vmw_vmci: Convert driver to use get_user_pages_fast()

Convert vmci_host_setup_notify() and qp_host_get_user_memory() to use
get_user_pages_fast() instead of get_user_pages(). Note that
qp_host_get_user_memory() was using mmap_sem for writing without an
apparent reason.

CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 7 insertions, 20 deletions

diff --git a/drivers/misc/vmw_vmci/vmci_host.c b/drivers/misc/vmw_vmci/vmci_host.c
index d4722b3dc8ec..1723a6e4f2e8 100644
--- a/drivers/misc/vmw_vmci/vmci_host.c
+++ b/drivers/misc/vmw_vmci/vmci_host.c
@@ -243,11 +243,7 @@ static int vmci_host_setup_notify(struct vmci_ctx *context,
         /*
          * Lock physical page backing a given user VA.
          */
-        down_read(&current->mm->mmap_sem);
-        retval = get_user_pages(current, current->mm,
-                                PAGE_ALIGN(uva),
-                                1, 1, 0, &page, NULL);
-        up_read(&current->mm->mmap_sem);
+        retval = get_user_pages_fast(PAGE_ALIGN(uva), 1, 1, &page);
         if (retval != 1)
                 return VMCI_ERROR_GENERIC;
 
diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
index a0515a6d6ebd..1b7b303085d2 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
@@ -732,13 +732,9 @@ static int qp_host_get_user_memory(u64 produce_uva,
         int retval;
         int err = VMCI_SUCCESS;
 
-        down_write(&current->mm->mmap_sem);
-        retval = get_user_pages(current,
-                                current->mm,
-                                (uintptr_t) produce_uva,
-                                produce_q->kernel_if->num_pages,
-                                1, 0,
-                                produce_q->kernel_if->u.h.header_page, NULL);
+        retval = get_user_pages_fast((uintptr_t) produce_uva,
+                                     produce_q->kernel_if->num_pages, 1,
+                                     produce_q->kernel_if->u.h.header_page);
         if (retval < produce_q->kernel_if->num_pages) {
                 pr_warn("get_user_pages(produce) failed (retval=%d)", retval);
                 qp_release_pages(produce_q->kernel_if->u.h.header_page,
@@ -747,12 +743,9 @@ static int qp_host_get_user_memory(u64 produce_uva,
                 goto out;
         }
 
-        retval = get_user_pages(current,
-                                current->mm,
-                                (uintptr_t) consume_uva,
-                                consume_q->kernel_if->num_pages,
-                                1, 0,
-                                consume_q->kernel_if->u.h.header_page, NULL);
+        retval = get_user_pages_fast((uintptr_t) consume_uva,
+                                     consume_q->kernel_if->num_pages, 1,
+                                     consume_q->kernel_if->u.h.header_page);
         if (retval < consume_q->kernel_if->num_pages) {
                 pr_warn("get_user_pages(consume) failed (retval=%d)", retval);
                 qp_release_pages(consume_q->kernel_if->u.h.header_page,
@@ -763,8 +756,6 @@ static int qp_host_get_user_memory(u64 produce_uva,
         }
 
  out:
-        up_write(&current->mm->mmap_sem);
-
         return err;
 }