Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
[linux-2.6-block.git] / drivers / infiniband / core / umem_odp.c
index bd01c77aeef03d56dff3771c2dbe4d35e046be8d..f67a30fda1ed9a332cd5aedcf417ebd00c1019a9 100644 (file)
@@ -82,7 +82,7 @@ static void ib_umem_notifier_release(struct mmu_notifier *mn,
        struct rb_node *node;
 
        down_read(&per_mm->umem_rwsem);
-       if (!per_mm->active)
+       if (!per_mm->mn.users)
                goto out;
 
        for (node = rb_first_cached(&per_mm->umem_tree); node;
@@ -96,7 +96,7 @@ static void ib_umem_notifier_release(struct mmu_notifier *mn,
                 */
                ib_umem_notifier_start_account(umem_odp);
                complete_all(&umem_odp->notifier_completion);
-               umem_odp->umem.context->device->ops.invalidate_range(
+               umem_odp->umem.ibdev->ops.invalidate_range(
                        umem_odp, ib_umem_start(umem_odp),
                        ib_umem_end(umem_odp));
        }
@@ -109,7 +109,7 @@ static int invalidate_range_start_trampoline(struct ib_umem_odp *item,
                                             u64 start, u64 end, void *cookie)
 {
        ib_umem_notifier_start_account(item);
-       item->umem.context->device->ops.invalidate_range(item, start, end);
+       item->umem.ibdev->ops.invalidate_range(item, start, end);
        return 0;
 }
 
@@ -125,10 +125,10 @@ static int ib_umem_notifier_invalidate_range_start(struct mmu_notifier *mn,
        else if (!down_read_trylock(&per_mm->umem_rwsem))
                return -EAGAIN;
 
-       if (!per_mm->active) {
+       if (!per_mm->mn.users) {
                up_read(&per_mm->umem_rwsem);
                /*
-                * At this point active is permanently set and visible to this
+                * At this point users is permanently zero and visible to this
                 * CPU without a lock, that fact is relied on to skip the unlock
                 * in range_end.
                 */
@@ -158,7 +158,7 @@ static void ib_umem_notifier_invalidate_range_end(struct mmu_notifier *mn,
        struct ib_ucontext_per_mm *per_mm =
                container_of(mn, struct ib_ucontext_per_mm, mn);
 
-       if (unlikely(!per_mm->active))
+       if (unlikely(!per_mm->mn.users))
                return;
 
        rbt_ib_umem_for_each_in_range(&per_mm->umem_tree, range->start,
@@ -167,122 +167,47 @@ static void ib_umem_notifier_invalidate_range_end(struct mmu_notifier *mn,
        up_read(&per_mm->umem_rwsem);
 }
 
-static const struct mmu_notifier_ops ib_umem_notifiers = {
-       .release                    = ib_umem_notifier_release,
-       .invalidate_range_start     = ib_umem_notifier_invalidate_range_start,
-       .invalidate_range_end       = ib_umem_notifier_invalidate_range_end,
-};
-
-static void remove_umem_from_per_mm(struct ib_umem_odp *umem_odp)
-{
-       struct ib_ucontext_per_mm *per_mm = umem_odp->per_mm;
-
-       down_write(&per_mm->umem_rwsem);
-       interval_tree_remove(&umem_odp->interval_tree, &per_mm->umem_tree);
-       complete_all(&umem_odp->notifier_completion);
-       up_write(&per_mm->umem_rwsem);
-}
-
-static struct ib_ucontext_per_mm *alloc_per_mm(struct ib_ucontext *ctx,
-                                              struct mm_struct *mm)
+static struct mmu_notifier *ib_umem_alloc_notifier(struct mm_struct *mm)
 {
        struct ib_ucontext_per_mm *per_mm;
-       int ret;
 
        per_mm = kzalloc(sizeof(*per_mm), GFP_KERNEL);
        if (!per_mm)
                return ERR_PTR(-ENOMEM);
 
-       per_mm->context = ctx;
-       per_mm->mm = mm;
        per_mm->umem_tree = RB_ROOT_CACHED;
        init_rwsem(&per_mm->umem_rwsem);
-       per_mm->active = true;
 
+       WARN_ON(mm != current->mm);
        rcu_read_lock();
        per_mm->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
        rcu_read_unlock();
-
-       WARN_ON(mm != current->mm);
-
-       per_mm->mn.ops = &ib_umem_notifiers;
-       ret = mmu_notifier_register(&per_mm->mn, per_mm->mm);
-       if (ret) {
-               dev_err(&ctx->device->dev,
-                       "Failed to register mmu_notifier %d\n", ret);
-               goto out_pid;
-       }
-
-       list_add(&per_mm->ucontext_list, &ctx->per_mm_list);
-       return per_mm;
-
-out_pid:
-       put_pid(per_mm->tgid);
-       kfree(per_mm);
-       return ERR_PTR(ret);
-}
-
-static struct ib_ucontext_per_mm *get_per_mm(struct ib_umem_odp *umem_odp)
-{
-       struct ib_ucontext *ctx = umem_odp->umem.context;
-       struct ib_ucontext_per_mm *per_mm;
-
-       lockdep_assert_held(&ctx->per_mm_list_lock);
-
-       /*
-        * Generally speaking we expect only one or two per_mm in this list,
-        * so no reason to optimize this search today.
-        */
-       list_for_each_entry(per_mm, &ctx->per_mm_list, ucontext_list) {
-               if (per_mm->mm == umem_odp->umem.owning_mm)
-                       return per_mm;
-       }
-
-       return alloc_per_mm(ctx, umem_odp->umem.owning_mm);
-}
-
-static void free_per_mm(struct rcu_head *rcu)
-{
-       kfree(container_of(rcu, struct ib_ucontext_per_mm, rcu));
+       return &per_mm->mn;
 }
 
-static void put_per_mm(struct ib_umem_odp *umem_odp)
+static void ib_umem_free_notifier(struct mmu_notifier *mn)
 {
-       struct ib_ucontext_per_mm *per_mm = umem_odp->per_mm;
-       struct ib_ucontext *ctx = umem_odp->umem.context;
-       bool need_free;
-
-       mutex_lock(&ctx->per_mm_list_lock);
-       umem_odp->per_mm = NULL;
-       per_mm->odp_mrs_count--;
-       need_free = per_mm->odp_mrs_count == 0;
-       if (need_free)
-               list_del(&per_mm->ucontext_list);
-       mutex_unlock(&ctx->per_mm_list_lock);
-
-       if (!need_free)
-               return;
-
-       /*
-        * NOTE! mmu_notifier_unregister() can happen between a start/end
-        * callback, resulting in an start/end, and thus an unbalanced
-        * lock. This doesn't really matter to us since we are about to kfree
-        * the memory that holds the lock, however LOCKDEP doesn't like this.
-        */
-       down_write(&per_mm->umem_rwsem);
-       per_mm->active = false;
-       up_write(&per_mm->umem_rwsem);
+       struct ib_ucontext_per_mm *per_mm =
+               container_of(mn, struct ib_ucontext_per_mm, mn);
 
        WARN_ON(!RB_EMPTY_ROOT(&per_mm->umem_tree.rb_root));
-       mmu_notifier_unregister_no_release(&per_mm->mn, per_mm->mm);
+
        put_pid(per_mm->tgid);
-       mmu_notifier_call_srcu(&per_mm->rcu, free_per_mm);
+       kfree(per_mm);
 }
 
-static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
-                                  struct ib_ucontext_per_mm *per_mm)
+static const struct mmu_notifier_ops ib_umem_notifiers = {
+       .release                    = ib_umem_notifier_release,
+       .invalidate_range_start     = ib_umem_notifier_invalidate_range_start,
+       .invalidate_range_end       = ib_umem_notifier_invalidate_range_end,
+       .alloc_notifier             = ib_umem_alloc_notifier,
+       .free_notifier              = ib_umem_free_notifier,
+};
+
+static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp)
 {
-       struct ib_ucontext *ctx = umem_odp->umem.context;
+       struct ib_ucontext_per_mm *per_mm;
+       struct mmu_notifier *mn;
        int ret;
 
        umem_odp->umem.is_odp = 1;
@@ -327,17 +252,13 @@ static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
                }
        }
 
-       mutex_lock(&ctx->per_mm_list_lock);
-       if (!per_mm) {
-               per_mm = get_per_mm(umem_odp);
-               if (IS_ERR(per_mm)) {
-                       ret = PTR_ERR(per_mm);
-                       goto out_unlock;
-               }
+       mn = mmu_notifier_get(&ib_umem_notifiers, umem_odp->umem.owning_mm);
+       if (IS_ERR(mn)) {
+               ret = PTR_ERR(mn);
+               goto out_dma_list;
        }
-       umem_odp->per_mm = per_mm;
-       per_mm->odp_mrs_count++;
-       mutex_unlock(&ctx->per_mm_list_lock);
+       umem_odp->per_mm = per_mm =
+               container_of(mn, struct ib_ucontext_per_mm, mn);
 
        mutex_init(&umem_odp->umem_mutex);
        init_completion(&umem_odp->notifier_completion);
@@ -352,8 +273,7 @@ static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
 
        return 0;
 
-out_unlock:
-       mutex_unlock(&ctx->per_mm_list_lock);
+out_dma_list:
        kvfree(umem_odp->dma_list);
 out_page_list:
        kvfree(umem_odp->page_list);
@@ -392,13 +312,13 @@ struct ib_umem_odp *ib_umem_odp_alloc_implicit(struct ib_udata *udata,
        if (!umem_odp)
                return ERR_PTR(-ENOMEM);
        umem = &umem_odp->umem;
-       umem->context = context;
+       umem->ibdev = context->device;
        umem->writable = ib_access_writable(access);
        umem->owning_mm = current->mm;
        umem_odp->is_implicit_odp = 1;
        umem_odp->page_shift = PAGE_SHIFT;
 
-       ret = ib_init_umem_odp(umem_odp, NULL);
+       ret = ib_init_umem_odp(umem_odp);
        if (ret) {
                kfree(umem_odp);
                return ERR_PTR(ret);
@@ -434,14 +354,14 @@ struct ib_umem_odp *ib_umem_odp_alloc_child(struct ib_umem_odp *root,
        if (!odp_data)
                return ERR_PTR(-ENOMEM);
        umem = &odp_data->umem;
-       umem->context    = root->umem.context;
+       umem->ibdev = root->umem.ibdev;
        umem->length     = size;
        umem->address    = addr;
        umem->writable   = root->umem.writable;
        umem->owning_mm  = root->umem.owning_mm;
        odp_data->page_shift = PAGE_SHIFT;
 
-       ret = ib_init_umem_odp(odp_data, root->per_mm);
+       ret = ib_init_umem_odp(odp_data);
        if (ret) {
                kfree(odp_data);
                return ERR_PTR(ret);
@@ -486,7 +406,7 @@ struct ib_umem_odp *ib_umem_odp_get(struct ib_udata *udata, unsigned long addr,
        if (!umem_odp)
                return ERR_PTR(-ENOMEM);
 
-       umem_odp->umem.context = context;
+       umem_odp->umem.ibdev = context->device;
        umem_odp->umem.length = size;
        umem_odp->umem.address = addr;
        umem_odp->umem.writable = ib_access_writable(access);
@@ -509,7 +429,7 @@ struct ib_umem_odp *ib_umem_odp_get(struct ib_udata *udata, unsigned long addr,
                up_read(&mm->mmap_sem);
        }
 
-       ret = ib_init_umem_odp(umem_odp, NULL);
+       ret = ib_init_umem_odp(umem_odp);
        if (ret)
                goto err_free;
        return umem_odp;
@@ -522,6 +442,8 @@ EXPORT_SYMBOL(ib_umem_odp_get);
 
 void ib_umem_odp_release(struct ib_umem_odp *umem_odp)
 {
+       struct ib_ucontext_per_mm *per_mm = umem_odp->per_mm;
+
        /*
         * Ensure that no more pages are mapped in the umem.
         *
@@ -531,11 +453,27 @@ void ib_umem_odp_release(struct ib_umem_odp *umem_odp)
        if (!umem_odp->is_implicit_odp) {
                ib_umem_odp_unmap_dma_pages(umem_odp, ib_umem_start(umem_odp),
                                            ib_umem_end(umem_odp));
-               remove_umem_from_per_mm(umem_odp);
                kvfree(umem_odp->dma_list);
                kvfree(umem_odp->page_list);
        }
-       put_per_mm(umem_odp);
+
+       down_write(&per_mm->umem_rwsem);
+       if (!umem_odp->is_implicit_odp) {
+               interval_tree_remove(&umem_odp->interval_tree,
+                                    &per_mm->umem_tree);
+               complete_all(&umem_odp->notifier_completion);
+       }
+       /*
+        * NOTE! mmu_notifier_unregister() can happen between a start/end
+        * callback, resulting in a missing end, and thus an unbalanced
+        * lock. This doesn't really matter to us since we are about to kfree
+        * the memory that holds the lock, however LOCKDEP doesn't like this.
+        * Thus we call the mmu_notifier_put under the rwsem and test the
+        * internal users count to reliably see if we are past this point.
+        */
+       mmu_notifier_put(&per_mm->mn);
+       up_write(&per_mm->umem_rwsem);
+
        mmdrop(umem_odp->umem.owning_mm);
        kfree(umem_odp);
 }
@@ -566,8 +504,7 @@ static int ib_umem_odp_map_dma_single_page(
                u64 access_mask,
                unsigned long current_seq)
 {
-       struct ib_ucontext *context = umem_odp->umem.context;
-       struct ib_device *dev = context->device;
+       struct ib_device *dev = umem_odp->umem.ibdev;
        dma_addr_t dma_addr;
        int remove_existing_mapping = 0;
        int ret = 0;
@@ -780,7 +717,7 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt,
 {
        int idx;
        u64 addr;
-       struct ib_device *dev = umem_odp->umem.context->device;
+       struct ib_device *dev = umem_odp->umem.ibdev;
 
        virt = max_t(u64, virt, ib_umem_start(umem_odp));
        bound = min_t(u64, bound, ib_umem_end(umem_odp));