staging: kpc2000: kpc_dma: Convert get_user_pages() --> pin_user_pages()

In 2019, we introduced pin_user_pages*() and now we are converting
get_user_pages*() to the new API as appropriate. [1] & [2] could
be referred for more information. This is case 2 as per document [1].

[1] Documentation/core-api/pin_user_pages.rst

[2] "Explicit pinning of user-space pages":
        https://lwn.net/Articles/807108/

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Bharath Vedartham <linux.bhar@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/1593584264-16982-4-git-send-email-jrdr.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c
index 08d90a6..8cd20ad 100644 (file)
--- a/drivers/staging/kpc2000/kpc_dma/fileops.c
+++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
@@ -76,10 +76,10 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
 
        // Lock the user buffer pages in memory, and hold on to the page pointers (for the sglist)
        mmap_read_lock(current->mm);      /*  get memory map semaphore */
-       rv = get_user_pages(iov_base, acd->page_count, FOLL_TOUCH | FOLL_WRITE | FOLL_GET, acd->user_pages, NULL);
+       rv = pin_user_pages(iov_base, acd->page_count, FOLL_TOUCH | FOLL_WRITE, acd->user_pages, NULL);
        mmap_read_unlock(current->mm);        /*  release the semaphore */
        if (rv != acd->page_count) {
-               dev_err(&priv->ldev->pldev->dev, "Couldn't get_user_pages (%d)\n", rv);
+               dev_err(&priv->ldev->pldev->dev, "Couldn't pin_user_pages (%d)\n", rv);
                goto err_get_user_pages;
        }
 
@@ -189,13 +189,11 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
        sg_free_table(&acd->sgt);
  err_dma_map_sg:
  err_alloc_sg_table:
-       for (i = 0 ; i < acd->page_count ; i++)
-               put_page(acd->user_pages[i]);
+       unpin_user_pages(acd->user_pages, acd->page_count);
 
  err_get_user_pages:
        if (rv > 0) {
-               for (i = 0; i < rv; i++)
-                       put_pages(acd->user_pages[i]);
+               unpin_user_pages(acd->user_pages, rv);
                rv = -EFAULT;
        }
        kfree(acd->user_pages);
@@ -222,8 +220,7 @@ void  transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
                        set_page_dirty_lock(acd->user_pages[i]);
        }
 
-       for (i = 0 ; i < acd->page_count ; i++)
-               put_page(acd->user_pages[i]);
+       unpin_user_pages(acd->user_pages, acd->page_count);
 
        sg_free_table(&acd->sgt);