[linux-2.6-block.git] / drivers / dma-buf / udmabuf.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/cred.h>
#include <linux/device.h>
#include <linux/dma-buf.h>
#include <linux/highmem.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/memfd.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/shmem_fs.h>
#include <linux/slab.h>
#include <linux/udmabuf.h>

static const u32    list_limit = 1024;  /* udmabuf_create_list->count limit */
static const size_t size_limit_mb = 64; /* total dmabuf size, in megabytes  */

struct udmabuf {
	pgoff_t pagecount;
	struct page **pages;
};

static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf)
{
	struct vm_area_struct *vma = vmf->vma;
	struct udmabuf *ubuf = vma->vm_private_data;

	vmf->page = ubuf->pages[vmf->pgoff];
	get_page(vmf->page);
	return 0;
}

static const struct vm_operations_struct udmabuf_vm_ops = {
	.fault = udmabuf_vm_fault,
};

static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma)
{
	struct udmabuf *ubuf = buf->priv;

	if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
		return -EINVAL;

	vma->vm_ops = &udmabuf_vm_ops;
	vma->vm_private_data = ubuf;
	return 0;
}

static struct sg_table *map_udmabuf(struct dma_buf_attachment *at,
				    enum dma_data_direction direction)
{
	struct udmabuf *ubuf = at->dmabuf->priv;
	struct sg_table *sg;
	int ret;

	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
	if (!sg)
		return ERR_PTR(-ENOMEM);
	ret = sg_alloc_table_from_pages(sg, ubuf->pages, ubuf->pagecount,
					0, ubuf->pagecount << PAGE_SHIFT,
					GFP_KERNEL);
	if (ret < 0)
		goto err;
	if (!dma_map_sg(at->dev, sg->sgl, sg->nents, direction)) {
		ret = -EINVAL;
		goto err;
	}
	return sg;

err:
	sg_free_table(sg);
	kfree(sg);
	return ERR_PTR(ret);
}

static void unmap_udmabuf(struct dma_buf_attachment *at,
			  struct sg_table *sg,
			  enum dma_data_direction direction)
{
	dma_unmap_sg(at->dev, sg->sgl, sg->nents, direction);
	sg_free_table(sg);
	kfree(sg);
}

static void release_udmabuf(struct dma_buf *buf)
{
	struct udmabuf *ubuf = buf->priv;
	pgoff_t pg;

	for (pg = 0; pg < ubuf->pagecount; pg++)
		put_page(ubuf->pages[pg]);
	kfree(ubuf->pages);
	kfree(ubuf);
}

static void *kmap_udmabuf(struct dma_buf *buf, unsigned long page_num)
{
	struct udmabuf *ubuf = buf->priv;
	struct page *page = ubuf->pages[page_num];

	return kmap(page);
}

static void kunmap_udmabuf(struct dma_buf *buf, unsigned long page_num,
			   void *vaddr)
{
	kunmap(vaddr);
}

static const struct dma_buf_ops udmabuf_ops = {
	.map_dma_buf	  = map_udmabuf,
	.unmap_dma_buf	  = unmap_udmabuf,
	.release	  = release_udmabuf,
	.map		  = kmap_udmabuf,
	.unmap		  = kunmap_udmabuf,
	.mmap		  = mmap_udmabuf,
};

#define SEALS_WANTED (F_SEAL_SHRINK)
#define SEALS_DENIED (F_SEAL_WRITE)

static long udmabuf_create(const struct udmabuf_create_list *head,
			   const struct udmabuf_create_item *list)
{
	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
	struct file *memfd = NULL;
	struct udmabuf *ubuf;
	struct dma_buf *buf;
	pgoff_t pgoff, pgcnt, pgidx, pgbuf = 0, pglimit;
	struct page *page;
	int seals, ret = -EINVAL;
	u32 i, flags;

	ubuf = kzalloc(sizeof(*ubuf), GFP_KERNEL);
	if (!ubuf)
		return -ENOMEM;

	pglimit = (size_limit_mb * 1024 * 1024) >> PAGE_SHIFT;
	for (i = 0; i < head->count; i++) {
		if (!IS_ALIGNED(list[i].offset, PAGE_SIZE))
			goto err;
		if (!IS_ALIGNED(list[i].size, PAGE_SIZE))
			goto err;
		ubuf->pagecount += list[i].size >> PAGE_SHIFT;
		if (ubuf->pagecount > pglimit)
			goto err;
	}
	ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(*ubuf->pages),
				    GFP_KERNEL);
	if (!ubuf->pages) {
		ret = -ENOMEM;
		goto err;
	}

	pgbuf = 0;
	for (i = 0; i < head->count; i++) {
		ret = -EBADFD;
		memfd = fget(list[i].memfd);
		if (!memfd)
			goto err;
		if (!shmem_mapping(file_inode(memfd)->i_mapping))
			goto err;
		seals = memfd_fcntl(memfd, F_GET_SEALS, 0);
		if (seals == -EINVAL)
			goto err;
		ret = -EINVAL;
		if ((seals & SEALS_WANTED) != SEALS_WANTED ||
		    (seals & SEALS_DENIED) != 0)
			goto err;
		pgoff = list[i].offset >> PAGE_SHIFT;
		pgcnt = list[i].size   >> PAGE_SHIFT;
		for (pgidx = 0; pgidx < pgcnt; pgidx++) {
			page = shmem_read_mapping_page(
				file_inode(memfd)->i_mapping, pgoff + pgidx);
			if (IS_ERR(page)) {
				ret = PTR_ERR(page);
				goto err;
			}
			ubuf->pages[pgbuf++] = page;
		}
		fput(memfd);
		memfd = NULL;
	}

	exp_info.ops  = &udmabuf_ops;
	exp_info.size = ubuf->pagecount << PAGE_SHIFT;
	exp_info.priv = ubuf;
	exp_info.flags = O_RDWR;

	buf = dma_buf_export(&exp_info);
	if (IS_ERR(buf)) {
		ret = PTR_ERR(buf);
		goto err;
	}

	flags = 0;
	if (head->flags & UDMABUF_FLAGS_CLOEXEC)
		flags |= O_CLOEXEC;
	return dma_buf_fd(buf, flags);

err:
	while (pgbuf > 0)
		put_page(ubuf->pages[--pgbuf]);
	if (memfd)
		fput(memfd);
	kfree(ubuf->pages);
	kfree(ubuf);
	return ret;
}

static long udmabuf_ioctl_create(struct file *filp, unsigned long arg)
{
	struct udmabuf_create create;
	struct udmabuf_create_list head;
	struct udmabuf_create_item list;

	if (copy_from_user(&create, (void __user *)arg,
			   sizeof(create)))
		return -EFAULT;

	head.flags  = create.flags;
	head.count  = 1;
	list.memfd  = create.memfd;
	list.offset = create.offset;
	list.size   = create.size;

	return udmabuf_create(&head, &list);
}

static long udmabuf_ioctl_create_list(struct file *filp, unsigned long arg)
{
	struct udmabuf_create_list head;
	struct udmabuf_create_item *list;
	int ret = -EINVAL;
	u32 lsize;

	if (copy_from_user(&head, (void __user *)arg, sizeof(head)))
		return -EFAULT;
	if (head.count > list_limit)
		return -EINVAL;
	lsize = sizeof(struct udmabuf_create_item) * head.count;
	list = memdup_user((void __user *)(arg + sizeof(head)), lsize);
	if (IS_ERR(list))
		return PTR_ERR(list);

	ret = udmabuf_create(&head, list);
	kfree(list);
	return ret;
}

static long udmabuf_ioctl(struct file *filp, unsigned int ioctl,
			  unsigned long arg)
{
	long ret;

	switch (ioctl) {
	case UDMABUF_CREATE:
		ret = udmabuf_ioctl_create(filp, arg);
		break;
	case UDMABUF_CREATE_LIST:
		ret = udmabuf_ioctl_create_list(filp, arg);
		break;
	default:
		ret = -ENOTTY;
		break;
	}
	return ret;
}

static const struct file_operations udmabuf_fops = {
	.owner		= THIS_MODULE,
	.unlocked_ioctl = udmabuf_ioctl,
};

static struct miscdevice udmabuf_misc = {
	.minor          = MISC_DYNAMIC_MINOR,
	.name           = "udmabuf",
	.fops           = &udmabuf_fops,
};

static int __init udmabuf_dev_init(void)
{
	return misc_register(&udmabuf_misc);
}

static void __exit udmabuf_dev_exit(void)
{
	misc_deregister(&udmabuf_misc);
}

module_init(udmabuf_dev_init)
module_exit(udmabuf_dev_exit)

MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
fbb0de79	1	// SPDX-License-Identifier: GPL-2.0
913965c4	2	#include <linux/cred.h>
fbb0de79	3	#include <linux/device.h>
fbb0de79 GH	4	#include <linux/dma-buf.h>
fbb0de79 GH	5	#include <linux/highmem.h>
913965c4 GH	6	#include <linux/init.h>
913965c4 GH	7	#include <linux/kernel.h>
fbb0de79	8	#include <linux/memfd.h>
913965c4 GH	9	#include <linux/miscdevice.h>
	10	#include <linux/module.h>
	11	#include <linux/shmem_fs.h>
	12	#include <linux/slab.h>
	13	#include <linux/udmabuf.h>
fbb0de79	14
dc4716d7 GH	15	static const u32 list_limit = 1024; /* udmabuf_create_list->count limit */
	16	static const size_t size_limit_mb = 64; /* total dmabuf size, in megabytes */
	17
fbb0de79	18	struct udmabuf {
b35f57c4	19	pgoff_t pagecount;
fbb0de79 GH	20	struct page **pages;
	21	};
	22
300133d3	23	static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf)
fbb0de79 GH	24	{
	25	struct vm_area_struct *vma = vmf->vma;
	26	struct udmabuf *ubuf = vma->vm_private_data;
	27
fbb0de79 GH	28	vmf->page = ubuf->pages[vmf->pgoff];
	29	get_page(vmf->page);
	30	return 0;
	31	}
	32
	33	static const struct vm_operations_struct udmabuf_vm_ops = {
	34	.fault = udmabuf_vm_fault,
	35	};
	36
	37	static int mmap_udmabuf(struct dma_buf buf, struct vm_area_struct vma)
	38	{
	39	struct udmabuf *ubuf = buf->priv;
	40
	41	if ((vma->vm_flags & (VM_SHARED \| VM_MAYSHARE)) == 0)
	42	return -EINVAL;
	43
	44	vma->vm_ops = &udmabuf_vm_ops;
	45	vma->vm_private_data = ubuf;
	46	return 0;
	47	}
	48
	49	static struct sg_table map_udmabuf(struct dma_buf_attachment at,
	50	enum dma_data_direction direction)
	51	{
	52	struct udmabuf *ubuf = at->dmabuf->priv;
	53	struct sg_table *sg;
a3e722da	54	int ret;
fbb0de79 GH	55
	56	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
	57	if (!sg)
a3e722da GH	58	return ERR_PTR(-ENOMEM);
	59	ret = sg_alloc_table_from_pages(sg, ubuf->pages, ubuf->pagecount,
	60	0, ubuf->pagecount << PAGE_SHIFT,
	61	GFP_KERNEL);
	62	if (ret < 0)
	63	goto err;
6f19eb21 DC	64	if (!dma_map_sg(at->dev, sg->sgl, sg->nents, direction)) {
6f19eb21 DC	65	ret = -EINVAL;
a3e722da	66	goto err;
6f19eb21	67	}
fbb0de79 GH	68	return sg;
fbb0de79 GH	69
a3e722da	70	err:
fbb0de79	71	sg_free_table(sg);
fbb0de79	72	kfree(sg);
a3e722da	73	return ERR_PTR(ret);
fbb0de79 GH	74	}
	75
	76	static void unmap_udmabuf(struct dma_buf_attachment *at,
	77	struct sg_table *sg,
	78	enum dma_data_direction direction)
	79	{
283f1e38	80	dma_unmap_sg(at->dev, sg->sgl, sg->nents, direction);
fbb0de79 GH	81	sg_free_table(sg);
	82	kfree(sg);
	83	}
	84
	85	static void release_udmabuf(struct dma_buf *buf)
	86	{
	87	struct udmabuf *ubuf = buf->priv;
	88	pgoff_t pg;
	89
	90	for (pg = 0; pg < ubuf->pagecount; pg++)
	91	put_page(ubuf->pages[pg]);
	92	kfree(ubuf->pages);
	93	kfree(ubuf);
	94	}
	95
	96	static void kmap_udmabuf(struct dma_buf buf, unsigned long page_num)
	97	{
	98	struct udmabuf *ubuf = buf->priv;
	99	struct page *page = ubuf->pages[page_num];
	100
	101	return kmap(page);
	102	}
	103
	104	static void kunmap_udmabuf(struct dma_buf *buf, unsigned long page_num,
	105	void *vaddr)
	106	{
	107	kunmap(vaddr);
	108	}
	109
a3485289	110	static const struct dma_buf_ops udmabuf_ops = {
fbb0de79 GH	111	.map_dma_buf = map_udmabuf,
	112	.unmap_dma_buf = unmap_udmabuf,
	113	.release = release_udmabuf,
	114	.map = kmap_udmabuf,
	115	.unmap = kunmap_udmabuf,
	116	.mmap = mmap_udmabuf,
	117	};
	118
	119	#define SEALS_WANTED (F_SEAL_SHRINK)
	120	#define SEALS_DENIED (F_SEAL_WRITE)
	121
dc254553 GH	122	static long udmabuf_create(const struct udmabuf_create_list *head,
dc254553 GH	123	const struct udmabuf_create_item *list)
fbb0de79 GH	124	{
	125	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
	126	struct file *memfd = NULL;
	127	struct udmabuf *ubuf;
	128	struct dma_buf *buf;
0d17455c	129	pgoff_t pgoff, pgcnt, pgidx, pgbuf = 0, pglimit;
fbb0de79 GH	130	struct page *page;
	131	int seals, ret = -EINVAL;
	132	u32 i, flags;
	133
33f35429	134	ubuf = kzalloc(sizeof(*ubuf), GFP_KERNEL);
fbb0de79 GH	135	if (!ubuf)
	136	return -ENOMEM;
	137
dc4716d7	138	pglimit = (size_limit_mb * 1024 * 1024) >> PAGE_SHIFT;
fbb0de79 GH	139	for (i = 0; i < head->count; i++) {
fbb0de79 GH	140	if (!IS_ALIGNED(list[i].offset, PAGE_SIZE))
0d17455c	141	goto err;
fbb0de79	142	if (!IS_ALIGNED(list[i].size, PAGE_SIZE))
0d17455c	143	goto err;
fbb0de79	144	ubuf->pagecount += list[i].size >> PAGE_SHIFT;
dc4716d7	145	if (ubuf->pagecount > pglimit)
0d17455c	146	goto err;
fbb0de79	147	}
33f35429	148	ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(*ubuf->pages),
fbb0de79 GH	149	GFP_KERNEL);
	150	if (!ubuf->pages) {
	151	ret = -ENOMEM;
0d17455c	152	goto err;
fbb0de79 GH	153	}
	154
	155	pgbuf = 0;
	156	for (i = 0; i < head->count; i++) {
7a1c67d7	157	ret = -EBADFD;
fbb0de79 GH	158	memfd = fget(list[i].memfd);
fbb0de79 GH	159	if (!memfd)
0d17455c	160	goto err;
fbb0de79	161	if (!shmem_mapping(file_inode(memfd)->i_mapping))
0d17455c	162	goto err;
fbb0de79	163	seals = memfd_fcntl(memfd, F_GET_SEALS, 0);
7a1c67d7 GH	164	if (seals == -EINVAL)
	165	goto err;
	166	ret = -EINVAL;
	167	if ((seals & SEALS_WANTED) != SEALS_WANTED \|\|
fbb0de79	168	(seals & SEALS_DENIED) != 0)
0d17455c	169	goto err;
fbb0de79 GH	170	pgoff = list[i].offset >> PAGE_SHIFT;
	171	pgcnt = list[i].size >> PAGE_SHIFT;
	172	for (pgidx = 0; pgidx < pgcnt; pgidx++) {
	173	page = shmem_read_mapping_page(
	174	file_inode(memfd)->i_mapping, pgoff + pgidx);
	175	if (IS_ERR(page)) {
	176	ret = PTR_ERR(page);
0d17455c	177	goto err;
fbb0de79 GH	178	}
	179	ubuf->pages[pgbuf++] = page;
	180	}
	181	fput(memfd);
0d17455c	182	memfd = NULL;
fbb0de79	183	}
fbb0de79 GH	184
	185	exp_info.ops = &udmabuf_ops;
	186	exp_info.size = ubuf->pagecount << PAGE_SHIFT;
	187	exp_info.priv = ubuf;
5c074eea	188	exp_info.flags = O_RDWR;
fbb0de79 GH	189
	190	buf = dma_buf_export(&exp_info);
	191	if (IS_ERR(buf)) {
	192	ret = PTR_ERR(buf);
0d17455c	193	goto err;
fbb0de79 GH	194	}
	195
	196	flags = 0;
	197	if (head->flags & UDMABUF_FLAGS_CLOEXEC)
	198	flags \|= O_CLOEXEC;
	199	return dma_buf_fd(buf, flags);
	200
0d17455c	201	err:
fbb0de79 GH	202	while (pgbuf > 0)
fbb0de79 GH	203	put_page(ubuf->pages[--pgbuf]);
683a0e63 GS	204	if (memfd)
683a0e63 GS	205	fput(memfd);
fbb0de79 GH	206	kfree(ubuf->pages);
	207	kfree(ubuf);
	208	return ret;
	209	}
	210
	211	static long udmabuf_ioctl_create(struct file *filp, unsigned long arg)
	212	{
	213	struct udmabuf_create create;
	214	struct udmabuf_create_list head;
	215	struct udmabuf_create_item list;
	216
	217	if (copy_from_user(&create, (void __user *)arg,
33f35429	218	sizeof(create)))
fbb0de79 GH	219	return -EFAULT;
	220
	221	head.flags = create.flags;
	222	head.count = 1;
	223	list.memfd = create.memfd;
	224	list.offset = create.offset;
	225	list.size = create.size;
	226
	227	return udmabuf_create(&head, &list);
	228	}
	229
	230	static long udmabuf_ioctl_create_list(struct file *filp, unsigned long arg)
	231	{
	232	struct udmabuf_create_list head;
	233	struct udmabuf_create_item *list;
	234	int ret = -EINVAL;
	235	u32 lsize;
	236
	237	if (copy_from_user(&head, (void __user *)arg, sizeof(head)))
	238	return -EFAULT;
dc4716d7	239	if (head.count > list_limit)
fbb0de79 GH	240	return -EINVAL;
	241	lsize = sizeof(struct udmabuf_create_item) * head.count;
	242	list = memdup_user((void __user *)(arg + sizeof(head)), lsize);
	243	if (IS_ERR(list))
	244	return PTR_ERR(list);
	245
	246	ret = udmabuf_create(&head, list);
	247	kfree(list);
	248	return ret;
	249	}
	250
	251	static long udmabuf_ioctl(struct file *filp, unsigned int ioctl,
	252	unsigned long arg)
	253	{
	254	long ret;
	255
	256	switch (ioctl) {
	257	case UDMABUF_CREATE:
	258	ret = udmabuf_ioctl_create(filp, arg);
	259	break;
	260	case UDMABUF_CREATE_LIST:
	261	ret = udmabuf_ioctl_create_list(filp, arg);
	262	break;
	263	default:
52499d9c	264	ret = -ENOTTY;
fbb0de79 GH	265	break;
	266	}
	267	return ret;
	268	}
	269
	270	static const struct file_operations udmabuf_fops = {
	271	.owner = THIS_MODULE,
	272	.unlocked_ioctl = udmabuf_ioctl,
	273	};
	274
	275	static struct miscdevice udmabuf_misc = {
	276	.minor = MISC_DYNAMIC_MINOR,
	277	.name = "udmabuf",
	278	.fops = &udmabuf_fops,
	279	};
	280
	281	static int __init udmabuf_dev_init(void)
	282	{
	283	return misc_register(&udmabuf_misc);
	284	}
	285
	286	static void __exit udmabuf_dev_exit(void)
	287	{
	288	misc_deregister(&udmabuf_misc);
	289	}
	290
	291	module_init(udmabuf_dev_init)
	292	module_exit(udmabuf_dev_exit)
	293
	294	MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");
	295	MODULE_LICENSE("GPL v2");