ipc: SysVshmem segment can be unaligned

It's possible to create sysvshmem segment with size not being
multiple of page_size. And this very size will be reported
everywhere in the interfaces.

Support this type of segments too.
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>

criu/shmem.c

@@ -161,7 +161,7 @@ int fixup_sysv_shmems(void)
 			 * Same thing is checked in open_shmem_sysv() for
 			 * intermediate holes.
 			 */
-			if (att->first->start + si->size != att->prev_end) {
+			if (att->first->start + round_up(si->size, page_size()) != att->prev_end) {
 				pr_err("Sysv shmem %lx with tail hole not supported\n", si->shmid);
 				return -1;
 			}

test/zdtm/.gitignore

@@ -137,6 +137,7 @@
 /static/session02
 /static/session03
 /static/shm
+/static/shm-unaligned
 /static/shm-mp
 /static/sigaltstack
 /static/signalfd00

test/zdtm/static/Makefile

@@ -45,6 +45,7 @@ TST_NOFILE	=				\
 		inotify_system			\
 		inotify_system_nodel		\
 		shm				\
+		shm-unaligned			\
 		shm-mp				\
 		ptrace_sig			\
 		pipe00				\
@@ -297,6 +298,9 @@ $(TST_DIR_FILE:%=%.pid):	%.pid:	%
 cmdlinenv00.pid: cmdlinenv00
 	$(<D)/$(<F) --pidfile=$@ --outfile=$<.out --arg1=arg1 --arg2=arg2 --arg3=arg3
 
+shm-unaligned.pid: shm-unaligned
+	$(<D)/$(<F) --pidfile=$@ --outfile=$<.out --shmem_size=5000
+
 env00.pid:	env00
 	$(<D)/$(<F) --pidfile=$@ --outfile=$<.out --envname=ENV_00_TEST
 umask00.pid:	umask00

test/zdtm/static/shm-unaligned.c

+shm.c
\ No newline at end of file

test/zdtm/static/shm-unaligned.desc

+shm.desc
\ No newline at end of file