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From: Vivek Goyal <vgoyal@redhat.com>
To: qemu-devel@nongnu.org, virtio-fs@redhat.com
Cc: dgilbert@redhat.com, vgoyal@redhat.com
Subject: [PATCH 4/7] virtiofsd: get rid of in_sg_left variable
Date: Tue, 11 May 2021 17:37:33 -0400	[thread overview]
Message-ID: <20210511213736.281016-5-vgoyal@redhat.com> (raw)
In-Reply-To: <20210511213736.281016-1-vgoyal@redhat.com>

in_sg_left seems to be being used primarly for debugging purpose. It is
keeping track of how many bytes are left in the scatter list we are
reading into.

We already have another variable "len" which keeps track how many bytes
are left to be read. And in_sg_left is greater than or equal to len. We
have already ensured that in the beginning of function.

    if (in_len < tosend_len) {
        fuse_log(FUSE_LOG_ERR, "%s: elem %d too small for data len %zd\n",
                 __func__, elem->index, tosend_len);
        ret = E2BIG;
        goto err;
    }

So in_sg_left seems like a redundant variable. It probably was useful for
debugging when code was being developed. Get rid of it. It helps simplify
this function.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 tools/virtiofsd/fuse_virtio.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index d56b225800..ccad2b3f8a 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -394,20 +394,16 @@ int virtio_send_data_iov(struct fuse_session *se, struct fuse_chan *ch,
     /* skip over parts of in_sg that contained the header iov */
     size_t skip_size = iov_len;
 
-    size_t in_sg_left = 0;
     do {
         if (skip_size != 0) {
 	    iov_discard_front(&in_sg_ptr, &in_sg_cpy_count, skip_size);
         }
 
-        int i;
-        for (i = 0, in_sg_left = 0; i < in_sg_cpy_count; i++) {
-            in_sg_left += in_sg_ptr[i].iov_len;
-        }
         fuse_log(FUSE_LOG_DEBUG,
                  "%s: after skip skip_size=%zd in_sg_cpy_count=%d "
-                 "in_sg_left=%zd\n",
-                 __func__, skip_size, in_sg_cpy_count, in_sg_left);
+                 "len remaining=%zd\n", __func__, skip_size, in_sg_cpy_count,
+                 len);
+
         ret = preadv(buf->buf[0].fd, in_sg_ptr, in_sg_cpy_count,
                      buf->buf[0].pos);
 
@@ -434,13 +430,12 @@ int virtio_send_data_iov(struct fuse_session *se, struct fuse_chan *ch,
         }
         if (!ret) {
             /* EOF case? */
-            fuse_log(FUSE_LOG_DEBUG, "%s: !ret in_sg_left=%zd\n", __func__,
-                     in_sg_left);
+            fuse_log(FUSE_LOG_DEBUG, "%s: !ret len remaining=%zd\n", __func__,
+                     len);
             break;
         }
-        in_sg_left -= ret;
         len -= ret;
-    } while (in_sg_left);
+    } while (len);
 
     /* Need to fix out->len on EOF */
     if (len) {
-- 
2.25.4



  parent reply	other threads:[~2021-05-11 21:41 UTC|newest]

Thread overview: 21+ 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 ` [PATCH 1/7] virtiofsd: Check for EINTR in preadv() and retry Vivek Goyal
2021-05-18 11:59   ` Dr. David Alan Gilbert
2021-05-11 21:37 ` [PATCH 2/7] virtiofsd: Get rid of unreachable code in read Vivek Goyal
2021-05-18 12:01   ` Dr. David Alan Gilbert
2021-05-11 21:37 ` [PATCH 3/7] virtiofsd: Use iov_discard_front() to skip bytes Vivek Goyal
2021-05-18 12:10   ` Dr. David Alan Gilbert
2021-05-11 21:37 ` Vivek Goyal [this message]
2021-05-18 12:19   ` [PATCH 4/7] virtiofsd: get rid of in_sg_left variable Dr. David Alan Gilbert
2021-05-11 21:37 ` [PATCH 5/7] virtiofsd: Simplify skip byte logic Vivek Goyal
2021-05-18 12:26   ` Dr. David Alan Gilbert
2021-05-11 21:37 ` [PATCH 6/7] virtiofsd: Check EOF before short read Vivek Goyal
2021-05-18 12:31   ` Dr. David Alan Gilbert
2021-05-11 21:37 ` [PATCH 7/7] virtiofsd: Set req->reply_sent right after sending reply Vivek Goyal
2021-05-13 20:50   ` [Virtio-fs] " Connor Kuehl
2021-05-17 13:08     ` Vivek Goyal
2021-05-18 12:34       ` Dr. David Alan Gilbert
2021-05-18 12:32   ` Dr. David Alan Gilbert
2021-05-11 21:48 ` [PATCH 0/7] virtiofsd: Few cleanups in virtio_send_data_iov() no-reply
2021-05-13 20:50 ` [Virtio-fs] " Connor Kuehl
2021-05-17 13:08   ` Vivek Goyal

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