vmm_vhost: inline Endpoint::recv_data

Convenience methods like this aren't worth the mental overhead IMO.

Change-Id: I2c08cf64b781328f515b88373170c4506058814c
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/5066129
Commit-Queue: Frederick Mayle <fmayle@google.com>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>

third_party/vmm_vhost/src/connection.rs

@@ -240,19 +240,6 @@ impl<R: Req> Endpoint<R> {
         Ok(())
     }
 
-    /// Reads `len` bytes at most.
-    ///
-    /// # Return:
-    /// * - (number of bytes received, buf) on success
-    pub fn recv_data(&self, len: usize) -> Result<Vec<u8>> {
-        let mut buf = vec![0u8; len];
-        let (data_len, _) = self
-            .0
-            .recv_into_bufs(&mut [IoSliceMut::new(&mut buf)], false /* allow_fd */)?;
-        buf.truncate(data_len);
-        Ok(buf)
-    }
-
     /// Reads all bytes into the given scatter/gather vectors with optional attached files. Will
     /// loop until all data has been transfered and errors if EOF is reached before then.
     ///

third_party/vmm_vhost/src/connection/socket.rs

@@ -386,8 +386,8 @@ mod tests {
             .unwrap();
         assert_eq!(len, 4);
 
-        let buf4 = slave.recv_data(2).unwrap();
-        assert_eq!(buf4.len(), 2);
+        let mut buf4 = vec![0u8; 2];
+        slave.recv_into_bufs_all(&mut [&mut buf4[..]]).unwrap();
         assert_eq!(&buf1[..2], &buf4[..]);
         let (bytes, buf2, files) = slave.recv_into_buf(0x2).unwrap();
         assert_eq!(bytes, 2);
@@ -451,8 +451,9 @@ mod tests {
             .unwrap();
         assert_eq!(len, 4);
 
-        let v = slave.recv_data(5).unwrap();
-        assert_eq!(v.len(), 5);
+        let mut v = vec![0u8; 5];
+        slave.recv_into_bufs_all(&mut [&mut v[..]]).unwrap();
+        assert_eq!(&v[..], &[1, 2, 3, 4, 1]);
 
         let (bytes, _, files) = slave.recv_into_buf(0x4).unwrap();
         assert_eq!(bytes, 3);

third_party/vmm_vhost/src/master_req_handler.rs

@@ -303,16 +303,8 @@ impl<S: VhostUserMasterReqHandler> MasterReqHandler<S> {
         // . validate message body and optional payload
         let (hdr, files) = self.sub_sock.recv_header()?;
         self.check_attached_files(&hdr, &files)?;
-        let buf = match hdr.get_size() {
-            0 => vec![0u8; 0],
-            len => {
-                let rbuf = self.sub_sock.recv_data(len as usize)?;
-                if rbuf.len() != len as usize {
-                    return Err(Error::InvalidMessage);
-                }
-                rbuf
-            }
-        };
+        let mut buf = vec![0u8; hdr.get_size().try_into().unwrap()];
+        self.sub_sock.recv_into_bufs_all(&mut [&mut buf[..]])?;
         let size = buf.len();
 
         let res = match hdr.get_code() {

third_party/vmm_vhost/src/slave_req_handler.rs

@@ -667,16 +667,10 @@ impl<S: VhostUserSlaveReqHandler> SlaveReqHandler<S> {
         hdr: VhostUserMsgHeader<MasterReq>,
         files: Option<Vec<File>>,
     ) -> Result<()> {
-        let buf = match hdr.get_size() {
-            0 => vec![0u8; 0],
-            len => {
-                let rbuf = self.slave_req_helper.endpoint.recv_data(len as usize)?;
-                if rbuf.len() != len as usize {
-                    return Err(Error::InvalidMessage);
-                }
-                rbuf
-            }
-        };
+        let mut buf = vec![0u8; hdr.get_size().try_into().unwrap()];
+        self.slave_req_helper
+            .endpoint
+            .recv_into_bufs_all(&mut [&mut buf[..]])?;
         let size = buf.len();
 
         match hdr.get_code() {