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authorDavidlohr Bueso <dave@stgolabs.net>2017-11-17 15:31:08 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-17 16:10:04 -0800
commitb8fd99838435f9b420c3e848192bd43abc648b7f (patch)
tree793a6390f29e27fcd9b87ba8b65c2480627491af
parentinitramfs: use time64_t timestamps (diff)
downloadlinux-dev-b8fd99838435f9b420c3e848192bd43abc648b7f.tar.xz
linux-dev-b8fd99838435f9b420c3e848192bd43abc648b7f.zip
sysvipc: unteach ids->next_id for !CHECKPOINT_RESTORE
Patch series "sysvipc: ipc-key management improvements". Here are a few improvements I spotted while eyeballing Guillaume's rhashtable implementation for ipc keys. The first and fourth patches are the interesting ones, the middle two are trivial. This patch (of 4): The next_id object-allocation functionality was introduced in commit 03f595668017 ("ipc: add sysctl to specify desired next object id"). Given that these new entries are _only_ exported under the CONFIG_CHECKPOINT_RESTORE option, there is no point for the common case to even know about ->next_id. As such rewrite ipc_buildid() such that it can do away with the field as well as unnecessary branches when adding a new identifier. The end result also better differentiates both cases, so the code ends up being cleaner; albeit the small duplications regarding the default case. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20170831172049.14576-2-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/ipc_namespace.h2
-rw-r--r--ipc/util.c60
-rw-r--r--ipc/util.h5
3 files changed, 47 insertions, 20 deletions
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 474812abe773..d7cf3a850853 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -19,7 +19,9 @@ struct ipc_ids {
bool tables_initialized;
struct rw_semaphore rwsem;
struct idr ipcs_idr;
+#ifdef CONFIG_CHECKPOINT_RESTORE
int next_id;
+#endif
struct rhashtable key_ht;
};
diff --git a/ipc/util.c b/ipc/util.c
index 79b30eee32cd..429c06bdb8ef 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -116,13 +116,15 @@ 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;
+#ifdef CONFIG_CHECKPOINT_RESTORE
+ ids->next_id = -1;
+#endif
return 0;
}
@@ -216,6 +218,46 @@ int ipc_get_maxid(struct ipc_ids *ids)
return max_id;
}
+#ifdef CONFIG_CHECKPOINT_RESTORE
+/*
+ * Specify desired id for next allocated IPC object.
+ */
+#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)
+{
+ 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;
+ }
+
+ return SEQ_MULTIPLIER * new->seq + id;
+}
+
+#else
+#define ipc_idr_alloc(ids, new) \
+ idr_alloc(&(ids)->ipcs_idr, (new), 0, 0, GFP_NOWAIT)
+
+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
@@ -234,7 +276,6 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
kuid_t euid;
kgid_t egid;
int id, err;
- int next_id = ids->next_id;
if (size > IPCMNI)
size = IPCMNI;
@@ -254,9 +295,7 @@ 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 +313,8 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
}
ids->in_use++;
+ new->id = ipc_buildid(id, ids, new);
- 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, new->seq);
return id;
}
diff --git a/ipc/util.h b/ipc/util.h
index 579112d90016..0cd6201fe63a 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -146,11 +146,6 @@ extern struct msg_msg *load_msg(const void __user *src, size_t len);
extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
-static inline int ipc_buildid(int id, int seq)
-{
- return SEQ_MULTIPLIER * seq + id;
-}
-
static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
{
return uid / SEQ_MULTIPLIER != ipcp->seq;