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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-17 16:56:17 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-17 16:56:17 -0800
commitfa7f578076a8814caa5371e9f4949e408140766d (patch)
tree8021be6f956e8a259523c394a01183797ce04422 /ipc/util.c
parent2dcd9c71c1ffa9a036e09047f60e08383bb0abb6 (diff)
parentd1b069f5febc850556cf49e9bb9092d3179c5be5 (diff)
Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton: - a bit more MM - procfs updates - dynamic-debug fixes - lib/ updates - checkpatch - epoll - nilfs2 - signals - rapidio - PID management cleanup and optimization - kcov updates - sysvipc updates - quite a few misc things all over the place * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (94 commits) EXPERT Kconfig menu: fix broken EXPERT menu include/asm-generic/topology.h: remove unused parent_node() macro arch/tile/include/asm/topology.h: remove unused parent_node() macro arch/sparc/include/asm/topology_64.h: remove unused parent_node() macro arch/sh/include/asm/topology.h: remove unused parent_node() macro arch/ia64/include/asm/topology.h: remove unused parent_node() macro drivers/pcmcia/sa1111_badge4.c: avoid unused function warning mm: add infrastructure for get_user_pages_fast() benchmarking sysvipc: make get_maxid O(1) again sysvipc: properly name ipc_addid() limit parameter sysvipc: duplicate lock comments wrt ipc_addid() sysvipc: unteach ids->next_id for !CHECKPOINT_RESTORE initramfs: use time64_t timestamps drivers/watchdog: make use of devm_register_reboot_notifier() kernel/reboot.c: add devm_register_reboot_notifier() kcov: update documentation Makefile: support flag -fsanitizer-coverage=trace-cmp kcov: support comparison operands collection kcov: remove pointless current != NULL check kernel/panic.c: add TAINT_AUX ...
Diffstat (limited to 'ipc/util.c')
-rw-r--r--ipc/util.c97
1 files changed, 55 insertions, 42 deletions
diff --git a/ipc/util.c b/ipc/util.c
index 79b30eee32cd..ff045fec8d83 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -116,13 +116,16 @@ int ipc_init_ids(struct ipc_ids *ids)
int err;
ids->in_use = 0;
ids->seq = 0;
- ids->next_id = -1;
init_rwsem(&ids->rwsem);
err = rhashtable_init(&ids->key_ht, &ipc_kht_params);
if (err)
return err;
idr_init(&ids->ipcs_idr);
ids->tables_initialized = true;
+ ids->max_id = -1;
+#ifdef CONFIG_CHECKPOINT_RESTORE
+ ids->next_id = -1;
+#endif
return 0;
}
@@ -186,41 +189,51 @@ static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
return NULL;
}
-/**
- * ipc_get_maxid - get the last assigned id
- * @ids: ipc identifier set
- *
- * Called with ipc_ids.rwsem held.
+#ifdef CONFIG_CHECKPOINT_RESTORE
+/*
+ * Specify desired id for next allocated IPC object.
*/
-int ipc_get_maxid(struct ipc_ids *ids)
+#define ipc_idr_alloc(ids, new) \
+ idr_alloc(&(ids)->ipcs_idr, (new), \
+ (ids)->next_id < 0 ? 0 : ipcid_to_idx((ids)->next_id),\
+ 0, GFP_NOWAIT)
+
+static inline int ipc_buildid(int id, struct ipc_ids *ids,
+ struct kern_ipc_perm *new)
{
- struct kern_ipc_perm *ipc;
- int max_id = -1;
- int total, id;
+ if (ids->next_id < 0) { /* default, behave as !CHECKPOINT_RESTORE */
+ new->seq = ids->seq++;
+ if (ids->seq > IPCID_SEQ_MAX)
+ ids->seq = 0;
+ } else {
+ new->seq = ipcid_to_seqx(ids->next_id);
+ ids->next_id = -1;
+ }
- if (ids->in_use == 0)
- return -1;
+ return SEQ_MULTIPLIER * new->seq + id;
+}
- if (ids->in_use == IPCMNI)
- return IPCMNI - 1;
+#else
+#define ipc_idr_alloc(ids, new) \
+ idr_alloc(&(ids)->ipcs_idr, (new), 0, 0, GFP_NOWAIT)
- /* Look for the last assigned id */
- total = 0;
- for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
- ipc = idr_find(&ids->ipcs_idr, id);
- if (ipc != NULL) {
- max_id = id;
- total++;
- }
- }
- return max_id;
+static inline int ipc_buildid(int id, struct ipc_ids *ids,
+ struct kern_ipc_perm *new)
+{
+ new->seq = ids->seq++;
+ if (ids->seq > IPCID_SEQ_MAX)
+ ids->seq = 0;
+
+ return SEQ_MULTIPLIER * new->seq + id;
}
+#endif /* CONFIG_CHECKPOINT_RESTORE */
+
/**
* ipc_addid - add an ipc identifier
* @ids: ipc identifier set
* @new: new ipc permission set
- * @size: limit for the number of used ids
+ * @limit: limit for the number of used ids
*
* Add an entry 'new' to the ipc ids idr. The permissions object is
* initialised and the first free entry is set up and the id assigned
@@ -229,17 +242,16 @@ int ipc_get_maxid(struct ipc_ids *ids)
*
* Called with writer ipc_ids.rwsem held.
*/
-int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
+int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int limit)
{
kuid_t euid;
kgid_t egid;
int id, err;
- int next_id = ids->next_id;
- if (size > IPCMNI)
- size = IPCMNI;
+ if (limit > IPCMNI)
+ limit = IPCMNI;
- if (!ids->tables_initialized || ids->in_use >= size)
+ if (!ids->tables_initialized || ids->in_use >= limit)
return -ENOSPC;
idr_preload(GFP_KERNEL);
@@ -254,9 +266,7 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
new->cuid = new->uid = euid;
new->gid = new->cgid = egid;
- id = idr_alloc(&ids->ipcs_idr, new,
- (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0,
- GFP_NOWAIT);
+ id = ipc_idr_alloc(ids, new);
idr_preload_end();
if (id >= 0 && new->key != IPC_PRIVATE) {
@@ -274,17 +284,11 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
}
ids->in_use++;
+ if (id > ids->max_id)
+ ids->max_id = id;
- if (next_id < 0) {
- new->seq = ids->seq++;
- if (ids->seq > IPCID_SEQ_MAX)
- ids->seq = 0;
- } else {
- new->seq = ipcid_to_seqx(next_id);
- ids->next_id = -1;
- }
+ new->id = ipc_buildid(id, ids, new);
- new->id = ipc_buildid(id, new->seq);
return id;
}
@@ -429,6 +433,15 @@ void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
ipc_kht_remove(ids, ipcp);
ids->in_use--;
ipcp->deleted = true;
+
+ if (unlikely(lid == ids->max_id)) {
+ do {
+ lid--;
+ if (lid == -1)
+ break;
+ } while (!idr_find(&ids->ipcs_idr, lid));
+ ids->max_id = lid;
+ }
}
/**

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