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Commit dc4716d7 authored by Gerd Hoffmann's avatar Gerd Hoffmann
Browse files

udmabuf: rework limits 



Create variable for the list length limit.  Serves as documentation,
also allows to make it a module parameter if needed.

Also add a total size limit.

Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
Acked-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20180911134216.9760-8-kraxel@redhat.com
parent 68d2f70e

drivers/dma-buf/udmabuf.c

+8 −2
Original line number Diff line number Diff line
@@ -12,6 +12,9 @@ 
#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;
@@ -123,7 +126,7 @@ static long udmabuf_create(const struct udmabuf_create_list *head, 
	struct file *memfd = NULL;

	struct udmabuf *ubuf;

	struct dma_buf *buf;

	pgoff_t pgoff, pgcnt, pgidx, pgbuf;

	pgoff_t pgoff, pgcnt, pgidx, pgbuf, pglimit;

	struct page *page;

	int seals, ret = -EINVAL;

	u32 i, flags;
@@ -132,12 +135,15 @@ static long udmabuf_create(const struct udmabuf_create_list *head, 
	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_free_ubuf;

		if (!IS_ALIGNED(list[i].size, PAGE_SIZE))

			goto err_free_ubuf;

		ubuf->pagecount += list[i].size >> PAGE_SHIFT;

		if (ubuf->pagecount > pglimit)

			goto err_free_ubuf;

	}

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

				    GFP_KERNEL);
@@ -227,7 +233,7 @@ static long udmabuf_ioctl_create_list(struct file *filp, unsigned long arg) 


	if (copy_from_user(&head, (void __user *)arg, sizeof(head)))

		return -EFAULT;

	if (head.count > 1024)

	if (head.count > list_limit)

		return -EINVAL;

	lsize = sizeof(struct udmabuf_create_item) * head.count;

	list = memdup_user((void __user *)(arg + sizeof(head)), lsize);