[PATCH 01/15] drm/i915: really simple gemfs

[Matthew Auld <matthew.auld@intel.com>]

Not a fully blown gemfs, just our very own tmpfs kernel mount. Doing so
moves us away from the shmemfs shm_mnt, and gives us the much needed
flexibility to do things like set our own mount options, namely huge=
which should allow us to enable the use of transparent-huge-pages for
our shmem backed objects.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/Makefile                    |   1 +
 drivers/gpu/drm/i915/i915_drv.h                  |  13 +++
 drivers/gpu/drm/i915/i915_gem.c                  |  30 ++++++-
 drivers/gpu/drm/i915/i915_gemfs.c                | 105 +++++++++++++++++++++++
 drivers/gpu/drm/i915/selftests/mock_gem_device.c |  12 ++-
 5 files changed, 159 insertions(+), 2 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/i915_gemfs.c

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 16dccf550412..1a70af7d51ec 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -46,6 +46,7 @@ i915-y += i915_cmd_parser.o \
 	  i915_gem_tiling.o \
 	  i915_gem_timeline.o \
 	  i915_gem_userptr.o \
+	  i915_gemfs.o \
 	  i915_trace_points.o \
 	  i915_vma.o \
 	  intel_breadcrumbs.o \
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d2a57493ac2e..ca3196e2566f 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2227,6 +2227,9 @@ struct drm_i915_private {
 	DECLARE_HASHTABLE(mm_structs, 7);
 	struct mutex mm_lock;
 
+	/* Our tmpfs instance used for shmem backed objects */
+	struct vfsmount *gemfs_mnt;
+
 	/* The hw wants to have a stable context identifier for the lifetime
 	 * of the context (for OA, PASID, faults, etc). This is limited
 	 * in execlists to 21 bits.
@@ -4169,4 +4172,14 @@ static inline bool i915_gem_object_is_coherent(struct drm_i915_gem_object *obj)
 		HAS_LLC(to_i915(obj->base.dev)));
 }
 
+/* i915_gemfs.c */
+struct vfsmount *i915_gemfs_create(void);
+
+void i915_gemfs_destroy(struct vfsmount *gemfs_mnt);
+
+struct file *i915_gemfs_file_setup(struct vfsmount *gemfs_mnt,
+				   const char *name, size_t size);
+
+int i915_gemfs_unlink(struct file *filp);
+
 #endif
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7ab47a84671f..30f9af590969 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4245,6 +4245,24 @@ static const struct drm_i915_gem_object_ops i915_gem_object_ops = {
 	.pwrite = i915_gem_object_pwrite_gtt,
 };
 
+static int i915_drm_gem_object_init(struct drm_device *dev,
+				    struct drm_gem_object *obj,
+				    size_t size)
+{
+	struct drm_i915_private *i915 = to_i915(dev);
+	struct file *filp;
+
+	drm_gem_private_object_init(dev, obj, size);
+
+	filp = i915_gemfs_file_setup(i915->gemfs_mnt, "i915 mm object", size);
+	if (IS_ERR(filp))
+		return PTR_ERR(filp);
+
+	obj->filp = filp;
+
+	return 0;
+}
+
 struct drm_i915_gem_object *
 i915_gem_object_create(struct drm_i915_private *dev_priv, u64 size)
 {
@@ -4268,7 +4286,7 @@ i915_gem_object_create(struct drm_i915_private *dev_priv, u64 size)
 	if (obj == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	ret = drm_gem_object_init(&dev_priv->drm, &obj->base, size);
+	ret = i915_drm_gem_object_init(&dev_priv->drm, &obj->base, size);
 	if (ret)
 		goto fail;
 
@@ -4383,6 +4401,9 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915,
 			drm_prime_gem_destroy(&obj->base, NULL);
 
 		reservation_object_fini(&obj->__builtin_resv);
+
+		if (obj->base.filp)
+			i915_gemfs_unlink(obj->base.filp);
 		drm_gem_object_release(&obj->base);
 		i915_gem_info_remove_obj(i915, obj->base.size);
 
@@ -4843,6 +4864,10 @@ i915_gem_load_init(struct drm_i915_private *dev_priv)
 {
 	int err = -ENOMEM;
 
+	dev_priv->gemfs_mnt = i915_gemfs_create();
+	if (IS_ERR(dev_priv->gemfs_mnt))
+		return PTR_ERR(dev_priv->gemfs_mnt);
+
 	dev_priv->objects = KMEM_CACHE(drm_i915_gem_object, SLAB_HWCACHE_ALIGN);
 	if (!dev_priv->objects)
 		goto err_out;
@@ -4908,6 +4933,7 @@ i915_gem_load_init(struct drm_i915_private *dev_priv)
 err_objects:
 	kmem_cache_destroy(dev_priv->objects);
 err_out:
+	i915_gemfs_destroy(dev_priv->gemfs_mnt);
 	return err;
 }
 
@@ -4930,6 +4956,8 @@ void i915_gem_load_cleanup(struct drm_i915_private *dev_priv)
 
 	/* And ensure that our DESTROY_BY_RCU slabs are truly destroyed */
 	rcu_barrier();
+
+	i915_gemfs_destroy(dev_priv->gemfs_mnt);
 }
 
 int i915_gem_freeze(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/i915_gemfs.c b/drivers/gpu/drm/i915/i915_gemfs.c
new file mode 100644
index 000000000000..e1b2af1d9946
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_gemfs.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright © 2017 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+
+static const struct dentry_operations anon_ops = {
+	.d_dname = simple_dname
+};
+
+struct vfsmount *i915_gemfs_create(void)
+{
+	struct file_system_type *type;
+	struct vfsmount *gemfs_mnt;
+
+	type = get_fs_type("tmpfs");
+	if (!type)
+		return ERR_PTR(-EINVAL);
+
+	gemfs_mnt = kern_mount(type);
+
+	return gemfs_mnt;
+}
+
+void i915_gemfs_destroy(struct vfsmount *gemfs_mnt)
+{
+	kern_unmount(gemfs_mnt);
+}
+
+struct file *i915_gemfs_file_setup(struct vfsmount *gemfs_mnt,
+				   const char *name, size_t size)
+{
+	struct super_block *sb = gemfs_mnt->mnt_sb;
+	struct inode *dir = d_inode(sb->s_root);
+	struct inode *inode;
+	struct path path;
+	struct qstr this;
+	struct file *res;
+	int ret;
+
+	if (size < 0 || size > MAX_LFS_FILESIZE)
+		return ERR_PTR(-EINVAL);
+
+	this.name = name;
+	this.len = strlen(name);
+	this.hash = 0;
+
+	path.mnt = mntget(gemfs_mnt);
+	path.dentry = d_alloc_pseudo(sb, &this);
+	if (!path.dentry) {
+		res = ERR_PTR(-ENOMEM);
+		goto put_path;
+	}
+	d_set_d_op(path.dentry, &anon_ops);
+
+	ret = dir->i_op->create(dir, path.dentry, S_IFREG | S_IRWXUGO, false);
+	if (ret) {
+		res = ERR_PTR(ret);
+		goto put_path;
+	}
+
+	inode = d_inode(path.dentry);
+	inode->i_size = size;
+
+	res = alloc_file(&path, FMODE_WRITE | FMODE_READ, inode->i_fop);
+	if (IS_ERR(res))
+		goto unlink;
+
+	return res;
+
+unlink:
+	dir->i_op->unlink(dir, path.dentry);
+put_path:
+	path_put(&path);
+	return res;
+}
+
+int i915_gemfs_unlink(struct file *filp)
+{
+	struct inode *dir = d_inode(filp->f_inode->i_sb->s_root);
+
+	return dir->i_op->unlink(dir, filp->f_path.dentry);
+}
diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
index 627e2aa09766..7f038ea15ef5 100644
--- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
+++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
@@ -80,6 +80,8 @@ static void mock_device_release(struct drm_device *dev)
 	kmem_cache_destroy(i915->vmas);
 	kmem_cache_destroy(i915->objects);
 
+	i915_gemfs_destroy(i915->gemfs_mnt);
+
 	drm_dev_fini(&i915->drm);
 	put_device(&i915->drm.pdev->dev);
 }
@@ -167,9 +169,15 @@ struct drm_i915_private *mock_gem_device(void)
 
 	i915->gt.awake = true;
 
+	i915->gemfs_mnt = i915_gemfs_create();
+	if (IS_ERR(i915->gemfs_mnt)) {
+		err = PTR_ERR(i915->gemfs_mnt);
+		goto err_wq;
+	}
+
 	i915->objects = KMEM_CACHE(mock_object, SLAB_HWCACHE_ALIGN);
 	if (!i915->objects)
-		goto err_wq;
+		goto err_gemfs;
 
 	i915->vmas = KMEM_CACHE(i915_vma, SLAB_HWCACHE_ALIGN);
 	if (!i915->vmas)
@@ -227,6 +235,8 @@ struct drm_i915_private *mock_gem_device(void)
 	kmem_cache_destroy(i915->vmas);
 err_objects:
 	kmem_cache_destroy(i915->objects);
+err_gemfs:
+	i915_gemfs_destroy(i915->gemfs_mnt);
 err_wq:
 	destroy_workqueue(i915->wq);
 put_device:
-- 
2.9.4

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