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Commit dfa7d920 authored by David Howells's avatar David Howells
Browse files

rxrpc: Fix retransmission algorithm 



Make the retransmission algorithm use for-loops instead of do-loops and
move the counter increments into the for-statement increment slots.

Though the do-loops are slighly more efficient since there will be at least
one pass through the each loop, the counter increments are harder to get
right as the continue-statements skip them.

Without this, if there are any positive acks within the loop, the do-loop
will cycle forever because the counter increment is never done.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent d01dc4c3

net/rxrpc/call_event.c

+4 −8
Original line number Diff line number Diff line
@@ -163,8 +163,7 @@ static void rxrpc_resend(struct rxrpc_call *call) 
	 */

	now = jiffies;

	resend_at = now + rxrpc_resend_timeout;

	seq = cursor + 1;

	do {

	for (seq = cursor + 1; before_eq(seq, top); seq++) {

		ix = seq & RXRPC_RXTX_BUFF_MASK;

		annotation = call->rxtx_annotations[ix];

		if (annotation == RXRPC_TX_ANNO_ACK)
@@ -184,8 +183,7 @@ static void rxrpc_resend(struct rxrpc_call *call) 


		/* Okay, we need to retransmit a packet. */

		call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;

		seq++;

	} while (before_eq(seq, top));

	}



	call->resend_at = resend_at;
@@ -194,8 +192,7 @@ static void rxrpc_resend(struct rxrpc_call *call) 
	 * lock is dropped, it may clear some of the retransmission markers for

	 * packets that it soft-ACKs.

	 */

	seq = cursor + 1;

	do {

	for (seq = cursor + 1; before_eq(seq, top); seq++) {

		ix = seq & RXRPC_RXTX_BUFF_MASK;

		annotation = call->rxtx_annotations[ix];

		if (annotation != RXRPC_TX_ANNO_RETRANS)
@@ -237,8 +234,7 @@ static void rxrpc_resend(struct rxrpc_call *call) 


		if (after(call->tx_hard_ack, seq))

			seq = call->tx_hard_ack;

		seq++;

	} while (before_eq(seq, top));

	}



out_unlock:

	spin_unlock_bh(&call->lock);