Date: Tue, 1 Sep 2015 13:21:33 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r287362 - head/sys/kern Message-ID: <201509011321.t81DLXoD008780@repo.freebsd.org>
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Author: kib Date: Tue Sep 1 13:21:32 2015 New Revision: 287362 URL: https://svnweb.freebsd.org/changeset/base/287362 Log: Clean up the kqueue use of the uma KPI. Explain why it is fine to not check for M_NOWAIT failures in kqueue_register(). Remove unneeded check for NULL result from waitable allocation in kqueue_scan(). uma_free(9) handles NULL argument correctly, remove checks for NULL. Remove useless cast and adjust style in knote_alloc(). Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Modified: head/sys/kern/kern_event.c Modified: head/sys/kern/kern_event.c ============================================================================== --- head/sys/kern/kern_event.c Tue Sep 1 13:07:27 2015 (r287361) +++ head/sys/kern/kern_event.c Tue Sep 1 13:21:32 2015 (r287362) @@ -1105,10 +1105,16 @@ kqueue_register(struct kqueue *kq, struc if (fops == NULL) return EINVAL; - if (kev->flags & EV_ADD) - tkn = knote_alloc(waitok); /* prevent waiting with locks */ - else + if (kev->flags & EV_ADD) { + /* + * Prevent waiting with locks. Non-sleepable + * allocation failures are handled in the loop, only + * if the spare knote appears to be actually required. + */ + tkn = knote_alloc(waitok); + } else { tkn = NULL; + } findkn: if (fops->f_isfd) { @@ -1310,8 +1316,7 @@ done: FILEDESC_XUNLOCK(td->td_proc->p_fd); if (fp != NULL) fdrop(fp, td); - if (tkn != NULL) - knote_free(tkn); + knote_free(tkn); if (fops != NULL) kqueue_fo_release(filt); return (error); @@ -1507,10 +1512,6 @@ kqueue_scan(struct kqueue *kq, int maxev } else asbt = 0; marker = knote_alloc(1); - if (marker == NULL) { - error = ENOMEM; - goto done_nl; - } marker->kn_status = KN_MARKER; KQ_LOCK(kq); @@ -2385,15 +2386,16 @@ SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_A static struct knote * knote_alloc(int waitok) { - return ((struct knote *)uma_zalloc(knote_zone, - (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); + + return (uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT) | + M_ZERO)); } static void knote_free(struct knote *kn) { - if (kn != NULL) - uma_zfree(knote_zone, kn); + + uma_zfree(knote_zone, kn); } /*
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