Date: Fri, 16 Apr 2021 19:25:59 GMT From: Richard Scheffenegger <rscheff@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: f1650b162d26 - stable/13 - Make sbuf_drain safe for external use Message-ID: <202104161925.13GJPxkA060282@gitrepo.freebsd.org>
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The branch stable/13 has been updated by rscheff: URL: https://cgit.FreeBSD.org/src/commit/?id=f1650b162d26b91b6b170f10250f46617a0bcedc commit f1650b162d26b91b6b170f10250f46617a0bcedc Author: Richard Scheffenegger <rscheff@FreeBSD.org> AuthorDate: 2021-04-02 18:11:45 +0000 Commit: Richard Scheffenegger <rscheff@FreeBSD.org> CommitDate: 2021-04-16 18:51:20 +0000 Make sbuf_drain safe for external use While sbuf_drain was an internal function, two KASSERTS checked the sanity of it being called. However, an external caller may be ignorant if there is any data to drain, or if an error has already accumulated. Be nice and return immediately with the accumulated error. MFC after: 2 weeks Reviewed By: tuexen, #transport Sponsored by: NetApp, Inc. Differential Revision: https://reviews.freebsd.org/D29544 (cherry picked from commit cad4fd0365a5e3235e715e072e6ee9dffaa7a3ab) --- sys/kern/subr_sbuf.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/sys/kern/subr_sbuf.c b/sys/kern/subr_sbuf.c index 66822115dbcb..cdeaf690208f 100644 --- a/sys/kern/subr_sbuf.c +++ b/sys/kern/subr_sbuf.c @@ -388,8 +388,12 @@ sbuf_drain(struct sbuf *s) { int len; - KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s)); - KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s)); + /* + * Immediately return when no work to do, + * or an error has already been accumulated. + */ + if ((s->s_len == 0) || (s->s_error != 0)) + return(s->s_error); if (SBUF_DODRAINTOEOR(s) && s->s_rec_off == 0) return (s->s_error = EDEADLK);
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