rst-malloc: s/rst_mem_cpos/rst_mem_align_cpos

Since we need to align some allocations (but not most of them), let's
always align them when checking the current position.

v2: always rst_mem_align() before the beginning of each "set" of
    allocations
v3: merge rst_mem_align and rst_mem_cpos
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
CC: Cyrill Gorcunov <gorcunov@gmail.com>
CC: Andrey Vagin <avagin@openvz.org>
Acked-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

cr-restore.c

@@ -775,7 +775,7 @@ static int collect_child_pids(int state, int *n)
 		if (pi->state != state)
 			continue;
 
-		child = rst_mem_alloc_cont(sizeof(*child), RM_PRIVATE);
+		child = rst_mem_alloc(sizeof(*child), RM_PRIVATE);
 		if (!child)
 			return -1;
 
@@ -788,13 +788,13 @@ static int collect_child_pids(int state, int *n)
 
 static int collect_helper_pids()
 {
-	helpers_pos = rst_mem_cpos(RM_PRIVATE);
+	helpers_pos = rst_mem_align_cpos(RM_PRIVATE);
 	return collect_child_pids(TASK_HELPER, &n_helpers);
 }
 
 static int collect_zombie_pids()
 {
-	zombies_pos = rst_mem_cpos(RM_PRIVATE);
+	zombies_pos = rst_mem_align_cpos(RM_PRIVATE);
 	return collect_child_pids(TASK_DEAD, &n_zombies);
 }
 
@@ -2133,7 +2133,7 @@ out:
 
 static int prepare_task_entries(void)
 {
-	task_entries_pos = rst_mem_cpos(RM_SHREMAP);
+	task_entries_pos = rst_mem_align_cpos(RM_SHREMAP);
 	task_entries = rst_mem_alloc(sizeof(*task_entries), RM_SHREMAP);
 	if (!task_entries) {
 		pr_perror("Can't map shmem");
@@ -2432,7 +2432,7 @@ static int prepare_posix_timers_from_fd(int pid)
 		if (ret <= 0)
 			break;
 
-		t = rst_mem_alloc_cont(sizeof(struct restore_posix_timer), RM_PRIVATE);
+		t = rst_mem_alloc(sizeof(struct restore_posix_timer), RM_PRIVATE);
 		if (!t)
 			break;
 
@@ -2457,14 +2457,14 @@ static int prepare_posix_timers(int pid, CoreEntry *core)
 	TaskTimersEntry *tte = core->tc->timers;
 	struct restore_posix_timer *t;
 
-	posix_timers_cpos = rst_mem_cpos(RM_PRIVATE);
+	posix_timers_cpos = rst_mem_align_cpos(RM_PRIVATE);
 
 	if (!tte)
 		return prepare_posix_timers_from_fd(pid);
 
 	posix_timers_nr = tte->n_posix;
 	for (i = 0; i < posix_timers_nr; i++) {
-		t = rst_mem_alloc_cont(sizeof(struct restore_posix_timer), RM_PRIVATE);
+		t = rst_mem_alloc(sizeof(struct restore_posix_timer), RM_PRIVATE);
 		if (!t)
 			goto out;
 
@@ -2623,7 +2623,7 @@ static int prepare_rlimits_from_fd(int pid)
 		if (ret <= 0)
 			break;
 
-		r = rst_mem_alloc_cont(sizeof(*r), RM_PRIVATE);
+		r = rst_mem_alloc(sizeof(*r), RM_PRIVATE);
 		if (!r) {
 			pr_err("Can't allocate memory for resource %d\n",
 			       rlims_nr);
@@ -2654,13 +2654,13 @@ static int prepare_rlimits(int pid, CoreEntry *core)
 	TaskRlimitsEntry *rls = core->tc->rlimits;
 	struct rlimit *r;
 
-	rlims_cpos = rst_mem_cpos(RM_PRIVATE);
+	rlims_cpos = rst_mem_align_cpos(RM_PRIVATE);
 
 	if (!rls)
 		return prepare_rlimits_from_fd(pid);
 
 	for (i = 0; i < rls->n_rlimits; i++) {
-		r = rst_mem_alloc_cont(sizeof(*r), RM_PRIVATE);
+		r = rst_mem_alloc(sizeof(*r), RM_PRIVATE);
 		if (!r) {
 			pr_err("Can't allocate memory for resource %d\n", i);
 			return -1;
@@ -2684,7 +2684,7 @@ static int signal_to_mem(SiginfoEntry *sie)
 	siginfo_t *info, *t;
 
 	info = (siginfo_t *) sie->siginfo.data;
-	t = rst_mem_alloc_cont(sizeof(siginfo_t), RM_PRIVATE);
+	t = rst_mem_alloc(sizeof(siginfo_t), RM_PRIVATE);
 	if (!t)
 		return -1;
 
@@ -2749,7 +2749,7 @@ static int prepare_signals(int pid, CoreEntry *leader_core)
 {
 	int ret = -1, i;
 
-	siginfo_cpos = rst_mem_cpos(RM_PRIVATE);
+	siginfo_cpos = rst_mem_align_cpos(RM_PRIVATE);
 	siginfo_priv_nr = xmalloc(sizeof(int) * current->nr_threads);
 	if (siginfo_priv_nr == NULL)
 		goto out;
@@ -2802,7 +2802,7 @@ static void rst_reloc_creds(struct thread_restore_args *thread_args,
 static struct thread_creds_args *
 rst_prep_creds_args(CredsEntry *ce, unsigned long *prev_pos)
 {
-	unsigned long this_pos = rst_mem_cpos(RM_PRIVATE);
+	unsigned long this_pos;
 	struct thread_creds_args *args;
 
 	if (!verify_cap_size(ce)) {
@@ -2812,8 +2812,9 @@ rst_prep_creds_args(CredsEntry *ce, unsigned long *prev_pos)
 		return ERR_PTR(-EINVAL);
 	}
 
+	this_pos = rst_mem_align_cpos(RM_PRIVATE);
 
-	args = rst_mem_alloc_cont(sizeof(*args), RM_PRIVATE);
+	args = rst_mem_alloc(sizeof(*args), RM_PRIVATE);
 	if (!args)
 		return ERR_PTR(-ENOMEM);
 
@@ -2838,7 +2839,7 @@ rst_prep_creds_args(CredsEntry *ce, unsigned long *prev_pos)
 			size_t lsm_profile_len;
 			char *lsm_profile;
 
-			args->mem_lsm_profile_pos = rst_mem_cpos(RM_PRIVATE);
+			args->mem_lsm_profile_pos = rst_mem_align_cpos(RM_PRIVATE);
 			lsm_profile_len = strlen(rendered);
 			lsm_profile = rst_mem_alloc(lsm_profile_len + 1, RM_PRIVATE);
 			if (!lsm_profile) {
@@ -2874,7 +2875,7 @@ rst_prep_creds_args(CredsEntry *ce, unsigned long *prev_pos)
 	if (ce->n_groups) {
 		unsigned int *groups;
 
-		args->mem_groups_pos = rst_mem_cpos(RM_PRIVATE);
+		args->mem_groups_pos = rst_mem_align_cpos(RM_PRIVATE);
 		groups = rst_mem_alloc(ce->n_groups * sizeof(u32), RM_PRIVATE);
 		if (!groups)
 			return ERR_PTR(-ENOMEM);
@@ -2944,7 +2945,7 @@ static int rst_prep_creds(pid_t pid, CoreEntry *core, unsigned long *creds_pos)
 		return 0;
 	}
 
-	*creds_pos = rst_mem_cpos(RM_PRIVATE);
+	*creds_pos = rst_mem_align_cpos(RM_PRIVATE);
 
 	/*
 	 * Old format: one Creds per task carried in own image file.
@@ -3016,11 +3017,11 @@ static int sigreturn_restore(pid_t pid, CoreEntry *core)
 	 * walk them and m(un|re)map.
 	 */
 
-	tgt_vmas = rst_mem_cpos(RM_PRIVATE);
+	tgt_vmas = rst_mem_align_cpos(RM_PRIVATE);
 	list_for_each_entry(vma, &vmas->h, list) {
 		VmaEntry *vme;
 
-		vme = rst_mem_alloc_cont(sizeof(*vme), RM_PRIVATE);
+		vme = rst_mem_alloc(sizeof(*vme), RM_PRIVATE);
 		if (!vme)
 			goto err_nv;
 
@@ -3034,11 +3035,11 @@ static int sigreturn_restore(pid_t pid, CoreEntry *core)
 	 * Put info about AIO rings, they will get remapped
 	 */
 
-	aio_rings = rst_mem_cpos(RM_PRIVATE);
+	aio_rings = rst_mem_align_cpos(RM_PRIVATE);
 	for (i = 0; i < mm->n_aios; i++) {
 		struct rst_aio_ring *raio;
 
-		raio = rst_mem_alloc_cont(sizeof(*raio), RM_PRIVATE);
+		raio = rst_mem_alloc(sizeof(*raio), RM_PRIVATE);
 		if (!raio)
 			goto err_nv;
 

include/rst-malloc.h

@@ -47,10 +47,10 @@ enum {
 extern void rst_mem_switch_to_private(void);
 /*
  * Reports a cookie of a current shared buffer position, that
- * can later be used in rst_mem_cpos() to find out the object
- * pointer.
+ * can later be used in rst_mem_remap_ptr() to find out the object
+ * pointer in the restorer blob.
  */
-extern unsigned long rst_mem_cpos(int type);
+extern unsigned long rst_mem_align_cpos(int type);
 extern void *rst_mem_remap_ptr(unsigned long pos, int type);
 /*
  * Allocate and free objects. We don't need to free arbitrary
@@ -58,8 +58,13 @@ extern void *rst_mem_remap_ptr(unsigned long pos, int type);
  * last object can be freed (pop-ed from buffer).
  */
 extern void *rst_mem_alloc(unsigned long size, int type);
-extern void *rst_mem_alloc_cont(unsigned long size, int type);
 extern void rst_mem_free_last(int type);
+
+/* Word-align the current freelist pointer for the next allocation. If we don't
+ * align pointers, some futex and atomic operations can fail.
+ */
+extern void rst_mem_align(int type);
+
 /*
  * Routines to remap SHREMAP and PRIVATE into restorer address space
  */

rst-malloc.c

@@ -124,11 +124,14 @@ void rst_mem_switch_to_private(void)
 	rst_mems[RM_PRIVATE].enabled = true;
 }
 
-unsigned long rst_mem_cpos(int type)
+unsigned long rst_mem_align_cpos(int type)
 {
 	struct rst_mem_type_s *t = &rst_mems[type];
 	BUG_ON(!t->remapable || !t->enabled);
-	return ((void*) round_up((unsigned long)t->free_mem, sizeof(void *))) - t->buf;
+
+	t->free_mem = (void *) round_up((unsigned long)t->free_mem, sizeof(void *));
+
+	return t->free_mem - t->buf;
 }
 
 void *rst_mem_remap_ptr(unsigned long pos, int type)
@@ -138,7 +141,7 @@ void *rst_mem_remap_ptr(unsigned long pos, int type)
 	return t->buf + pos;
 }
 
-static void *__rst_mem_alloc(unsigned long size, int type)
+void *rst_mem_alloc(unsigned long size, int type)
 {
 	struct rst_mem_type_s *t = &rst_mems[type];
 	void *ret;
@@ -158,24 +161,6 @@ static void *__rst_mem_alloc(unsigned long size, int type)
 	return ret;
 }
 
-void *rst_mem_alloc(unsigned long size, int type)
-{
-	struct rst_mem_type_s *t = &rst_mems[type];
-
-	t->free_mem = (void *) round_up((unsigned long)t->free_mem, sizeof(void *));
-
-	return __rst_mem_alloc(size, type);
-}
-
-/* Allocate memory without gaps with a previous slice */
-void *rst_mem_alloc_cont(unsigned long size, int type)
-{
-	struct rst_mem_type_s *t = &rst_mems[type];
-	BUG_ON(!t->remapable);
-
-	return __rst_mem_alloc(size, type);
-}
-
 void rst_mem_free_last(int type)
 {
 	struct rst_mem_type_s *t = &rst_mems[type];

seccomp.c

@@ -230,7 +230,7 @@ int seccomp_filters_get_rst_pos(CoreEntry *core, int *count, unsigned long *pos)
 	}
 
 	*count = 0;
-	*pos = rst_mem_cpos(RM_PRIVATE);
+	*pos = rst_mem_align_cpos(RM_PRIVATE);
 
 	BUG_ON(core->tc->seccomp_filter > se->n_seccomp_filters);
 	sf = se->seccomp_filters[core->tc->seccomp_filter];

sk-tcp.c

@@ -678,7 +678,7 @@ int rst_tcp_socks_prep(void)
 {
 	struct inet_sk_info *ii;
 
-	rst_tcp_socks_cpos = rst_mem_cpos(RM_PRIVATE);
+	rst_tcp_socks_cpos = rst_mem_align_cpos(RM_PRIVATE);
 	list_for_each_entry(ii, &rst_tcp_repair_sockets, rlist) {
 		struct rst_tcp_sock *rs;
 
@@ -689,7 +689,7 @@ int rst_tcp_socks_prep(void)
 		if (ii->sk_fd == -1)
 			continue;
 
-		rs = rst_mem_alloc_cont(sizeof(*rs), RM_PRIVATE);
+		rs = rst_mem_alloc(sizeof(*rs), RM_PRIVATE);
 		if (!rs)
 			return -1;
 

timerfd.c

@@ -115,11 +115,11 @@ int rst_timerfd_prep(void)
 	struct timerfd_info *ti;
 	struct restore_timerfd *t;
 
-	rst_timerfd_cpos = rst_mem_cpos(RM_PRIVATE);
+	rst_timerfd_cpos = rst_mem_align_cpos(RM_PRIVATE);
 	list_for_each_entry(ti, &rst_timerfds, rlist) {
 		TimerfdEntry *tfe = ti->tfe;
 
-		t = rst_mem_alloc_cont(sizeof(*t), RM_PRIVATE);
+		t = rst_mem_alloc(sizeof(*t), RM_PRIVATE);
 		if (!t)
 			return -1;