From: Ilpo Järvinen Date: Sat, 6 Dec 2008 06:42:22 +0000 (-0800) Subject: tcp: introduce struct tcp_sacktag_state to reduce arg pressure X-Git-Tag: v2.6.29-rc1~581^2~298 X-Git-Url: http://bbs.cooldavid.org/git/?a=commitdiff_plain;h=a1197f5a6faa23e5d0c1f8ed97b011deb2a75457;p=net-next-2.6.git tcp: introduce struct tcp_sacktag_state to reduce arg pressure There are just too many args to some sacktag functions. This idea was first proposed by David S. Miller around a year ago, and the current situation is much worse that what it was back then. tcp_sacktag_one can be made a bit simpler by returning the new sacked (it can be achieved with a single variable though the previous code "caching" sacked into a local variable and therefore it is not exactly equal but the results will be the same). codiff on x86_64 tcp_sacktag_one | -15 tcp_shifted_skb | -50 tcp_match_skb_to_sack | -1 tcp_sacktag_walk | -64 tcp_sacktag_write_queue | -59 tcp_urg | +1 tcp_event_data_recv | -1 7 functions changed, 1 bytes added, 190 bytes removed, diff: -189 Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 21c67019078..e25827719e7 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1237,6 +1237,12 @@ static int tcp_check_dsack(struct sock *sk, struct sk_buff *ack_skb, return dup_sack; } +struct tcp_sacktag_state { + int reord; + int fack_count; + int flag; +}; + /* Check if skb is fully within the SACK block. In presence of GSO skbs, * the incoming SACK may not exactly match but we can find smaller MSS * aligned portion of it that matches. Therefore we might need to fragment @@ -1290,25 +1296,25 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb, return in_sack; } -static int tcp_sacktag_one(struct sk_buff *skb, struct sock *sk, - int *reord, int dup_sack, int fack_count, - u8 *sackedto, int pcount) +static u8 tcp_sacktag_one(struct sk_buff *skb, struct sock *sk, + struct tcp_sacktag_state *state, + int dup_sack, int pcount) { struct tcp_sock *tp = tcp_sk(sk); u8 sacked = TCP_SKB_CB(skb)->sacked; - int flag = 0; + int fack_count = state->fack_count; /* Account D-SACK for retransmitted packet. */ if (dup_sack && (sacked & TCPCB_RETRANS)) { if (after(TCP_SKB_CB(skb)->end_seq, tp->undo_marker)) tp->undo_retrans--; if (sacked & TCPCB_SACKED_ACKED) - *reord = min(fack_count, *reord); + state->reord = min(fack_count, state->reord); } /* Nothing to do; acked frame is about to be dropped (was ACKed). */ if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una)) - return flag; + return sacked; if (!(sacked & TCPCB_SACKED_ACKED)) { if (sacked & TCPCB_SACKED_RETRANS) { @@ -1317,7 +1323,7 @@ static int tcp_sacktag_one(struct sk_buff *skb, struct sock *sk, * that retransmission is still in flight. */ if (sacked & TCPCB_LOST) { - *sackedto &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS); + sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS); tp->lost_out -= pcount; tp->retrans_out -= pcount; } @@ -1328,21 +1334,22 @@ static int tcp_sacktag_one(struct sk_buff *skb, struct sock *sk, */ if (before(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp))) - *reord = min(fack_count, *reord); + state->reord = min(fack_count, + state->reord); /* SACK enhanced F-RTO (RFC4138; Appendix B) */ if (!after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark)) - flag |= FLAG_ONLY_ORIG_SACKED; + state->flag |= FLAG_ONLY_ORIG_SACKED; } if (sacked & TCPCB_LOST) { - *sackedto &= ~TCPCB_LOST; + sacked &= ~TCPCB_LOST; tp->lost_out -= pcount; } } - *sackedto |= TCPCB_SACKED_ACKED; - flag |= FLAG_DATA_SACKED; + sacked |= TCPCB_SACKED_ACKED; + state->flag |= FLAG_DATA_SACKED; tp->sacked_out += pcount; fack_count += pcount; @@ -1361,21 +1368,20 @@ static int tcp_sacktag_one(struct sk_buff *skb, struct sock *sk, * frames and clear it. undo_retrans is decreased above, L|R frames * are accounted above as well. */ - if (dup_sack && (*sackedto & TCPCB_SACKED_RETRANS)) { - *sackedto &= ~TCPCB_SACKED_RETRANS; + if (dup_sack && (sacked & TCPCB_SACKED_RETRANS)) { + sacked &= ~TCPCB_SACKED_RETRANS; tp->retrans_out -= pcount; } - return flag; + return sacked; } static int tcp_shifted_skb(struct sock *sk, struct sk_buff *prev, - struct sk_buff *skb, unsigned int pcount, - int shifted, int fack_count, int *reord, - int *flag, int mss) + struct sk_buff *skb, + struct tcp_sacktag_state *state, + unsigned int pcount, int shifted, int mss) { struct tcp_sock *tp = tcp_sk(sk); - u8 dummy_sacked = TCP_SKB_CB(skb)->sacked; /* We discard results */ BUG_ON(!pcount); @@ -1407,8 +1413,8 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *prev, skb_shinfo(skb)->gso_type = 0; } - *flag |= tcp_sacktag_one(skb, sk, reord, 0, fack_count, &dummy_sacked, - pcount); + /* We discard results */ + tcp_sacktag_one(skb, sk, state, 0, pcount); /* Difference in this won't matter, both ACKed by the same cumul. ACK */ TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS); @@ -1460,9 +1466,9 @@ static int skb_can_shift(struct sk_buff *skb) * skb. */ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb, + struct tcp_sacktag_state *state, u32 start_seq, u32 end_seq, - int dup_sack, int *fack_count, - int *reord, int *flag) + int dup_sack) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *prev; @@ -1559,8 +1565,7 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb, if (!skb_shift(prev, skb, len)) goto fallback; - if (!tcp_shifted_skb(sk, prev, skb, pcount, len, *fack_count, reord, - flag, mss)) + if (!tcp_shifted_skb(sk, prev, skb, state, pcount, len, mss)) goto out; /* Hole filled allows collapsing with the next as well, this is very @@ -1579,12 +1584,12 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb, len = skb->len; if (skb_shift(prev, skb, len)) { pcount += tcp_skb_pcount(skb); - tcp_shifted_skb(sk, prev, skb, tcp_skb_pcount(skb), len, - *fack_count, reord, flag, mss); + tcp_shifted_skb(sk, prev, skb, state, tcp_skb_pcount(skb), len, + mss); } out: - *fack_count += pcount; + state->fack_count += pcount; return prev; noop: @@ -1597,9 +1602,9 @@ fallback: static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk, struct tcp_sack_block *next_dup, + struct tcp_sacktag_state *state, u32 start_seq, u32 end_seq, - int dup_sack_in, int *fack_count, - int *reord, int *flag) + int dup_sack_in) { struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *tmp; @@ -1629,9 +1634,8 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk, * so not even _safe variant of the loop is enough. */ if (in_sack <= 0) { - tmp = tcp_shift_skb_data(sk, skb, start_seq, - end_seq, dup_sack, - fack_count, reord, flag); + tmp = tcp_shift_skb_data(sk, skb, state, + start_seq, end_seq, dup_sack); if (tmp != NULL) { if (tmp != skb) { skb = tmp; @@ -1650,17 +1654,17 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk, break; if (in_sack) { - *flag |= tcp_sacktag_one(skb, sk, reord, dup_sack, - *fack_count, - &(TCP_SKB_CB(skb)->sacked), - tcp_skb_pcount(skb)); + TCP_SKB_CB(skb)->sacked = tcp_sacktag_one(skb, sk, + state, + dup_sack, + tcp_skb_pcount(skb)); if (!before(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp))) tcp_advance_highest_sack(sk, skb); } - *fack_count += tcp_skb_pcount(skb); + state->fack_count += tcp_skb_pcount(skb); } return skb; } @@ -1669,7 +1673,8 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk, * a normal way */ static struct sk_buff *tcp_sacktag_skip(struct sk_buff *skb, struct sock *sk, - u32 skip_to_seq, int *fack_count) + struct tcp_sacktag_state *state, + u32 skip_to_seq) { tcp_for_write_queue_from(skb, sk) { if (skb == tcp_send_head(sk)) @@ -1678,7 +1683,7 @@ static struct sk_buff *tcp_sacktag_skip(struct sk_buff *skb, struct sock *sk, if (after(TCP_SKB_CB(skb)->end_seq, skip_to_seq)) break; - *fack_count += tcp_skb_pcount(skb); + state->fack_count += tcp_skb_pcount(skb); } return skb; } @@ -1686,18 +1691,17 @@ static struct sk_buff *tcp_sacktag_skip(struct sk_buff *skb, struct sock *sk, static struct sk_buff *tcp_maybe_skipping_dsack(struct sk_buff *skb, struct sock *sk, struct tcp_sack_block *next_dup, - u32 skip_to_seq, - int *fack_count, int *reord, - int *flag) + struct tcp_sacktag_state *state, + u32 skip_to_seq) { if (next_dup == NULL) return skb; if (before(next_dup->start_seq, skip_to_seq)) { - skb = tcp_sacktag_skip(skb, sk, next_dup->start_seq, fack_count); - skb = tcp_sacktag_walk(skb, sk, NULL, - next_dup->start_seq, next_dup->end_seq, - 1, fack_count, reord, flag); + skb = tcp_sacktag_skip(skb, sk, state, next_dup->start_seq); + skb = tcp_sacktag_walk(skb, sk, NULL, state, + next_dup->start_seq, next_dup->end_seq, + 1); } return skb; @@ -1719,16 +1723,17 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, struct tcp_sack_block_wire *sp_wire = (struct tcp_sack_block_wire *)(ptr+2); struct tcp_sack_block sp[TCP_NUM_SACKS]; struct tcp_sack_block *cache; + struct tcp_sacktag_state state; struct sk_buff *skb; int num_sacks = min(TCP_NUM_SACKS, (ptr[1] - TCPOLEN_SACK_BASE) >> 3); int used_sacks; - int reord = tp->packets_out; - int flag = 0; int found_dup_sack = 0; - int fack_count; int i, j; int first_sack_index; + state.flag = 0; + state.reord = tp->packets_out; + if (!tp->sacked_out) { if (WARN_ON(tp->fackets_out)) tp->fackets_out = 0; @@ -1738,7 +1743,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, found_dup_sack = tcp_check_dsack(sk, ack_skb, sp_wire, num_sacks, prior_snd_una); if (found_dup_sack) - flag |= FLAG_DSACKING_ACK; + state.flag |= FLAG_DSACKING_ACK; /* Eliminate too old ACKs, but take into * account more or less fresh ones, they can @@ -1807,7 +1812,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, } skb = tcp_write_queue_head(sk); - fack_count = 0; + state.fack_count = 0; i = 0; if (!tp->sacked_out) { @@ -1832,7 +1837,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, /* Event "B" in the comment above. */ if (after(end_seq, tp->high_seq)) - flag |= FLAG_DATA_LOST; + state.flag |= FLAG_DATA_LOST; /* Skip too early cached blocks */ while (tcp_sack_cache_ok(tp, cache) && @@ -1845,13 +1850,13 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, /* Head todo? */ if (before(start_seq, cache->start_seq)) { - skb = tcp_sacktag_skip(skb, sk, start_seq, - &fack_count); + skb = tcp_sacktag_skip(skb, sk, &state, + start_seq); skb = tcp_sacktag_walk(skb, sk, next_dup, + &state, start_seq, cache->start_seq, - dup_sack, &fack_count, - &reord, &flag); + dup_sack); } /* Rest of the block already fully processed? */ @@ -1859,9 +1864,8 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, goto advance_sp; skb = tcp_maybe_skipping_dsack(skb, sk, next_dup, - cache->end_seq, - &fack_count, &reord, - &flag); + &state, + cache->end_seq); /* ...tail remains todo... */ if (tcp_highest_sack_seq(tp) == cache->end_seq) { @@ -1869,13 +1873,12 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, skb = tcp_highest_sack(sk); if (skb == NULL) break; - fack_count = tp->fackets_out; + state.fack_count = tp->fackets_out; cache++; goto walk; } - skb = tcp_sacktag_skip(skb, sk, cache->end_seq, - &fack_count); + skb = tcp_sacktag_skip(skb, sk, &state, cache->end_seq); /* Check overlap against next cached too (past this one already) */ cache++; continue; @@ -1885,20 +1888,20 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, skb = tcp_highest_sack(sk); if (skb == NULL) break; - fack_count = tp->fackets_out; + state.fack_count = tp->fackets_out; } - skb = tcp_sacktag_skip(skb, sk, start_seq, &fack_count); + skb = tcp_sacktag_skip(skb, sk, &state, start_seq); walk: - skb = tcp_sacktag_walk(skb, sk, next_dup, start_seq, end_seq, - dup_sack, &fack_count, &reord, &flag); + skb = tcp_sacktag_walk(skb, sk, next_dup, &state, + start_seq, end_seq, dup_sack); advance_sp: /* SACK enhanced FRTO (RFC4138, Appendix B): Clearing correct * due to in-order walk */ if (after(end_seq, tp->frto_highmark)) - flag &= ~FLAG_ONLY_ORIG_SACKED; + state.flag &= ~FLAG_ONLY_ORIG_SACKED; i++; } @@ -1915,10 +1918,10 @@ advance_sp: tcp_verify_left_out(tp); - if ((reord < tp->fackets_out) && + if ((state.reord < tp->fackets_out) && ((icsk->icsk_ca_state != TCP_CA_Loss) || tp->undo_marker) && (!tp->frto_highmark || after(tp->snd_una, tp->frto_highmark))) - tcp_update_reordering(sk, tp->fackets_out - reord, 0); + tcp_update_reordering(sk, tp->fackets_out - state.reord, 0); out: @@ -1928,7 +1931,7 @@ out: WARN_ON((int)tp->retrans_out < 0); WARN_ON((int)tcp_packets_in_flight(tp) < 0); #endif - return flag; + return state.flag; } /* Limits sacked_out so that sum with lost_out isn't ever larger than