MINOR: quic: simplify qc_prep_pkts() exit path

To prepare pacing support, qc_prep_pkts() exit path have been rewritten
to be easily modified. This is purely refactoring which should not have
any functional change :
* a dedicated error path has been added
* ensure qc_txb_store() is always called to finalize datagram on normal
  exit path if first_pkt is not NULL. Needed to support breaking from
  packet building loop in a easier way.

diff --git a/src/quic_tx.c b/src/quic_tx.c
index fc89ca66b99f201cffc90be9aaee5d81325543ea..fbcbcaf4a92d7d92dcdd785a0b59ed64d3cdd0bc 100644 (file)
--- a/src/quic_tx.c
+++ b/src/quic_tx.c
@@ -533,12 +533,12 @@ static inline void qc_select_tls_ver(struct quic_conn *qc,
 static int qc_prep_pkts(struct quic_conn *qc, struct buffer *buf,
                          struct list *qels)
 {
-       int ret, cc, padding;
+       int cc, padding;
        struct quic_tx_packet *first_pkt, *prv_pkt;
        unsigned char *end, *pos;
        uint32_t wrlen; /* may differ from dglen if GSO used */
        uint16_t dglen;
-       size_t total;
+       int total = 0;
        struct quic_enc_level *qel, *tmp_qel;
        uchar gso_dgram_cnt = 0;
 
@@ -548,13 +548,11 @@ static int qc_prep_pkts(struct quic_conn *qc, struct buffer *buf,
         */
        BUG_ON_HOT(buf->head || buf->data);
 
-       ret = -1;
        cc =  qc->flags & QUIC_FL_CONN_IMMEDIATE_CLOSE;
        padding = 0;
        first_pkt = prv_pkt = NULL;
        end = pos = (unsigned char *)b_head(buf);
        dglen = wrlen = 0;
-       total = 0;
 
        list_for_each_entry_safe(qel, tmp_qel, qels, el_send) {
                struct quic_tls_ctx *tls_ctx;
@@ -668,7 +666,8 @@ static int qc_prep_pkts(struct quic_conn *qc, struct buffer *buf,
                                }
 
                                if (err == QC_BUILD_PKT_ERR_ALLOC || err == QC_BUILD_PKT_ERR_ENCRYPT)
-                                       goto leave;
+                                       goto err;
+                               first_pkt = NULL;
                                goto out;
                        }
 
@@ -703,10 +702,8 @@ static int qc_prep_pkts(struct quic_conn *qc, struct buffer *buf,
                        BUG_ON(padding && !next_qel);
 
                        /* Build only one datagram when an immediate close is required. */
-                       if (cc) {
-                               qc_txb_store(buf, dglen, first_pkt);
+                       if (cc)
                                goto out;
-                       }
 
                        /* Only one short packet by datagram when probing. */
                        if (probe && qel == qc->ael)
@@ -753,20 +750,22 @@ static int qc_prep_pkts(struct quic_conn *qc, struct buffer *buf,
                TRACE_DEVEL("next encryption level", QUIC_EV_CONN_PHPKTS, qc);
        }
 
+ out:
        if (first_pkt)
                qc_txb_store(buf, wrlen, first_pkt);
 
- out:
        if (cc && total) {
                BUG_ON(buf != &qc->tx.cc_buf);
                BUG_ON(dglen != total);
                qc->tx.cc_dgram_len = dglen;
        }
 
-       ret = total;
- leave:
        TRACE_LEAVE(QUIC_EV_CONN_PHPKTS, qc);
-       return ret;
+       return total;
+
+ err:
+       TRACE_DEVEL("leaving on error", QUIC_EV_CONN_PHPKTS, qc);
+       return -1;
 }
 
 /* Encode frames and send them as packets for <qc> connection. Input frames are