WARNING: externs should be avoided in .c files
#52: FILE: kernel/bpf/crib/bpf_checkpoint.c:17:
+extern struct sk_buff *bpf_skb_acquire(struct sk_buff *skb);

WARNING: externs should be avoided in .c files
#54: FILE: kernel/bpf/crib/bpf_checkpoint.c:19:
+extern void bpf_skb_release(struct sk_buff *skb);

CHECK: Alignment should match open parenthesis
#72: FILE: kernel/bpf/crib/bpf_checkpoint.c:178:
+__bpf_kfunc int bpf_iter_skb_new(struct bpf_iter_skb *it,
+		struct sk_buff_head *head)

WARNING: line length of 86 exceeds 80 columns
#76: FILE: kernel/bpf/crib/bpf_checkpoint.c:182:
+	BUILD_BUG_ON(sizeof(struct bpf_iter_skb_kern) != sizeof(struct bpf_iter_skb));

WARNING: line length of 96 exceeds 80 columns
#77: FILE: kernel/bpf/crib/bpf_checkpoint.c:183:
+	BUILD_BUG_ON(__alignof__(struct bpf_iter_skb_kern) != __alignof__(struct bpf_iter_skb));

total: 0 errors, 4 warnings, 1 checks, 112 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 27db20c54fa0 ("bpf/crib: Introduce skb open-coded iterator kfuncs") 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, 112 lines checked