1 files changed, 76 insertions, 61 deletions

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index aa182a9dcdfa..9d58c045b8eb 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -291,9 +291,6 @@ static int check_memfd_seals(struct file *memfd)
 {
 	int seals;
 
-	if (!memfd)
-		return -EBADFD;
-
 	if (!shmem_file(memfd) && !is_file_hugepages(memfd))
 		return -EBADFD;
 
@@ -328,17 +325,68 @@ static int export_udmabuf(struct udmabuf *ubuf,
 	return dma_buf_fd(buf, flags);
 }
 
+static long udmabuf_pin_folios(struct udmabuf *ubuf, struct file *memfd,
+			       loff_t start, loff_t size)
+{
+	pgoff_t pgoff, pgcnt, upgcnt = ubuf->pagecount;
+	struct folio **folios = NULL;
+	u32 cur_folio, cur_pgcnt;
+	long nr_folios;
+	long ret = 0;
+	loff_t end;
+
+	pgcnt = size >> PAGE_SHIFT;
+	folios = kvmalloc_array(pgcnt, sizeof(*folios), GFP_KERNEL);
+	if (!folios)
+		return -ENOMEM;
+
+	end = start + (pgcnt << PAGE_SHIFT) - 1;
+	nr_folios = memfd_pin_folios(memfd, start, end, folios, pgcnt, &pgoff);
+	if (nr_folios <= 0) {
+		ret = nr_folios ? nr_folios : -EINVAL;
+		goto end;
+	}
+
+	cur_pgcnt = 0;
+	for (cur_folio = 0; cur_folio < nr_folios; ++cur_folio) {
+		pgoff_t subpgoff = pgoff;
+		size_t fsize = folio_size(folios[cur_folio]);
+
+		ret = add_to_unpin_list(&ubuf->unpin_list, folios[cur_folio]);
+		if (ret < 0)
+			goto end;
+
+		for (; subpgoff < fsize; subpgoff += PAGE_SIZE) {
+			ubuf->folios[upgcnt] = folios[cur_folio];
+			ubuf->offsets[upgcnt] = subpgoff;
+			++upgcnt;
+
+			if (++cur_pgcnt >= pgcnt)
+				goto end;
+		}
+
+		/**
+		 * In a given range, only the first subpage of the first folio
+		 * has an offset, that is returned by memfd_pin_folios().
+		 * The first subpages of other folios (in the range) have an
+		 * offset of 0.
+		 */
+		pgoff = 0;
+	}
+end:
+	ubuf->pagecount = upgcnt;
+	kvfree(folios);
+	return ret;
+}
+
 static long udmabuf_create(struct miscdevice *device,
 			   struct udmabuf_create_list *head,
 			   struct udmabuf_create_item *list)
 {
-	pgoff_t pgoff, pgcnt, pglimit, pgbuf = 0;
-	long nr_folios, ret = -EINVAL;
-	struct file *memfd = NULL;
-	struct folio **folios;
+	pgoff_t pgcnt = 0, pglimit;
 	struct udmabuf *ubuf;
-	u32 i, j, k, flags;
-	loff_t end;
+	long ret = -EINVAL;
+	u32 i, flags;
 
 	ubuf = kzalloc(sizeof(*ubuf), GFP_KERNEL);
 	if (!ubuf)
@@ -347,81 +395,50 @@ static long udmabuf_create(struct miscdevice *device,
 	INIT_LIST_HEAD(&ubuf->unpin_list);
 	pglimit = (size_limit_mb * 1024 * 1024) >> PAGE_SHIFT;
 	for (i = 0; i < head->count; i++) {
-		if (!IS_ALIGNED(list[i].offset, PAGE_SIZE))
+		if (!PAGE_ALIGNED(list[i].offset))
 			goto err;
-		if (!IS_ALIGNED(list[i].size, PAGE_SIZE))
+		if (!PAGE_ALIGNED(list[i].size))
 			goto err;
-		ubuf->pagecount += list[i].size >> PAGE_SHIFT;
-		if (ubuf->pagecount > pglimit)
+
+		pgcnt += list[i].size >> PAGE_SHIFT;
+		if (pgcnt > pglimit)
 			goto err;
 	}
 
-	if (!ubuf->pagecount)
+	if (!pgcnt)
 		goto err;
 
-	ubuf->folios = kvmalloc_array(ubuf->pagecount, sizeof(*ubuf->folios),
-				      GFP_KERNEL);
+	ubuf->folios = kvmalloc_array(pgcnt, sizeof(*ubuf->folios), GFP_KERNEL);
 	if (!ubuf->folios) {
 		ret = -ENOMEM;
 		goto err;
 	}
-	ubuf->offsets = kvcalloc(ubuf->pagecount, sizeof(*ubuf->offsets),
-				 GFP_KERNEL);
+
+	ubuf->offsets = kvcalloc(pgcnt, sizeof(*ubuf->offsets), GFP_KERNEL);
 	if (!ubuf->offsets) {
 		ret = -ENOMEM;
 		goto err;
 	}
 
-	pgbuf = 0;
 	for (i = 0; i < head->count; i++) {
-		memfd = fget(list[i].memfd);
-		ret = check_memfd_seals(memfd);
-		if (ret < 0)
-			goto err;
+		struct file *memfd = fget(list[i].memfd);
 
-		pgcnt = list[i].size >> PAGE_SHIFT;
-		folios = kvmalloc_array(pgcnt, sizeof(*folios), GFP_KERNEL);
-		if (!folios) {
-			ret = -ENOMEM;
+		if (!memfd) {
+			ret = -EBADFD;
 			goto err;
 		}
 
-		end = list[i].offset + (pgcnt << PAGE_SHIFT) - 1;
-		ret = memfd_pin_folios(memfd, list[i].offset, end,
-				       folios, pgcnt, &pgoff);
-		if (ret <= 0) {
-			kvfree(folios);
-			if (!ret)
-				ret = -EINVAL;
+		ret = check_memfd_seals(memfd);
+		if (ret < 0) {
+			fput(memfd);
 			goto err;
 		}
 
-		nr_folios = ret;
-		pgoff >>= PAGE_SHIFT;
-		for (j = 0, k = 0; j < pgcnt; j++) {
-			ubuf->folios[pgbuf] = folios[k];
-			ubuf->offsets[pgbuf] = pgoff << PAGE_SHIFT;
-
-			if (j == 0 || ubuf->folios[pgbuf-1] != folios[k]) {
-				ret = add_to_unpin_list(&ubuf->unpin_list,
-							folios[k]);
-				if (ret < 0) {
-					kfree(folios);
-					goto err;
-				}
-			}
-
-			pgbuf++;
-			if (++pgoff == folio_nr_pages(folios[k])) {
-				pgoff = 0;
-				if (++k == nr_folios)
-					break;
-			}
-		}
-
-		kvfree(folios);
+		ret = udmabuf_pin_folios(ubuf, memfd, list[i].offset,
+					 list[i].size);
 		fput(memfd);
-		memfd = NULL;
+		if (ret)
+			goto err;
 	}
 
 	flags = head->flags & UDMABUF_FLAGS_CLOEXEC ? O_CLOEXEC : 0;
@@ -432,8 +449,6 @@ static long udmabuf_create(struct miscdevice *device,
 	return ret;
 
 err:
-	if (memfd)
-		fput(memfd);
 	unpin_all_folios(&ubuf->unpin_list);
 	kvfree(ubuf->offsets);
 	kvfree(ubuf->folios);