rapidio: use get_user_pages_unlocked()

Moving from get_user_pages() to get_user_pages_unlocked() simplifies the
code and takes advantage of VM_FAULT_RETRY functionality when faulting
in pages.

Link: http://lkml.kernel.org/r/20170103205024.6704-1-lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c
index 9013a585507e8a80b4580c084445ec7bbde6e04c..50b617af81bd5a2d034798bfa27f2cfa8da97bde 100644 (file)
--- a/drivers/rapidio/devices/rio_mport_cdev.c
+++ b/drivers/rapidio/devices/rio_mport_cdev.c
@@ -889,17 +889,16 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode,
                        goto err_req;
                }
 
-               down_read(&current->mm->mmap_sem);
-               pinned = get_user_pages(
+               pinned = get_user_pages_unlocked(
                                (unsigned long)xfer->loc_addr & PAGE_MASK,
                                nr_pages,
-                               dir == DMA_FROM_DEVICE ? FOLL_WRITE : 0,
-                               page_list, NULL);
-               up_read(&current->mm->mmap_sem);
+                               page_list,
+                               dir == DMA_FROM_DEVICE ? FOLL_WRITE : 0);
 
                if (pinned != nr_pages) {
                        if (pinned < 0) {
-                               rmcd_error("get_user_pages err=%ld", pinned);
+                               rmcd_error("get_user_pages_unlocked err=%ld",
+                                          pinned);
                                nr_pages = 0;
                        } else
                                rmcd_error("pinned %ld out of %ld pages",