misc: genwqe: should return proper error value.

The function should return -EFAULT when copy_from_user fails. Even
though the caller does not distinguish them. but we should keep backward
compatibility.
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/genwqe/card_utils.c

@@ -298,7 +298,7 @@ static int genwqe_sgl_size(int num_pages)
 int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,
 			  void __user *user_addr, size_t user_size, int write)
 {
-	int rc;
+	int ret = -ENOMEM;
 	struct pci_dev *pci_dev = cd->pci_dev;
 
 	sgl->fpage_offs = offset_in_page((unsigned long)user_addr);
@@ -318,7 +318,7 @@ int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,
 	if (get_order(sgl->sgl_size) > MAX_ORDER) {
 		dev_err(&pci_dev->dev,
 			"[%s] err: too much memory requested!\n", __func__);
-		return -ENOMEM;
+		return ret;
 	}
 
 	sgl->sgl = __genwqe_alloc_consistent(cd, sgl->sgl_size,
@@ -326,7 +326,7 @@ int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,
 	if (sgl->sgl == NULL) {
 		dev_err(&pci_dev->dev,
 			"[%s] err: no memory available!\n", __func__);
-		return -ENOMEM;
+		return ret;
 	}
 
 	/* Only use buffering on incomplete pages */
@@ -339,7 +339,7 @@ int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,
 		/* Sync with user memory */
 		if (copy_from_user(sgl->fpage + sgl->fpage_offs,
 				   user_addr, sgl->fpage_size)) {
-			rc = -EFAULT;
+			ret = -EFAULT;
 			goto err_out;
 		}
 	}
@@ -352,7 +352,7 @@ int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,
 		/* Sync with user memory */
 		if (copy_from_user(sgl->lpage, user_addr + user_size -
 				   sgl->lpage_size, sgl->lpage_size)) {
-			rc = -EFAULT;
+			ret = -EFAULT;
 			goto err_out2;
 		}
 	}
@@ -374,7 +374,8 @@ int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,
 	sgl->sgl = NULL;
 	sgl->sgl_dma_addr = 0;
 	sgl->sgl_size = 0;
-	return -ENOMEM;
+
+	return ret;
 }
 
 int genwqe_setup_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,