WARNING: suspect code indent for conditional statements (8, 12)
#69: FILE: include/net/tcp.h:1424:
+	if (event == CA_EVENT_TX_START) {
+	    if (icsk->icsk_ca_ops->cwnd_event_tx_start)

WARNING: Statements should start on a tabstop
#70: FILE: include/net/tcp.h:1425:
+	    if (icsk->icsk_ca_ops->cwnd_event_tx_start)

WARNING: suspect code indent for conditional statements (12, 24)
#70: FILE: include/net/tcp.h:1425:
+	    if (icsk->icsk_ca_ops->cwnd_event_tx_start)
+			icsk->icsk_ca_ops->cwnd_event_tx_start(sk);

WARNING: line length of 81 exceeds 80 columns
#196: FILE: net/ipv4/tcp_dctcp.c:216:
+	tcp_plb_check_rehash(sk, &ca->plb); /* Maybe rehash when inflight is 0 */

total: 0 errors, 4 warnings, 0 checks, 301 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

Commit 76861c321bdd ("tcp: add cwnd_event_tx_start to tcp_congestion_ops") has style problems, please review.

NOTE: Ignored message types: ALLOC_SIZEOF_STRUCT BAD_REPORTED_BY_LINK CAMELCASE COMMIT_LOG_LONG_LINE FILE_PATH_CHANGES GIT_COMMIT_ID MACRO_ARG_REUSE NO_AUTHOR_SIGN_OFF

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.
total: 0 errors, 4 warnings, 0 checks, 301 lines checked