[patch] Minor PAGG attach/detach semantic change for 2.6.11

Kingsley Cheung <[email protected]> Fri, 17 Jun 2005 11:45:12 +1000

Newsgroups	gmane.linux.process-aggregates
Message-ID	<[email protected]>

Hi Erik,

While testing the propagation of pagg_attach errors to fork() I
noticed that the detach callback is called again for the client
responsible for the error.  Perhaps you may have a different opinion
on this, but IMHO this is unnecessary as the client passing the
failure error up should have already cleaned up any data in its pagg
structure during its attach callback.

I've atttached a patch that applies (with some fuzz) correctly to
2.6.11 that avoids this unncessary call to the client's detach
callback.  Please consider applying.

Thanks, 
-- 
		Kingsley

pagg.patch (text/plain, 1.9 KB)

Index: kernel/fork.c
===================================================================
RCS file: /export/cvsroot/SLES9_kernel/kernel/fork.c,v
retrieving revision 1.1.1.3.12.1
diff -u -r1.1.1.3.12.1 fork.c
--- kernel/fork.c	27 May 2005 05:17:01 -0000	1.1.1.3.12.1
+++ kernel/fork.c	17 Jun 2005 00:39:33 -0000
@@ -1086,7 +1086,7 @@
 	if (sigismember(&current->pending.signal, SIGKILL)) {
 		write_unlock_irq(&tasklist_lock);
 		retval = -EINTR;
-		goto bad_fork_cleanup_namespace;
+		goto bad_fork_cleanup_pagg;
 	}
 
 	/* CLONE_PARENT re-uses the old parent */
@@ -1107,7 +1107,7 @@
 			spin_unlock(&current->sighand->siglock);
 			write_unlock_irq(&tasklist_lock);
 			retval = -EAGAIN;
-			goto bad_fork_cleanup_namespace;
+			goto bad_fork_cleanup_pagg;
 		}
 		p->group_leader = current->group_leader;
 
@@ -1149,8 +1149,9 @@
 		return ERR_PTR(retval);
 	return p;
 
-bad_fork_cleanup_namespace:
+bad_fork_cleanup_pagg:
 	pagg_detach(p);
+bad_fork_cleanup_namespace:
 	exit_namespace(p);
 bad_fork_cleanup_mm:
 	exit_mm(p);
Index: kernel/pagg.c
===================================================================
RCS file: /export/cvsroot/SLES9_kernel/kernel/Attic/pagg.c,v
retrieving revision 1.1.1.1.12.1
diff -u -r1.1.1.1.12.1 pagg.c
--- kernel/pagg.c	27 May 2005 05:17:01 -0000	1.1.1.1.12.1
+++ kernel/pagg.c	17 Jun 2005 00:39:33 -0000
@@ -410,14 +410,15 @@
 			goto error_return;
 		}
 		ret = to_pagg->hook->attach(to_task, to_pagg, from_pagg->data);
-
-		if (ret < 0) {
-			/* Propagates to copy_process as a fork failure */
-			goto error_return;
-		}
-		else if (ret > 0) {
-			/* Success, but attach function pointer doesn't want grouping */
+		if (ret) {
+			/* Negative error propagates to copy_process
+			 * as a fork failure.  Otherwise we have
+			 * success, but the attach function pointer
+			 * doesn't want grouping. 
+			 */
 			pagg_free(to_pagg);
+			if (ret < 0)
+				goto error_return;
 		}
 	}