Date: Sun, 17 Aug 2014 06:52:35 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r270084 - stable/10/sys/kern Message-ID: <201408170652.s7H6qZeH028464@svn.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: mjg Date: Sun Aug 17 06:52:35 2014 New Revision: 270084 URL: http://svnweb.freebsd.org/changeset/base/270084 Log: MFC r268074: Perform a lockless check in sigacts_shared. It is used only during execve (i.e. singlethreaded), so there is no fear of returning 'not shared' which soon becomes 'shared'. While here reorganize the code a little to avoid proc lock/unlock in shared case. Modified: stable/10/sys/kern/kern_exec.c stable/10/sys/kern/kern_sig.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/kern/kern_exec.c ============================================================================== --- stable/10/sys/kern/kern_exec.c Sun Aug 17 06:28:57 2014 (r270083) +++ stable/10/sys/kern/kern_exec.c Sun Aug 17 06:52:35 2014 (r270084) @@ -624,18 +624,17 @@ interpret: * handlers. In execsigs(), the new process will have its signals * reset. */ - PROC_LOCK(p); - oldcred = crcopysafe(p, newcred); if (sigacts_shared(p->p_sigacts)) { oldsigacts = p->p_sigacts; - PROC_UNLOCK(p); newsigacts = sigacts_alloc(); sigacts_copy(newsigacts, oldsigacts); - PROC_LOCK(p); - p->p_sigacts = newsigacts; } else oldsigacts = NULL; + PROC_LOCK(p); + if (oldsigacts) + p->p_sigacts = newsigacts; + oldcred = crcopysafe(p, newcred); /* Stop profiling */ stopprofclock(p); Modified: stable/10/sys/kern/kern_sig.c ============================================================================== --- stable/10/sys/kern/kern_sig.c Sun Aug 17 06:28:57 2014 (r270083) +++ stable/10/sys/kern/kern_sig.c Sun Aug 17 06:52:35 2014 (r270084) @@ -3463,10 +3463,6 @@ sigacts_copy(struct sigacts *dest, struc int sigacts_shared(struct sigacts *ps) { - int shared; - mtx_lock(&ps->ps_mtx); - shared = ps->ps_refcnt > 1; - mtx_unlock(&ps->ps_mtx); - return (shared); + return (ps->ps_refcnt > 1); }
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201408170652.s7H6qZeH028464>