From owner-svn-src-all@FreeBSD.ORG Mon Oct 27 20:20:06 2014 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id BB13E36D; Mon, 27 Oct 2014 20:20:06 +0000 (UTC) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id A7D91D8F; Mon, 27 Oct 2014 20:20:06 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.9/8.14.9) with ESMTP id s9RKK6Ww065967; Mon, 27 Oct 2014 20:20:06 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by svn.freebsd.org (8.14.9/8.14.9/Submit) id s9RKK6ln065966; Mon, 27 Oct 2014 20:20:06 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <201410272020.s9RKK6ln065966@svn.freebsd.org> X-Authentication-Warning: svn.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Mon, 27 Oct 2014 20:20:06 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r273746 - head/sys/kern X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Oct 2014 20:20:06 -0000 Author: mjg Date: Mon Oct 27 20:20:05 2014 New Revision: 273746 URL: https://svnweb.freebsd.org/changeset/base/273746 Log: Tidy up functions related to uidinfo management. - reference found uidinfo in uilookup - reduce nesting by handling shorter cases first Modified: head/sys/kern/kern_resource.c Modified: head/sys/kern/kern_resource.c ============================================================================== --- head/sys/kern/kern_resource.c Mon Oct 27 20:18:30 2014 (r273745) +++ head/sys/kern/kern_resource.c Mon Oct 27 20:20:05 2014 (r273746) @@ -1215,6 +1215,7 @@ uihashinit() /* * Look up a uidinfo struct for the parameter uid. * uihashtbl_lock must be locked. + * Increase refcount on uidinfo struct returned. */ static struct uidinfo * uilookup(uid_t uid) @@ -1225,49 +1226,52 @@ uilookup(uid_t uid) rw_assert(&uihashtbl_lock, RA_LOCKED); uipp = UIHASH(uid); LIST_FOREACH(uip, uipp, ui_hash) - if (uip->ui_uid == uid) + if (uip->ui_uid == uid) { + uihold(uip); break; + } return (uip); } /* * Find or allocate a struct uidinfo for a particular uid. - * Increase refcount on uidinfo struct returned. + * Returns with uidinfo struct referenced. * uifree() should be called on a struct uidinfo when released. */ struct uidinfo * uifind(uid_t uid) { - struct uidinfo *old_uip, *uip; + struct uidinfo *new_uip, *uip; rw_rlock(&uihashtbl_lock); uip = uilookup(uid); - if (uip == NULL) { - rw_runlock(&uihashtbl_lock); - uip = malloc(sizeof(*uip), M_UIDINFO, M_WAITOK | M_ZERO); - racct_create(&uip->ui_racct); - rw_wlock(&uihashtbl_lock); - /* - * There's a chance someone created our uidinfo while we - * were in malloc and not holding the lock, so we have to - * make sure we don't insert a duplicate uidinfo. - */ - if ((old_uip = uilookup(uid)) != NULL) { - /* Someone else beat us to it. */ - racct_destroy(&uip->ui_racct); - free(uip, M_UIDINFO); - uip = old_uip; - } else { - refcount_init(&uip->ui_ref, 0); - uip->ui_uid = uid; - mtx_init(&uip->ui_vmsize_mtx, "ui_vmsize", NULL, - MTX_DEF); - LIST_INSERT_HEAD(UIHASH(uid), uip, ui_hash); - } + rw_runlock(&uihashtbl_lock); + if (uip != NULL) + return (uip); + + new_uip = malloc(sizeof(*new_uip), M_UIDINFO, M_WAITOK | M_ZERO); + racct_create(&new_uip->ui_racct); + refcount_init(&new_uip->ui_ref, 1); + new_uip->ui_uid = uid; + mtx_init(&new_uip->ui_vmsize_mtx, "ui_vmsize", NULL, MTX_DEF); + + rw_wlock(&uihashtbl_lock); + /* + * There's a chance someone created our uidinfo while we + * were in malloc and not holding the lock, so we have to + * make sure we don't insert a duplicate uidinfo. + */ + if ((uip = uilookup(uid)) == NULL) { + LIST_INSERT_HEAD(UIHASH(uid), new_uip, ui_hash); + rw_wunlock(&uihashtbl_lock); + uip = new_uip; + } else { + rw_wunlock(&uihashtbl_lock); + racct_destroy(&new_uip->ui_racct); + mtx_destroy(&new_uip->ui_vmsize_mtx); + free(new_uip, M_UIDINFO); } - uihold(uip); - rw_unlock(&uihashtbl_lock); return (uip); } @@ -1308,28 +1312,26 @@ uifree(struct uidinfo *uip) /* Prepare for suboptimal case. */ rw_wlock(&uihashtbl_lock); - if (refcount_release(&uip->ui_ref)) { - racct_destroy(&uip->ui_racct); - LIST_REMOVE(uip, ui_hash); + if (refcount_release(&uip->ui_ref) == 0) { rw_wunlock(&uihashtbl_lock); - if (uip->ui_sbsize != 0) - printf("freeing uidinfo: uid = %d, sbsize = %ld\n", - uip->ui_uid, uip->ui_sbsize); - if (uip->ui_proccnt != 0) - printf("freeing uidinfo: uid = %d, proccnt = %ld\n", - uip->ui_uid, uip->ui_proccnt); - if (uip->ui_vmsize != 0) - printf("freeing uidinfo: uid = %d, swapuse = %lld\n", - uip->ui_uid, (unsigned long long)uip->ui_vmsize); - mtx_destroy(&uip->ui_vmsize_mtx); - free(uip, M_UIDINFO); return; } - /* - * Someone added a reference between atomic_cmpset_int() and - * rw_wlock(&uihashtbl_lock). - */ + + racct_destroy(&uip->ui_racct); + LIST_REMOVE(uip, ui_hash); rw_wunlock(&uihashtbl_lock); + + if (uip->ui_sbsize != 0) + printf("freeing uidinfo: uid = %d, sbsize = %ld\n", + uip->ui_uid, uip->ui_sbsize); + if (uip->ui_proccnt != 0) + printf("freeing uidinfo: uid = %d, proccnt = %ld\n", + uip->ui_uid, uip->ui_proccnt); + if (uip->ui_vmsize != 0) + printf("freeing uidinfo: uid = %d, swapuse = %lld\n", + uip->ui_uid, (unsigned long long)uip->ui_vmsize); + mtx_destroy(&uip->ui_vmsize_mtx); + free(uip, M_UIDINFO); } void