Date: Fri, 16 Apr 2021 19:36:20 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: 424f6363927a - stable/12 - Make sbuf_drain safe for external use Message-ID: <202104161936.13GJaK8M073818@gitrepo.freebsd.org>
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The branch stable/12 has been updated by rscheff: URL: https://cgit.FreeBSD.org/src/commit/?id=424f6363927a113fe5a1dcb4691039ec25cf3680 commit 424f6363927a113fe5a1dcb4691039ec25cf3680 Author: Richard Scheffenegger <rscheff@FreeBSD.org> AuthorDate: 2021-04-02 18:11:45 +0000 Commit: Richard Scheffenegger <rscheff@FreeBSD.org> CommitDate: 2021-04-16 19:34:26 +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 | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/sys/kern/subr_sbuf.c b/sys/kern/subr_sbuf.c index c8f2af2ebca2..ac6bc14b7a8c 100644 --- a/sys/kern/subr_sbuf.c +++ b/sys/kern/subr_sbuf.c @@ -380,8 +380,13 @@ 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); len = s->s_drain_func(s->s_drain_arg, s->s_buf,
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