RDMA/core: Move core content from ib_uverbs to ib_core

Move functionality that is called by the driver, which is
related to umap, to a new file that will be linked in ib_core.
This is a first step in later enabling ib_uverbs to be optional.
vm_ops is now initialized in ib_uverbs_mmap instead of
priv_init to avoid having to move all the rdma_umap functions
as well.

Link: https://lore.kernel.org/r/20191030094417.16866-2-michal.kalderon@marvell.com
Suggested-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Ariel Elior <ariel.elior@marvell.com>
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/drivers/infiniband/core/ib_core_uverbs.c b/drivers/infiniband/core/ib_core_uverbs.c
new file mode 100644
index 000000000000..b74d2a2fb342
--- /dev/null
+++ b/drivers/infiniband/core/ib_core_uverbs.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
+ * Copyright 2018-2019 Amazon.com, Inc. or its affiliates. All rights reserved.
+ * Copyright 2019 Marvell. All rights reserved.
+ */
+#include <linux/xarray.h>
+#include "uverbs.h"
+#include "core_priv.h"
+
+/*
+ * Each time we map IO memory into user space this keeps track of the mapping.
+ * When the device is hot-unplugged we 'zap' the mmaps in user space to point
+ * to the zero page and allow the hot unplug to proceed.
+ *
+ * This is necessary for cases like PCI physical hot unplug as the actual BAR
+ * memory may vanish after this and access to it from userspace could MCE.
+ *
+ * RDMA drivers supporting disassociation must have their user space designed
+ * to cope in some way with their IO pages going to the zero page.
+ */
+void rdma_umap_priv_init(struct rdma_umap_priv *priv,
+			 struct vm_area_struct *vma)
+{
+	struct ib_uverbs_file *ufile = vma->vm_file->private_data;
+
+	priv->vma = vma;
+	vma->vm_private_data = priv;
+	/* vm_ops is setup in ib_uverbs_mmap() to avoid module dependencies */
+
+	mutex_lock(&ufile->umap_lock);
+	list_add(&priv->list, &ufile->umaps);
+	mutex_unlock(&ufile->umap_lock);
+}
+EXPORT_SYMBOL(rdma_umap_priv_init);
+
+/*
+ * Map IO memory into a process. This is to be called by drivers as part of
+ * their mmap() functions if they wish to send something like PCI-E BAR memory
+ * to userspace.
+ */
+int rdma_user_mmap_io(struct ib_ucontext *ucontext, struct vm_area_struct *vma,
+		      unsigned long pfn, unsigned long size, pgprot_t prot)
+{
+	struct ib_uverbs_file *ufile = ucontext->ufile;
+	struct rdma_umap_priv *priv;
+
+	if (!(vma->vm_flags & VM_SHARED))
+		return -EINVAL;
+
+	if (vma->vm_end - vma->vm_start != size)
+		return -EINVAL;
+
+	/* Driver is using this wrong, must be called by ib_uverbs_mmap */
+	if (WARN_ON(!vma->vm_file ||
+		    vma->vm_file->private_data != ufile))
+		return -EINVAL;
+	lockdep_assert_held(&ufile->device->disassociate_srcu);
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	vma->vm_page_prot = prot;
+	if (io_remap_pfn_range(vma, vma->vm_start, pfn, size, prot)) {
+		kfree(priv);
+		return -EAGAIN;
+	}
+
+	rdma_umap_priv_init(priv, vma);
+	return 0;
+}
+EXPORT_SYMBOL(rdma_user_mmap_io);