[PATCH 3/4] - v2 - IPC: use the target ID specified in procfs
[PATCH 03/04] This patch makes use of the target id specified by a previous write into /proc/self/task/<tid>/next_id as the id to use to allocate the next IPC object. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> --- include/linux/sysids.h | 7 +++++++ ipc/util.c | 41 +++++++++++++++++++++++++++++++++-------- kernel/nextid.c | 2 +- 3 files changed, 41 insertions(+), 9 deletions(-) Index: linux-2.6.25-rc8-mm2/include/linux/sysids.h =================================================================== --- linux-2.6.25-rc8-mm2.orig/include/linux/sysids.h 2008-04-17 16:03:07.000000000 +0200 +++ linux-2.6.25-rc8-mm2/include/linux/sysids.h 2008-04-17 17:05:54.000000000 +0200 @@ -37,9 +37,16 @@ struct sys_id { long *blocks[0]; }; +#define next_ipcid(tsk) ((tsk)->next_id \ + ? ((tsk)->next_id->nids \ + ? ID_AT((tsk)->next_id, 0) \ + : -1) \ + : -1) + extern ssize_t get_nextid(struct task_struct *, char *, size_t); extern int set_nextid(struct task_struct *, char *); extern int reset_nextid(struct task_struct *); +extern void id_blocks_free(struct sys_id *); static inline void exit_nextid(struct task_struct *tsk) { Index: linux-2.6.25-rc8-mm2/kernel/nextid.c =================================================================== --- linux-2.6.25-rc8-mm2.orig/kernel/nextid.c 2008-04-17 16:54:30.000000000 +0200 +++ linux-2.6.25-rc8-mm2/kernel/nextid.c 2008-04-17 17:06:43.000000000 +0200 @@ -49,7 +49,7 @@ out_undo_partial_alloc: return NULL; } -static void id_blocks_free(struct sys_id *ids) +void id_blocks_free(struct sys_id *ids) { if (ids == NULL) return; Index: linux-2.6.25-rc8-mm2/ipc/util.c =================================================================== --- linux-2.6.25-rc8-mm2.orig/ipc/util.c 2008-04-17 12:50:37.000000000 +0200 +++ linux-2.6.25-rc8-mm2/ipc/util.c 2008-04-17 17:09:37.000000000 +0200 @@ -260,6 +260,7 @@ int ipc_get_maxid(struct ipc_ids *ids) int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) { int id, err; + int next_id; if (size > IPCMNI) size = IPCMNI; @@ -267,20 +268,44 @@ int ipc_addid(struct ipc_ids* ids, struc if (ids->in_use >= size) return -ENOSPC; - err = idr_get_new(&ids->ipcs_idr, new, &id); - if (err) - return err; + next_id = next_ipcid(current); + + if (next_id >= 0) { + /* There is a target id specified, try to use it */ + int new_lid = next_id % SEQ_MULTIPLIER; + + if (next_id != + (new_lid + (next_id / SEQ_MULTIPLIER) * SEQ_MULTIPLIER)) + return -EINVAL; + + err = idr_get_new_above(&ids->ipcs_idr, new, new_lid, &id); + if (err) + return err; + if (id != new_lid) { + idr_remove(&ids->ipcs_idr, id); + return -EBUSY; + } + + new->id = next_id; + new->seq = next_id / SEQ_MULTIPLIER; + id_blocks_free(current->next_id); + current->next_id = NULL; + } else { + err = idr_get_new(&ids->ipcs_idr, new, &id); + if (err) + return err; + + new->seq = ids->seq++; + if (ids->seq > ids->seq_max) + ids->seq = 0; + new->id = ipc_buildid(id, new->seq); + } ids->in_use++; new->cuid = new->uid = current->euid; new->gid = new->cgid = current->egid; - new->seq = ids->seq++; - if(ids->seq > ids->seq_max) - ids->seq = 0; - - new->id = ipc_buildid(id, new->seq); spin_lock_init(&new->lock); new->deleted = 0; rcu_read_lock(); -- _______________________________________________ Containers mailing list Containers@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/containers