Commit 5e72b2b4 authored by Vivek Kasireddy's avatar Vivek Kasireddy Committed by Andrew Morton
Browse files

udmabuf: convert udmabuf driver to use folios 

This is mainly a preparatory patch to use memfd_pin_folios() API for
pinning folios.  Using folios instead of pages makes sense as the udmabuf
driver needs to handle both shmem and hugetlb cases.  And, using the
memfd_pin_folios() API makes this easier as we no longer need to
separately handle shmem vs hugetlb cases in the udmabuf driver.

Note that, the function vmap_udmabuf() still needs a list of pages; so, we
collect all the head pages into a local array in this case.

Other changes in this patch include the addition of helpers for checking
the memfd seals and exporting dmabuf.  Moving code from udmabuf_create()
into these helpers improves readability given that udmabuf_create() is a
bit long.

Link: https://lkml.kernel.org/r/20240624063952.1572359-8-vivek.kasireddy@intel.com


Signed-off-by: default avatarVivek Kasireddy <vivek.kasireddy@intel.com>
Acked-by: default avatarDave Airlie <airlied@redhat.com>
Acked-by: default avatarGerd Hoffmann <kraxel@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: Junxiao Chang <junxiao.chang@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 0c8b91ef

drivers/dma-buf/udmabuf.c

+83 −56
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ MODULE_PARM_DESC(size_limit_mb, "Max size of a dmabuf, in megabytes. Default is 


struct udmabuf {

	pgoff_t pagecount;

	struct page **pages;

	struct folio **folios;

	struct sg_table *sg;

	struct miscdevice *device;

	pgoff_t *offsets;
@@ -42,7 +42,7 @@ static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) 
	if (pgoff >= ubuf->pagecount)

		return VM_FAULT_SIGBUS;



	pfn = page_to_pfn(ubuf->pages[pgoff]);

	pfn = folio_pfn(ubuf->folios[pgoff]);

	pfn += ubuf->offsets[pgoff] >> PAGE_SHIFT;



	return vmf_insert_pfn(vma, vmf->address, pfn);
@@ -68,11 +68,21 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma) 
static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map)

{

	struct udmabuf *ubuf = buf->priv;

	struct page **pages;

	void *vaddr;

	pgoff_t pg;



	dma_resv_assert_held(buf->resv);



	vaddr = vm_map_ram(ubuf->pages, ubuf->pagecount, -1);

	pages = kmalloc_array(ubuf->pagecount, sizeof(*pages), GFP_KERNEL);

	if (!pages)

		return -ENOMEM;



	for (pg = 0; pg < ubuf->pagecount; pg++)

		pages[pg] = &ubuf->folios[pg]->page;



	vaddr = vm_map_ram(pages, ubuf->pagecount, -1);

	kfree(pages);

	if (!vaddr)

		return -EINVAL;
@@ -107,7 +117,8 @@ static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, 
		goto err_alloc;



	for_each_sg(sg->sgl, sgl, ubuf->pagecount, i)

		sg_set_page(sgl, ubuf->pages[i], PAGE_SIZE, ubuf->offsets[i]);

		sg_set_folio(sgl, ubuf->folios[i], PAGE_SIZE,

			     ubuf->offsets[i]);



	ret = dma_map_sgtable(dev, sg, direction, 0);

	if (ret < 0)
@@ -152,9 +163,9 @@ static void release_udmabuf(struct dma_buf *buf) 
		put_sg_table(dev, ubuf->sg, DMA_BIDIRECTIONAL);



	for (pg = 0; pg < ubuf->pagecount; pg++)

		put_page(ubuf->pages[pg]);

		folio_put(ubuf->folios[pg]);

	kfree(ubuf->offsets);

	kfree(ubuf->pages);

	kfree(ubuf->folios);

	kfree(ubuf);

}
@@ -215,36 +226,33 @@ static int handle_hugetlb_pages(struct udmabuf *ubuf, struct file *memfd, 
	pgoff_t mapidx = offset >> huge_page_shift(hpstate);

	pgoff_t subpgoff = (offset & ~huge_page_mask(hpstate)) >> PAGE_SHIFT;

	pgoff_t maxsubpgs = huge_page_size(hpstate) >> PAGE_SHIFT;

	struct page *hpage = NULL;

	struct folio *folio;

	struct folio *folio = NULL;

	pgoff_t pgidx;



	mapidx <<= huge_page_order(hpstate);

	for (pgidx = 0; pgidx < pgcnt; pgidx++) {

		if (!hpage) {

		if (!folio) {

			folio = __filemap_get_folio(memfd->f_mapping,

						    mapidx,

						    FGP_ACCESSED, 0);

			if (IS_ERR(folio))

				return PTR_ERR(folio);



			hpage = &folio->page;

		}



		get_page(hpage);

		ubuf->pages[*pgbuf] = hpage;

		folio_get(folio);

		ubuf->folios[*pgbuf] = folio;

		ubuf->offsets[*pgbuf] = subpgoff << PAGE_SHIFT;

		(*pgbuf)++;

		if (++subpgoff == maxsubpgs) {

			put_page(hpage);

			hpage = NULL;

			folio_put(folio);

			folio = NULL;

			subpgoff = 0;

			mapidx += pages_per_huge_page(hpstate);

		}

	}



	if (hpage)

		put_page(hpage);

	if (folio)

		folio_put(folio);



	return 0;

}
@@ -254,31 +262,69 @@ static int handle_shmem_pages(struct udmabuf *ubuf, struct file *memfd, 
			      pgoff_t *pgbuf)

{

	pgoff_t pgidx, pgoff = offset >> PAGE_SHIFT;

	struct page *page;

	struct folio *folio = NULL;



	for (pgidx = 0; pgidx < pgcnt; pgidx++) {

		page = shmem_read_mapping_page(memfd->f_mapping,

					       pgoff + pgidx);

		if (IS_ERR(page))

			return PTR_ERR(page);

		folio = shmem_read_folio(memfd->f_mapping, pgoff + pgidx);

		if (IS_ERR(folio))

			return PTR_ERR(folio);



		ubuf->pages[*pgbuf] = page;

		ubuf->folios[*pgbuf] = folio;

		(*pgbuf)++;

	}



	return 0;

}



static int check_memfd_seals(struct file *memfd)

{

	int seals;



	if (!memfd)

		return -EBADFD;



	if (!shmem_file(memfd) && !is_file_hugepages(memfd))

		return -EBADFD;



	seals = memfd_fcntl(memfd, F_GET_SEALS, 0);

	if (seals == -EINVAL)

		return -EBADFD;



	if ((seals & SEALS_WANTED) != SEALS_WANTED ||

	    (seals & SEALS_DENIED) != 0)

		return -EINVAL;



	return 0;

}



static int export_udmabuf(struct udmabuf *ubuf,

			  struct miscdevice *device,

			  u32 flags)

{

	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);

	struct dma_buf *buf;



	ubuf->device = device;

	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))

		return PTR_ERR(buf);



	return dma_buf_fd(buf, flags);

}



static long udmabuf_create(struct miscdevice *device,

			   struct udmabuf_create_list *head,

			   struct udmabuf_create_item *list)

{

	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);

	pgoff_t pgcnt, pgbuf = 0, pglimit;

	struct file *memfd = NULL;

	struct udmabuf *ubuf;

	struct dma_buf *buf;

	pgoff_t pgcnt, pgbuf = 0, pglimit;

	int seals, ret = -EINVAL;

	int ret = -EINVAL;

	u32 i, flags;



	ubuf = kzalloc(sizeof(*ubuf), GFP_KERNEL);
@@ -299,9 +345,9 @@ static long udmabuf_create(struct miscdevice *device, 
	if (!ubuf->pagecount)

		goto err;



	ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(*ubuf->pages),

	ubuf->folios = kmalloc_array(ubuf->pagecount, sizeof(*ubuf->folios),

				    GFP_KERNEL);

	if (!ubuf->pages) {

	if (!ubuf->folios) {

		ret = -ENOMEM;

		goto err;

	}
@@ -314,18 +360,9 @@ static long udmabuf_create(struct miscdevice *device, 


	pgbuf = 0;

	for (i = 0; i < head->count; i++) {

		ret = -EBADFD;

		memfd = fget(list[i].memfd);

		if (!memfd)

			goto err;

		if (!shmem_file(memfd) && !is_file_hugepages(memfd))

			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)

		ret = check_memfd_seals(memfd);

		if (ret < 0)

			goto err;



		pgcnt = list[i].size >> PAGE_SHIFT;
@@ -344,30 +381,20 @@ static long udmabuf_create(struct miscdevice *device, 
		memfd = NULL;

	}



	exp_info.ops  = &udmabuf_ops;

	exp_info.size = ubuf->pagecount << PAGE_SHIFT;

	exp_info.priv = ubuf;

	exp_info.flags = O_RDWR;



	ubuf->device = device;

	buf = dma_buf_export(&exp_info);

	if (IS_ERR(buf)) {

		ret = PTR_ERR(buf);

	flags = head->flags & UDMABUF_FLAGS_CLOEXEC ? O_CLOEXEC : 0;

	ret = export_udmabuf(ubuf, device, flags);

	if (ret < 0)

		goto err;

	}



	flags = 0;

	if (head->flags & UDMABUF_FLAGS_CLOEXEC)

		flags |= O_CLOEXEC;

	return dma_buf_fd(buf, flags);

	return ret;



err:

	while (pgbuf > 0)

		put_page(ubuf->pages[--pgbuf]);

		folio_put(ubuf->folios[--pgbuf]);

	if (memfd)

		fput(memfd);

	kfree(ubuf->offsets);

	kfree(ubuf->pages);

	kfree(ubuf->folios);

	kfree(ubuf);

	return ret;

}