From: Vivek Goyal <vgoyal@redhat.com> To: qemu-devel@nongnu.org, virtio-fs@redhat.com Cc: dgilbert@redhat.com, vgoyal@redhat.com Subject: [PATCH 5/7] virtiofsd: Simplify skip byte logic Date: Tue, 11 May 2021 17:37:34 -0400 [thread overview] Message-ID: <20210511213736.281016-6-vgoyal@redhat.com> (raw) In-Reply-To: <20210511213736.281016-1-vgoyal@redhat.com> 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. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> --- tools/virtiofsd/fuse_virtio.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c index ccad2b3f8a..434fe401cf 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; -- 2.25.4
WARNING: multiple messages have this Message-ID (diff)
From: Vivek Goyal <vgoyal@redhat.com> To: qemu-devel@nongnu.org, virtio-fs@redhat.com Cc: vgoyal@redhat.com Subject: [Virtio-fs] [PATCH 5/7] virtiofsd: Simplify skip byte logic Date: Tue, 11 May 2021 17:37:34 -0400 [thread overview] Message-ID: <20210511213736.281016-6-vgoyal@redhat.com> (raw) In-Reply-To: <20210511213736.281016-1-vgoyal@redhat.com> 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. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> --- tools/virtiofsd/fuse_virtio.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c index ccad2b3f8a..434fe401cf 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; -- 2.25.4
next prev parent reply other threads:[~2021-05-11 21:39 UTC|newest] Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-11 21:37 [PATCH 0/7] virtiofsd: Few cleanups in virtio_send_data_iov() Vivek Goyal 2021-05-11 21:37 ` [Virtio-fs] " Vivek Goyal 2021-05-11 21:37 ` [PATCH 1/7] virtiofsd: Check for EINTR in preadv() and retry Vivek Goyal 2021-05-11 21:37 ` [Virtio-fs] " Vivek Goyal 2021-05-18 11:59 ` Dr. David Alan Gilbert 2021-05-18 11:59 ` [Virtio-fs] " Dr. David Alan Gilbert 2021-05-11 21:37 ` [PATCH 2/7] virtiofsd: Get rid of unreachable code in read Vivek Goyal 2021-05-11 21:37 ` [Virtio-fs] " Vivek Goyal 2021-05-18 12:01 ` Dr. David Alan Gilbert 2021-05-18 12:01 ` [Virtio-fs] " Dr. David Alan Gilbert 2021-05-11 21:37 ` [PATCH 3/7] virtiofsd: Use iov_discard_front() to skip bytes Vivek Goyal 2021-05-11 21:37 ` [Virtio-fs] " Vivek Goyal 2021-05-18 12:10 ` Dr. David Alan Gilbert 2021-05-18 12:10 ` [Virtio-fs] " Dr. David Alan Gilbert 2021-05-11 21:37 ` [PATCH 4/7] virtiofsd: get rid of in_sg_left variable Vivek Goyal 2021-05-11 21:37 ` [Virtio-fs] " Vivek Goyal 2021-05-18 12:19 ` Dr. David Alan Gilbert 2021-05-18 12:19 ` [Virtio-fs] " Dr. David Alan Gilbert 2021-05-11 21:37 ` Vivek Goyal [this message] 2021-05-11 21:37 ` [Virtio-fs] [PATCH 5/7] virtiofsd: Simplify skip byte logic Vivek Goyal 2021-05-18 12:26 ` Dr. David Alan Gilbert 2021-05-18 12:26 ` [Virtio-fs] " Dr. David Alan Gilbert 2021-05-11 21:37 ` [PATCH 6/7] virtiofsd: Check EOF before short read Vivek Goyal 2021-05-11 21:37 ` [Virtio-fs] " Vivek Goyal 2021-05-18 12:31 ` Dr. David Alan Gilbert 2021-05-18 12:31 ` [Virtio-fs] " Dr. David Alan Gilbert 2021-05-11 21:37 ` [PATCH 7/7] virtiofsd: Set req->reply_sent right after sending reply Vivek Goyal 2021-05-11 21:37 ` [Virtio-fs] " Vivek Goyal 2021-05-13 20:50 ` Connor Kuehl 2021-05-17 13:08 ` Vivek Goyal 2021-05-18 12:34 ` Dr. David Alan Gilbert 2021-05-18 12:34 ` Dr. David Alan Gilbert 2021-05-18 12:32 ` Dr. David Alan Gilbert 2021-05-18 12:32 ` [Virtio-fs] " Dr. David Alan Gilbert 2021-05-11 21:48 ` [PATCH 0/7] virtiofsd: Few cleanups in virtio_send_data_iov() no-reply 2021-05-11 21:48 ` [Virtio-fs] " no-reply 2021-05-13 20:50 ` Connor Kuehl 2021-05-17 13:08 ` Vivek Goyal
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