WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
#69: FILE: include/net/tcp.h:147:
+#define TCP_RTO_MAX	((unsigned)(TCP_RTO_MAX_SEC * HZ))

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
#70: FILE: include/net/tcp.h:148:
+#define TCP_RTO_MIN	((unsigned)(HZ / 5))

WARNING: line length of 81 exceeds 80 columns
#207: FILE: net/ipv4/tcp_timer.c:112:
+	if ((s32)(tcp_jiffies32 - tp->lsndtime) > 2*tcp_rto_max(sk) || !do_reset)

CHECK: spaces preferred around that '*' (ctx:VxV)
#207: FILE: net/ipv4/tcp_timer.c:112:
+	if ((s32)(tcp_jiffies32 - tp->lsndtime) > 2*tcp_rto_max(sk) || !do_reset)
 	                                           ^

WARNING: line length of 81 exceeds 80 columns
#241: FILE: net/ipv4/tcp_timer.c:420:
+		const bool alive = inet_csk_rto_backoff(icsk, rto_max) < rto_max;

total: 0 errors, 4 warnings, 1 checks, 182 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 b2bdba2c9d4f ("tcp: add the ability to control max RTO") has style problems, please review.

NOTE: Ignored message types: ALLOC_SIZEOF_STRUCT BAD_REPORTED_BY_LINK CAMELCASE COMMIT_LOG_LONG_LINE 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, 1 checks, 182 lines checked