Revert "Staging: dgrp: Refactor the function dgrp_receive() in drrp_net_ops.c"

This reverts commit b73db547.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: Rashika Kheria <rashika.kheria@gmail.com>
Cc: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/dgrp/dgrp_net_ops.c

@@ -2232,177 +2232,6 @@ static ssize_t dgrp_net_read(struct file *file, char __user *buf, size_t count,
 	return rtn;
 }
 
-/*
- * Common Packet Handling code
- */
-
-static void handle_data_in_packet(struct nd_struct *nd, struct ch_struct *ch,
-				  long dlen, long plen, int n1, u8 *dbuf)
-{
-	char *error;
-	long n;
-	long remain;
-	u8 *buf;
-	u8 *b;
-
-	remain = nd->nd_remain;
-	nd->nd_tx_work = 1;
-
-	/*
-	 *  Otherwise data should appear only when we are
-	 *  in the CS_READY state.
-	 */
-
-	if (ch->ch_state < CS_READY) {
-		error = "Data received before RWIN established";
-		nd->nd_remain = 0;
-		nd->nd_state = NS_SEND_ERROR;
-		nd->nd_error = error;
-	}
-
-	/*
-	 *  Assure that the data received is within the
-	 *  allowable window.
-	 */
-
-	n = (ch->ch_s_rwin - ch->ch_s_rin) & 0xffff;
-
-	if (dlen > n) {
-		error = "Receive data overrun";
-		nd->nd_remain = 0;
-		nd->nd_state = NS_SEND_ERROR;
-		nd->nd_error = error;
-	}
-
-	/*
-	 *  If we received 3 or less characters,
-	 *  assume it is a human typing, and set RTIME
-	 *  to 10 milliseconds.
-	 *
-	 *  If we receive 10 or more characters,
-	 *  assume its not a human typing, and set RTIME
-	 *  to 100 milliseconds.
-	 */
-
-	if (ch->ch_edelay != DGRP_RTIME) {
-		if (ch->ch_rtime != ch->ch_edelay) {
-			ch->ch_rtime = ch->ch_edelay;
-			ch->ch_flag |= CH_PARAM;
-		}
-	} else if (dlen <= 3) {
-		if (ch->ch_rtime != 10) {
-			ch->ch_rtime = 10;
-			ch->ch_flag |= CH_PARAM;
-		}
-	} else {
-		if (ch->ch_rtime != DGRP_RTIME) {
-			ch->ch_rtime = DGRP_RTIME;
-			ch->ch_flag |= CH_PARAM;
-		}
-	}
-
-	/*
-	 *  If a portion of the packet is outside the
-	 *  buffer, shorten the effective length of the
-	 *  data packet to be the amount of data received.
-	 */
-
-	if (remain < plen)
-		dlen -= plen - remain;
-
-	/*
-	 *  Detect if receive flush is now complete.
-	 */
-
-	if ((ch->ch_flag & CH_RX_FLUSH) != 0 &&
-			((ch->ch_flush_seq - nd->nd_seq_out) & SEQ_MASK) >=
-			((nd->nd_seq_in    - nd->nd_seq_out) & SEQ_MASK)) {
-		ch->ch_flag &= ~CH_RX_FLUSH;
-	}
-
-	/*
-	 *  If we are ready to receive, move the data into
-	 *  the receive buffer.
-	 */
-
-	ch->ch_s_rin = (ch->ch_s_rin + dlen) & 0xffff;
-
-	if (ch->ch_state == CS_READY &&
-			(ch->ch_tun.un_open_count != 0) &&
-			(ch->ch_tun.un_flag & UN_CLOSING) == 0 &&
-			(ch->ch_cflag & CF_CREAD) != 0 &&
-			(ch->ch_flag & (CH_BAUD0 | CH_RX_FLUSH)) == 0 &&
-			(ch->ch_send & RR_RX_FLUSH) == 0) {
-
-		if (ch->ch_rin + dlen >= RBUF_MAX) {
-			n = RBUF_MAX - ch->ch_rin;
-
-			memcpy(ch->ch_rbuf + ch->ch_rin, dbuf, n);
-
-			ch->ch_rin = 0;
-			dbuf += n;
-			dlen -= n;
-		}
-
-		memcpy(ch->ch_rbuf + ch->ch_rin, dbuf, dlen);
-
-		ch->ch_rin += dlen;
-
-
-		/*
-		 *  If we are not in fastcook mode, or
-		 *  if there is a fastcook thread
-		 *  waiting for data, send the data to
-		 *  the line discipline.
-		 */
-
-		if ((ch->ch_flag & CH_FAST_READ) == 0 ||
-				ch->ch_inwait != 0) {
-			dgrp_input(ch);
-		}
-
-		/*
-		 *  If there is a read thread waiting
-		 *  in select, and we are in fastcook
-		 *  mode, wake him up.
-		 */
-
-		if (waitqueue_active(&ch->ch_tun.un_tty->read_wait) &&
-				(ch->ch_flag & CH_FAST_READ) != 0)
-			wake_up_interruptible(&ch->ch_tun.un_tty->read_wait);
-
-		/*
-		 * Wake any thread waiting in the
-		 * fastcook loop.
-		 */
-
-		if ((ch->ch_flag & CH_INPUT) != 0) {
-			ch->ch_flag &= ~CH_INPUT;
-			wake_up_interruptible(&ch->ch_flag_wait);
-		}
-	}
-
-	/*
-	 *  Fabricate and insert a data packet header to
-	 *  preced the remaining data when it comes in.
-	 */
-
-	if (remain < plen) {
-		dlen = plen - remain;
-		b = buf;
-
-		b[0] = 0x90 + n1;
-		put_unaligned_be16(dlen, b + 1);
-
-		remain = 3;
-		if (remain > 0 && b != buf)
-			memcpy(buf, b, remain);
-
-		nd->nd_remain = remain;
-		return;
-	}
-}
-
 /**
  * dgrp_receive() -- decode data packets received from the remote PortServer.
  * @nd: pointer to a node structure
@@ -2477,8 +2306,7 @@ static void dgrp_receive(struct nd_struct *nd)
 			plen = dlen + 1;
 
 			dbuf = b + 1;
-			handle_data_in_packet(nd, ch, dlen, plen, n1, dbuf);
-			break;
+			goto data;
 
 		/*
 		 *  Process 2-byte header data packet.
@@ -2492,8 +2320,7 @@ static void dgrp_receive(struct nd_struct *nd)
 			plen = dlen + 2;
 
 			dbuf = b + 2;
-			handle_data_in_packet(nd, ch, dlen, plen, n1, dbuf);
-			break;
+			goto data;
 
 		/*
 		 *  Process 3-byte header data packet.
@@ -2508,6 +2335,159 @@ static void dgrp_receive(struct nd_struct *nd)
 
 			dbuf = b + 3;
 
+		/*
+		 *  Common packet handling code.
+		 */
+
+data:
+			nd->nd_tx_work = 1;
+
+			/*
+			 *  Otherwise data should appear only when we are
+			 *  in the CS_READY state.
+			 */
+
+			if (ch->ch_state < CS_READY) {
+				error = "Data received before RWIN established";
+				goto prot_error;
+			}
+
+			/*
+			 *  Assure that the data received is within the
+			 *  allowable window.
+			 */
+
+			n = (ch->ch_s_rwin - ch->ch_s_rin) & 0xffff;
+
+			if (dlen > n) {
+				error = "Receive data overrun";
+				goto prot_error;
+			}
+
+			/*
+			 *  If we received 3 or less characters,
+			 *  assume it is a human typing, and set RTIME
+			 *  to 10 milliseconds.
+			 *
+			 *  If we receive 10 or more characters,
+			 *  assume its not a human typing, and set RTIME
+			 *  to 100 milliseconds.
+			 */
+
+			if (ch->ch_edelay != DGRP_RTIME) {
+				if (ch->ch_rtime != ch->ch_edelay) {
+					ch->ch_rtime = ch->ch_edelay;
+					ch->ch_flag |= CH_PARAM;
+				}
+			} else if (dlen <= 3) {
+				if (ch->ch_rtime != 10) {
+					ch->ch_rtime = 10;
+					ch->ch_flag |= CH_PARAM;
+				}
+			} else {
+				if (ch->ch_rtime != DGRP_RTIME) {
+					ch->ch_rtime = DGRP_RTIME;
+					ch->ch_flag |= CH_PARAM;
+				}
+			}
+
+			/*
+			 *  If a portion of the packet is outside the
+			 *  buffer, shorten the effective length of the
+			 *  data packet to be the amount of data received.
+			 */
+
+			if (remain < plen)
+				dlen -= plen - remain;
+
+			/*
+			 *  Detect if receive flush is now complete.
+			 */
+
+			if ((ch->ch_flag & CH_RX_FLUSH) != 0 &&
+			    ((ch->ch_flush_seq - nd->nd_seq_out) & SEQ_MASK) >=
+			    ((nd->nd_seq_in    - nd->nd_seq_out) & SEQ_MASK)) {
+				ch->ch_flag &= ~CH_RX_FLUSH;
+			}
+
+			/*
+			 *  If we are ready to receive, move the data into
+			 *  the receive buffer.
+			 */
+
+			ch->ch_s_rin = (ch->ch_s_rin + dlen) & 0xffff;
+
+			if (ch->ch_state == CS_READY &&
+			    (ch->ch_tun.un_open_count != 0) &&
+			    (ch->ch_tun.un_flag & UN_CLOSING) == 0 &&
+			    (ch->ch_cflag & CF_CREAD) != 0 &&
+			    (ch->ch_flag & (CH_BAUD0 | CH_RX_FLUSH)) == 0 &&
+			    (ch->ch_send & RR_RX_FLUSH) == 0) {
+
+				if (ch->ch_rin + dlen >= RBUF_MAX) {
+					n = RBUF_MAX - ch->ch_rin;
+
+					memcpy(ch->ch_rbuf + ch->ch_rin, dbuf, n);
+
+					ch->ch_rin = 0;
+					dbuf += n;
+					dlen -= n;
+				}
+
+				memcpy(ch->ch_rbuf + ch->ch_rin, dbuf, dlen);
+
+				ch->ch_rin += dlen;
+
+
+				/*
+				 *  If we are not in fastcook mode, or
+				 *  if there is a fastcook thread
+				 *  waiting for data, send the data to
+				 *  the line discipline.
+				 */
+
+				if ((ch->ch_flag & CH_FAST_READ) == 0 ||
+				    ch->ch_inwait != 0) {
+					dgrp_input(ch);
+				}
+
+				/*
+				 *  If there is a read thread waiting
+				 *  in select, and we are in fastcook
+				 *  mode, wake him up.
+				 */
+
+				if (waitqueue_active(&ch->ch_tun.un_tty->read_wait) &&
+				    (ch->ch_flag & CH_FAST_READ) != 0)
+					wake_up_interruptible(&ch->ch_tun.un_tty->read_wait);
+
+				/*
+				 * Wake any thread waiting in the
+				 * fastcook loop.
+				 */
+
+				if ((ch->ch_flag & CH_INPUT) != 0) {
+					ch->ch_flag &= ~CH_INPUT;
+
+					wake_up_interruptible(&ch->ch_flag_wait);
+				}
+			}
+
+			/*
+			 *  Fabricate and insert a data packet header to
+			 *  preced the remaining data when it comes in.
+			 */
+
+			if (remain < plen) {
+				dlen = plen - remain;
+				b = buf;
+
+				b[0] = 0x90 + n1;
+				put_unaligned_be16(dlen, b + 1);
+
+				remain = 3;
+				goto done;
+			}
 			break;
 
 		/*