee587e2a069ba67ce (patch)
treebc1125995730bf3524518502235c199b9e15b22b /tools/virtiofsd
parent0106f6f234d6361bb99cabfa48a953c929a3ca90 (diff)
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virtiofsd: Simplify skip byte logic
We need to skip bytes in two cases. a. Before we start reading into in_sg, we need to skip iov_len bytes in the beginning which typically will have fuse_out_header. b. If preadv() does a short read, then we need to retry preadv() with remainig bytes and skip the bytes preadv() read in short read. For case a, there is no reason that skipping logic be inside the while loop. Move it outside. And only retain logic "b" inside while loop. Also get rid of variable "skip_size". Looks like we can do without it. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Connor Kuehl <ckuehl@redhat.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Message-Id: <20210518213538.693422-6-vgoyal@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Diffstat (limited to 'tools/virtiofsd')
-rw-r--r--tools/virtiofsd/fuse_virtio.c14
1 files changed, 4 insertions, 10 deletions
diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index ed5146d..49c7dd7 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -392,17 +392,11 @@ int virtio_send_data_iov(struct fuse_session *se, struct fuse_chan *ch,
unsigned int in_sg_cpy_count = in_num;
/* skip over parts of in_sg that contained the header iov */
- size_t skip_size = iov_len;
+ iov_discard_front(&in_sg_ptr, &in_sg_cpy_count, iov_len);
do {
- if (skip_size != 0) {
- iov_discard_front(&in_sg_ptr, &in_sg_cpy_count, skip_size);
- }
-
- fuse_log(FUSE_LOG_DEBUG,
- "%s: after skip skip_size=%zd in_sg_cpy_count=%d "
- "len remaining=%zd\n", __func__, skip_size, in_sg_cpy_count,
- len);
+ fuse_log(FUSE_LOG_DEBUG, "%s: in_sg_cpy_count=%d len remaining=%zd\n",
+ __func__, in_sg_cpy_count, len);
ret = preadv(buf->buf[0].fd, in_sg_ptr, in_sg_cpy_count,
buf->buf[0].pos);
@@ -421,7 +415,7 @@ int virtio_send_data_iov(struct fuse_session *se, struct fuse_chan *ch,
if (ret < len && ret) {
fuse_log(FUSE_LOG_DEBUG, "%s: ret < len\n", __func__);
/* Skip over this much next time around */
- skip_size = ret;
+ iov_discard_front(&in_sg_ptr, &in_sg_cpy_count, ret);
buf->buf[0].pos += ret;
len -= ret;