[PATCH 6/20 v2] rdma/uverbs: Export XRC domains to user space

["Hefty, Sean" <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

Allow user space to create XRC domains.  Because xrcd's are
expected to be shared among multiple processes, we use inodes to
identify an xrcd.

Based on patches by Jack Morgenstein <jackm-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>

Signed-off-by: Sean Hefty <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/infiniband/core/uverbs.h      |   11 +
 drivers/infiniband/core/uverbs_cmd.c  |  319 +++++++++++++++++++++++++++++++++
 drivers/infiniband/core/uverbs_main.c |   17 ++
 drivers/infiniband/core/verbs.c       |    1 
 include/rdma/ib_user_verbs.h          |   19 ++
 include/rdma/ib_verbs.h               |    2 
 6 files changed, 368 insertions(+), 1 deletions(-)

diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h
index a078e56..461e2f3 100644
--- a/drivers/infiniband/core/uverbs.h
+++ b/drivers/infiniband/core/uverbs.h
@@ -76,6 +76,8 @@ struct ib_uverbs_device {
 	struct ib_device		       *ib_dev;
 	int					devnum;
 	struct cdev			        cdev;
+	struct rb_root				xrcd_tree;
+	struct mutex				xrcd_tree_mutex;
 };
 
 struct ib_uverbs_event_file {
@@ -120,6 +122,11 @@ struct ib_uevent_object {
 	u32			events_reported;
 };
 
+struct ib_uxrcd_object {
+	struct ib_uobject	uobject;
+	atomic_t		refcnt;
+};
+
 struct ib_uqp_object {
 	struct ib_uevent_object	uevent;
 	struct list_head 	mcast_list;
@@ -142,6 +149,7 @@ extern struct idr ib_uverbs_ah_idr;
 extern struct idr ib_uverbs_cq_idr;
 extern struct idr ib_uverbs_qp_idr;
 extern struct idr ib_uverbs_srq_idr;
+extern struct idr ib_uverbs_xrcd_idr;
 
 void idr_remove_uobj(struct idr *idp, struct ib_uobject *uobj);
 
@@ -161,6 +169,7 @@ void ib_uverbs_qp_event_handler(struct ib_event *event, void *context_ptr);
 void ib_uverbs_srq_event_handler(struct ib_event *event, void *context_ptr);
 void ib_uverbs_event_handler(struct ib_event_handler *handler,
 			     struct ib_event *event);
+void ib_uverbs_dealloc_xrcd(struct ib_uverbs_device *dev, struct ib_xrcd *xrcd);
 
 #define IB_UVERBS_DECLARE_CMD(name)					\
 	ssize_t ib_uverbs_##name(struct ib_uverbs_file *file,		\
@@ -195,5 +204,7 @@ IB_UVERBS_DECLARE_CMD(create_srq);
 IB_UVERBS_DECLARE_CMD(modify_srq);
 IB_UVERBS_DECLARE_CMD(query_srq);
 IB_UVERBS_DECLARE_CMD(destroy_srq);
+IB_UVERBS_DECLARE_CMD(open_xrcd);
+IB_UVERBS_DECLARE_CMD(close_xrcd);
 
 #endif /* UVERBS_H */
diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 48d21d0..7b2b3b8 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -47,6 +47,7 @@ static struct lock_class_key cq_lock_key;
 static struct lock_class_key qp_lock_key;
 static struct lock_class_key ah_lock_key;
 static struct lock_class_key srq_lock_key;
+static struct lock_class_key xrcd_lock_key;
 
 #define INIT_UDATA(udata, ibuf, obuf, ilen, olen)			\
 	do {								\
@@ -255,6 +256,18 @@ static void put_srq_read(struct ib_srq *srq)
 	put_uobj_read(srq->uobject);
 }
 
+static struct ib_xrcd *idr_read_xrcd(int xrcd_handle, struct ib_ucontext *context,
+				     struct ib_uobject **uobj)
+{
+	*uobj = idr_read_uobj(&ib_uverbs_xrcd_idr, xrcd_handle, context, 0);
+	return *uobj ? (*uobj)->object : NULL;
+}
+
+static void put_xrcd_read(struct ib_uobject *uobj)
+{
+	put_uobj_read(uobj);
+}
+
 ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
 			      const char __user *buf,
 			      int in_len, int out_len)
@@ -298,6 +311,7 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
 	INIT_LIST_HEAD(&ucontext->qp_list);
 	INIT_LIST_HEAD(&ucontext->srq_list);
 	INIT_LIST_HEAD(&ucontext->ah_list);
+	INIT_LIST_HEAD(&ucontext->xrcd_list);
 	ucontext->closing = 0;
 
 	resp.num_comp_vectors = file->device->num_comp_vectors;
@@ -579,6 +593,311 @@ ssize_t ib_uverbs_dealloc_pd(struct ib_uverbs_file *file,
 	return in_len;
 }
 
+struct xrcd_table_entry {
+	struct rb_node  node;
+	struct ib_xrcd *xrcd;
+	struct inode   *inode;
+};
+
+static int xrcd_table_insert(struct ib_uverbs_device *dev,
+			    struct inode *inode,
+			    struct ib_xrcd *xrcd)
+{
+	struct xrcd_table_entry *entry, *scan;
+	struct rb_node **p = &dev->xrcd_tree.rb_node;
+	struct rb_node *parent = NULL;
+
+	entry = kmalloc(sizeof *entry, GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->xrcd  = xrcd;
+	entry->inode = inode;
+
+	while (*p) {
+		parent = *p;
+		scan = rb_entry(parent, struct xrcd_table_entry, node);
+
+		if (inode < scan->inode) {
+			p = &(*p)->rb_left;
+		} else if (inode > scan->inode) {
+			p = &(*p)->rb_right;
+		} else {
+			kfree(entry);
+			return -EEXIST;
+		}
+	}
+
+	rb_link_node(&entry->node, parent, p);
+	rb_insert_color(&entry->node, &dev->xrcd_tree);
+	igrab(inode);
+	return 0;
+}
+
+static struct xrcd_table_entry *xrcd_table_search(struct ib_uverbs_device *dev,
+						  struct inode *inode)
+{
+	struct xrcd_table_entry *entry;
+	struct rb_node *p = dev->xrcd_tree.rb_node;
+
+	while (p) {
+		entry = rb_entry(p, struct xrcd_table_entry, node);
+
+		if (inode < entry->inode)
+			p = p->rb_left;
+		else if (inode > entry->inode)
+			p = p->rb_right;
+		else
+			return entry;
+	}
+
+	return NULL;
+}
+
+static struct ib_xrcd *find_xrcd(struct ib_uverbs_device *dev, struct inode *inode)
+{
+	struct xrcd_table_entry *entry;
+
+	entry = xrcd_table_search(dev, inode);
+	if (!entry)
+		return NULL;
+
+	return entry->xrcd;
+}
+
+
+static void xrcd_table_delete(struct ib_uverbs_device *dev,
+			      struct inode *inode)
+{
+	struct xrcd_table_entry *entry;
+
+	entry = xrcd_table_search(dev, inode);
+	if (entry) {
+		iput(inode);
+		rb_erase(&entry->node, &dev->xrcd_tree);
+		kfree(entry);
+	}
+}
+
+ssize_t ib_uverbs_open_xrcd(struct ib_uverbs_file *file,
+			    const char __user *buf, int in_len,
+			    int out_len)
+{
+	struct ib_uverbs_open_xrcd	cmd;
+	struct ib_uverbs_open_xrcd_resp	resp;
+	struct ib_udata			udata;
+	struct ib_uxrcd_object         *obj;
+	struct ib_xrcd                 *xrcd = NULL;
+	struct file                    *f = NULL;
+	struct inode                   *inode = NULL;
+	int				ret = 0;
+	int				new_xrcd = 0;
+
+	if (out_len < sizeof resp)
+		return -ENOSPC;
+
+	if (copy_from_user(&cmd, buf, sizeof cmd))
+		return -EFAULT;
+
+	INIT_UDATA(&udata, buf + sizeof cmd,
+		   (unsigned long) cmd.response + sizeof resp,
+		   in_len - sizeof cmd, out_len - sizeof  resp);
+
+	mutex_lock(&file->device->xrcd_tree_mutex);
+
+	if (cmd.fd != -1) {
+		/* search for file descriptor */
+		f = fget(cmd.fd);
+		if (!f) {
+			ret = -EBADF;
+			goto err_tree_mutex_unlock;
+		}
+
+		inode = f->f_dentry->d_inode;
+		if (!inode) {
+			ret = -EBADF;
+			goto err_tree_mutex_unlock;
+		}
+
+		xrcd = find_xrcd(file->device, inode);
+		if (!xrcd && !(cmd.oflags & O_CREAT)) {
+			/* no file descriptor. Need CREATE flag */
+			ret = -EAGAIN;
+			goto err_tree_mutex_unlock;
+		}
+
+		if (xrcd && cmd.oflags & O_EXCL) {
+			ret = -EINVAL;
+			goto err_tree_mutex_unlock;
+		}
+	}
+
+	obj = kmalloc(sizeof *obj, GFP_KERNEL);
+	if (!obj) {
+		ret = -ENOMEM;
+		goto err_tree_mutex_unlock;
+	}
+
+	init_uobj(&obj->uobject, 0, file->ucontext, &xrcd_lock_key);
+
+	down_write(&obj->uobject.mutex);
+
+	if (!xrcd) {
+		xrcd = file->device->ib_dev->alloc_xrcd(file->device->ib_dev,
+							file->ucontext, &udata);
+		if (IS_ERR(xrcd)) {
+			ret = PTR_ERR(xrcd);
+			goto err;
+		}
+
+		xrcd->inode   = inode;
+		xrcd->device  = file->device->ib_dev;
+		atomic_set(&xrcd->usecnt, 0);
+		mutex_init(&xrcd->tgt_qp_mutex);
+		INIT_LIST_HEAD(&xrcd->tgt_qp_list);
+		new_xrcd = 1;
+	}
+
+	atomic_set(&obj->refcnt, 0);
+	obj->uobject.object = xrcd;
+	ret = idr_add_uobj(&ib_uverbs_xrcd_idr, &obj->uobject);
+	if (ret)
+		goto err_idr;
+
+	memset(&resp, 0, sizeof resp);
+	resp.xrcd_handle = obj->uobject.id;
+
+	if (inode) {
+		if (new_xrcd) {
+			/* create new inode/xrcd table entry */
+			ret = xrcd_table_insert(file->device, inode, xrcd);
+			if (ret)
+				goto err_insert_xrcd;
+		}
+		atomic_inc(&xrcd->usecnt);
+	}
+
+	if (copy_to_user((void __user *) (unsigned long) cmd.response,
+			 &resp, sizeof resp)) {
+		ret = -EFAULT;
+		goto err_copy;
+	}
+
+	if (f)
+		fput(f);
+
+	mutex_lock(&file->mutex);
+	list_add_tail(&obj->uobject.list, &file->ucontext->xrcd_list);
+	mutex_unlock(&file->mutex);
+
+	obj->uobject.live = 1;
+	up_write(&obj->uobject.mutex);
+
+	mutex_unlock(&file->device->xrcd_tree_mutex);
+	return in_len;
+
+err_copy:
+	if (inode) {
+		if (new_xrcd)
+			xrcd_table_delete(file->device, inode);
+		atomic_dec(&xrcd->usecnt);
+	}
+
+err_insert_xrcd:
+	idr_remove_uobj(&ib_uverbs_xrcd_idr, &obj->uobject);
+
+err_idr:
+	ib_dealloc_xrcd(xrcd);
+
+err:
+	put_uobj_write(&obj->uobject);
+
+err_tree_mutex_unlock:
+	if (f)
+		fput(f);
+
+	mutex_unlock(&file->device->xrcd_tree_mutex);
+
+	return ret;
+}
+
+ssize_t ib_uverbs_close_xrcd(struct ib_uverbs_file *file,
+			     const char __user *buf, int in_len,
+			     int out_len)
+{
+	struct ib_uverbs_close_xrcd cmd;
+	struct ib_uobject           *uobj;
+	struct ib_xrcd              *xrcd = NULL;
+	struct inode                *inode = NULL;
+	struct ib_uxrcd_object      *obj;
+	int                         live;
+	int                         ret = 0;
+
+	if (copy_from_user(&cmd, buf, sizeof cmd))
+		return -EFAULT;
+
+	mutex_lock(&file->device->xrcd_tree_mutex);
+	uobj = idr_write_uobj(&ib_uverbs_xrcd_idr, cmd.xrcd_handle, file->ucontext);
+	if (!uobj) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	xrcd  = uobj->object;
+	inode = xrcd->inode;
+	obj   = container_of(uobj, struct ib_uxrcd_object, uobject);
+	if (atomic_read(&obj->refcnt)) {
+		put_uobj_write(uobj);
+		ret = -EBUSY;
+		goto out;
+	}
+
+	if (!inode || atomic_dec_and_test(&xrcd->usecnt)) {
+		ret = ib_dealloc_xrcd(uobj->object);
+		if (!ret)
+			uobj->live = 0;
+	}
+
+	live = uobj->live;
+	if (inode && ret)
+		atomic_inc(&xrcd->usecnt);
+
+	put_uobj_write(uobj);
+
+	if (ret)
+		goto out;
+
+	if (inode && !live)
+		xrcd_table_delete(file->device, inode);
+
+	idr_remove_uobj(&ib_uverbs_xrcd_idr, uobj);
+	mutex_lock(&file->mutex);
+	list_del(&uobj->list);
+	mutex_unlock(&file->mutex);
+
+	put_uobj(uobj);
+	ret = in_len;
+
+out:
+	mutex_unlock(&file->device->xrcd_tree_mutex);
+	return ret;
+}
+
+void ib_uverbs_dealloc_xrcd(struct ib_uverbs_device *dev,
+			    struct ib_xrcd *xrcd)
+{
+	struct inode *inode;
+
+	inode = xrcd->inode;
+	if (inode && !atomic_dec_and_test(&xrcd->usecnt))
+		return;
+
+	ib_dealloc_xrcd(xrcd);
+
+	if (inode)
+		xrcd_table_delete(dev, inode);
+}
+
 ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
 			 const char __user *buf, int in_len,
 			 int out_len)
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 56898b6..bb9dcea 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -72,6 +72,7 @@ DEFINE_IDR(ib_uverbs_ah_idr);
 DEFINE_IDR(ib_uverbs_cq_idr);
 DEFINE_IDR(ib_uverbs_qp_idr);
 DEFINE_IDR(ib_uverbs_srq_idr);
+DEFINE_IDR(ib_uverbs_xrcd_idr);
 
 static DEFINE_SPINLOCK(map_lock);
 static DECLARE_BITMAP(dev_map, IB_UVERBS_MAX_DEVICES);
@@ -107,6 +108,8 @@ static ssize_t (*uverbs_cmd_table[])(struct ib_uverbs_file *file,
 	[IB_USER_VERBS_CMD_MODIFY_SRQ]		= ib_uverbs_modify_srq,
 	[IB_USER_VERBS_CMD_QUERY_SRQ]		= ib_uverbs_query_srq,
 	[IB_USER_VERBS_CMD_DESTROY_SRQ]		= ib_uverbs_destroy_srq,
+	[IB_USER_VERBS_CMD_OPEN_XRCD]		= ib_uverbs_open_xrcd,
+	[IB_USER_VERBS_CMD_CLOSE_XRCD]		= ib_uverbs_close_xrcd,
 };
 
 static void ib_uverbs_add_one(struct ib_device *device);
@@ -241,6 +244,18 @@ static int ib_uverbs_cleanup_ucontext(struct ib_uverbs_file *file,
 		kfree(uobj);
 	}
 
+	mutex_lock(&file->device->xrcd_tree_mutex);
+	list_for_each_entry_safe(uobj, tmp, &context->xrcd_list, list) {
+		struct ib_xrcd *xrcd = uobj->object;
+		struct ib_uxrcd_object *uxrcd =
+			container_of(uobj, struct ib_uxrcd_object, uobject);
+
+		idr_remove_uobj(&ib_uverbs_xrcd_idr, uobj);
+		ib_uverbs_dealloc_xrcd(file->device, xrcd);
+		kfree(uxrcd);
+	}
+	mutex_unlock(&file->device->xrcd_tree_mutex);
+
 	list_for_each_entry_safe(uobj, tmp, &context->pd_list, list) {
 		struct ib_pd *pd = uobj->object;
 
@@ -741,6 +756,8 @@ static void ib_uverbs_add_one(struct ib_device *device)
 
 	kref_init(&uverbs_dev->ref);
 	init_completion(&uverbs_dev->comp);
+	uverbs_dev->xrcd_tree = RB_ROOT;
+	mutex_init(&uverbs_dev->xrcd_tree_mutex);
 
 	spin_lock(&map_lock);
 	devnum = find_first_zero_bit(dev_map, IB_UVERBS_MAX_DEVICES);
diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
index a0e515b..6d034b6 100644
--- a/drivers/infiniband/core/verbs.c
+++ b/drivers/infiniband/core/verbs.c
@@ -1094,6 +1094,7 @@ struct ib_xrcd *ib_alloc_xrcd(struct ib_device *device)
 	xrcd = device->alloc_xrcd(device, NULL, NULL);
 	if (!IS_ERR(xrcd)) {
 		xrcd->device = device;
+		xrcd->inode = NULL;
 		atomic_set(&xrcd->usecnt, 0);
 		mutex_init(&xrcd->tgt_qp_mutex);
 		INIT_LIST_HEAD(&xrcd->tgt_qp_list);
diff --git a/include/rdma/ib_user_verbs.h b/include/rdma/ib_user_verbs.h
index fe5b051..b5cb63f 100644
--- a/include/rdma/ib_user_verbs.h
+++ b/include/rdma/ib_user_verbs.h
@@ -81,7 +81,9 @@ enum {
 	IB_USER_VERBS_CMD_MODIFY_SRQ,
 	IB_USER_VERBS_CMD_QUERY_SRQ,
 	IB_USER_VERBS_CMD_DESTROY_SRQ,
-	IB_USER_VERBS_CMD_POST_SRQ_RECV
+	IB_USER_VERBS_CMD_POST_SRQ_RECV,
+	IB_USER_VERBS_CMD_OPEN_XRCD,
+	IB_USER_VERBS_CMD_CLOSE_XRCD
 };
 
 /*
@@ -222,6 +224,21 @@ struct ib_uverbs_dealloc_pd {
 	__u32 pd_handle;
 };
 
+struct ib_uverbs_open_xrcd {
+	__u64 response;
+	__u32 fd;
+	__u32 oflags;
+	__u64 driver_data[0];
+};
+
+struct ib_uverbs_open_xrcd_resp {
+	__u32 xrcd_handle;
+};
+
+struct ib_uverbs_close_xrcd {
+	__u32 xrcd_handle;
+};
+
 struct ib_uverbs_reg_mr {
 	__u64 response;
 	__u64 start;
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 45ed04b..a779fa0 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -850,6 +850,7 @@ struct ib_ucontext {
 	struct list_head	qp_list;
 	struct list_head	srq_list;
 	struct list_head	ah_list;
+	struct list_head	xrcd_list;
 	int			closing;
 };
 
@@ -880,6 +881,7 @@ struct ib_pd {
 struct ib_xrcd {
 	struct ib_device       *device;
 	atomic_t          	usecnt; /* count all exposed resources */
+	struct inode	       *inode;
 
 	struct mutex		tgt_qp_mutex;
 	struct list_head	tgt_qp_list;


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