[PATCH 08/09] This patch makes idr_find() called locklessly in ipc_lock(), since the idr tree is now RCU protected. Signed-off-by: Nadia Derbey --- ipc/util.c | 9 --------- 1 file changed, 9 deletions(-) Index: linux-2.6.25-mm1/ipc/util.c =================================================================== --- linux-2.6.25-mm1.orig/ipc/util.c 2008-05-06 17:15:10.000000000 +0200 +++ linux-2.6.25-mm1/ipc/util.c 2008-05-07 09:56:20.000000000 +0200 @@ -688,10 +688,6 @@ void ipc64_perm_to_ipc_perm (struct ipc6 * Look for an id in the ipc ids idr and lock the associated ipc object. * * The ipc object is locked on exit. - * - * This is the routine that should be called when the rw_mutex is not already - * held, i.e. idr tree not protected: it protects the idr tree in read mode - * during the idr_find(). */ struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) @@ -699,18 +695,13 @@ struct kern_ipc_perm *ipc_lock(struct ip struct kern_ipc_perm *out; int lid = ipcid_to_idx(id); - down_read(&ids->rw_mutex); - rcu_read_lock(); out = idr_find(&ids->ipcs_idr, lid); if (out == NULL) { rcu_read_unlock(); - up_read(&ids->rw_mutex); return ERR_PTR(-EINVAL); } - up_read(&ids->rw_mutex); - spin_lock(&out->lock); /* ipc_rmid() may have already freed the ID while ipc_lock -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/