Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:

 - a couple of hotfixes

 - almost all of the rest of MM

 - lib/ updates

 - binfmt_elf updates

 - autofs updates

 - quite a lot of misc fixes and updates
    - reiserfs, fatfs
    - signals
    - exec
    - cpumask
    - rapidio
    - sysctl
    - pids
    - eventfd
    - gcov
    - panic
    - pps

 - gdb script updates

 - ipc updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (126 commits)
  mm: memcontrol: fix NUMA round-robin reclaim at intermediate level
  mm: memcontrol: fix recursive statistics correctness & scalabilty
  mm: memcontrol: move stat/event counting functions out-of-line
  mm: memcontrol: make cgroup stats and events query API explicitly local
  drivers/virt/fsl_hypervisor.c: prevent integer overflow in ioctl
  drivers/virt/fsl_hypervisor.c: dereferencing error pointers in ioctl
  mm, memcg: rename ambiguously named memory.stat counters and functions
  arch: remove <asm/sizes.h> and <asm-generic/sizes.h>
  treewide: replace #include <asm/sizes.h> with #include <linux/sizes.h>
  fs/block_dev.c: Remove duplicate header
  fs/cachefiles/namei.c: remove duplicate header
  include/linux/sched/signal.h: replace `tsk' with `task'
  fs/coda/psdev.c: remove duplicate header
  ipc: do cyclic id allocation for the ipc object.
  ipc: conserve sequence numbers in ipcmni_extend mode
  ipc: allow boot time extension of IPCMNI from 32k to 16M
  ipc/mqueue: optimize msg_get()
  ipc/mqueue: remove redundant wq task assignment
  ipc: prevent lockup on alloc_msg and free_msg
  scripts/gdb: print cached rate in lx-clk-summary
  ...

1 files changed, 39 insertions, 9 deletions

diff --git a/ipc/util.c b/ipc/util.c
index 095274a871f8..d126d156efc6 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -109,7 +109,7 @@ static const struct rhashtable_params ipc_kht_params = {
  * @ids: ipc identifier set
  *
  * Set up the sequence range to use for the ipc identifier range (limited
- * below IPCMNI) then initialise the keys hashtable and ids idr.
+ * below ipc_mni) then initialise the keys hashtable and ids idr.
  */
 void ipc_init_ids(struct ipc_ids *ids)
 {
@@ -119,6 +119,7 @@ void ipc_init_ids(struct ipc_ids *ids)
 	rhashtable_init(&ids->key_ht, &ipc_kht_params);
 	idr_init(&ids->ipcs_idr);
 	ids->max_idx = -1;
+	ids->last_idx = -1;
 #ifdef CONFIG_CHECKPOINT_RESTORE
 	ids->next_id = -1;
 #endif
@@ -192,6 +193,10 @@ static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
  *
  * The caller must own kern_ipc_perm.lock.of the new object.
  * On error, the function returns a (negative) error code.
+ *
+ * To conserve sequence number space, especially with extended ipc_mni,
+ * the sequence number is incremented only when the returned ID is less than
+ * the last one.
  */
 static inline int ipc_idr_alloc(struct ipc_ids *ids, struct kern_ipc_perm *new)
 {
@@ -215,17 +220,42 @@ static inline int ipc_idr_alloc(struct ipc_ids *ids, struct kern_ipc_perm *new)
 	 */
 
 	if (next_id < 0) { /* !CHECKPOINT_RESTORE or next_id is unset */
-		new->seq = ids->seq++;
-		if (ids->seq > IPCID_SEQ_MAX)
-			ids->seq = 0;
-		idx = idr_alloc(&ids->ipcs_idr, new, 0, 0, GFP_NOWAIT);
+		int max_idx;
+
+		max_idx = max(ids->in_use*3/2, ipc_min_cycle);
+		max_idx = min(max_idx, ipc_mni);
+
+		/* allocate the idx, with a NULL struct kern_ipc_perm */
+		idx = idr_alloc_cyclic(&ids->ipcs_idr, NULL, 0, max_idx,
+					GFP_NOWAIT);
+
+		if (idx >= 0) {
+			/*
+			 * idx got allocated successfully.
+			 * Now calculate the sequence number and set the
+			 * pointer for real.
+			 */
+			if (idx <= ids->last_idx) {
+				ids->seq++;
+				if (ids->seq >= ipcid_seq_max())
+					ids->seq = 0;
+			}
+			ids->last_idx = idx;
+
+			new->seq = ids->seq;
+			/* no need for smp_wmb(), this is done
+			 * inside idr_replace, as part of
+			 * rcu_assign_pointer
+			 */
+			idr_replace(&ids->ipcs_idr, new, idx);
+		}
 	} else {
 		new->seq = ipcid_to_seqx(next_id);
 		idx = idr_alloc(&ids->ipcs_idr, new, ipcid_to_idx(next_id),
 				0, GFP_NOWAIT);
 	}
 	if (idx >= 0)
-		new->id = SEQ_MULTIPLIER * new->seq + idx;
+		new->id = (new->seq << ipcmni_seq_shift()) + idx;
 	return idx;
 }
 
@@ -253,8 +283,8 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int limit)
 	/* 1) Initialize the refcount so that ipc_rcu_putref works */
 	refcount_set(&new->refcount, 1);
 
-	if (limit > IPCMNI)
-		limit = IPCMNI;
+	if (limit > ipc_mni)
+		limit = ipc_mni;
 
 	if (ids->in_use >= limit)
 		return -ENOSPC;
@@ -737,7 +767,7 @@ static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
 	if (total >= ids->in_use)
 		return NULL;
 
-	for (; pos < IPCMNI; pos++) {
+	for (; pos < ipc_mni; pos++) {
 		ipc = idr_find(&ids->ipcs_idr, pos);
 		if (ipc != NULL) {
 			*new_pos = pos + 1;