WARNING: line length of 89 exceeds 80 columns
#35: FILE: include/linux/perf_event.h:1726:
+extern int __get_perf_callchain(struct perf_callchain_entry *entry, struct pt_regs *regs,

CHECK: extern prototypes should be avoided in .h files
#35: FILE: include/linux/perf_event.h:1726:
+extern int __get_perf_callchain(struct perf_callchain_entry *entry, struct pt_regs *regs,

WARNING: line length of 101 exceeds 80 columns
#36: FILE: include/linux/perf_event.h:1727:
+				bool kernel, bool user, u32 max_stack, bool crosstask, bool add_mark,

WARNING: line length of 95 exceeds 80 columns
#53: FILE: kernel/events/callchain.c:224:
+int __get_perf_callchain(struct perf_callchain_entry *entry, struct pt_regs *regs, bool kernel,

WARNING: line length of 99 exceeds 80 columns
#54: FILE: kernel/events/callchain.c:225:
+			 bool user, u32 max_stack, bool crosstask, bool add_mark, u64 defer_cookie)

WARNING: line length of 82 exceeds 80 columns
#98: FILE: kernel/events/callchain.c:277:
+		   u32 max_stack, bool crosstask, bool add_mark, u64 defer_cookie)

WARNING: line length of 93 exceeds 80 columns
#108: FILE: kernel/events/callchain.c:286:
+	ret = __get_perf_callchain(entry, regs, kernel, user, max_stack, crosstask, add_mark,

total: 0 errors, 6 warnings, 1 checks, 77 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 256acd1fe782 ("perf: Refactor get_perf_callchain") 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, 6 warnings, 1 checks, 77 lines checked