kvm: switch get_user_page_nowait() to get_user_pages_unlocked()

... and fold into the sole caller, unifying async and non-async cases

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f169ecc4f2e87f44ece32540b8428529aa01ae84..ae4985bc8a8aec1f8b5ac850fda5b36c5cc55a2a 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1314,17 +1314,6 @@ unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *w
        return gfn_to_hva_memslot_prot(slot, gfn, writable);
 }
 
-static int get_user_page_nowait(unsigned long start, int write,
-               struct page **page)
-{
-       int flags = FOLL_NOWAIT | FOLL_HWPOISON;
-
-       if (write)
-               flags |= FOLL_WRITE;
-
-       return get_user_pages(start, 1, flags, page, NULL);
-}
-
 static inline int check_user_page_hwpoison(unsigned long addr)
 {
        int rc, flags = FOLL_HWPOISON | FOLL_WRITE;
@@ -1373,7 +1362,8 @@ static bool hva_to_pfn_fast(unsigned long addr, bool atomic, bool *async,
 static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
                           bool *writable, kvm_pfn_t *pfn)
 {
-       struct page *page[1];
+       unsigned int flags = FOLL_HWPOISON;
+       struct page *page;
        int npages = 0;
 
        might_sleep();
@@ -1381,35 +1371,26 @@ static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
        if (writable)
                *writable = write_fault;
 
-       if (async) {
-               down_read(&current->mm->mmap_sem);
-               npages = get_user_page_nowait(addr, write_fault, page);
-               up_read(&current->mm->mmap_sem);
-       } else {
-               unsigned int flags = FOLL_HWPOISON;
-
-               if (write_fault)
-                       flags |= FOLL_WRITE;
+       if (write_fault)
+               flags |= FOLL_WRITE;
+       if (async)
+               flags |= FOLL_NOWAIT;
 
-               npages = get_user_pages_unlocked(addr, 1, page, flags);
-       }
+       npages = get_user_pages_unlocked(addr, 1, &page, flags);
        if (npages != 1)
                return npages;
 
        /* map read fault as writable if possible */
        if (unlikely(!write_fault) && writable) {
-               struct page *wpage[1];
+               struct page *wpage;
 
-               npages = __get_user_pages_fast(addr, 1, 1, wpage);
-               if (npages == 1) {
+               if (__get_user_pages_fast(addr, 1, 1, &wpage) == 1) {
                        *writable = true;
-                       put_page(page[0]);
-                       page[0] = wpage[0];
+                       put_page(page);
+                       page = wpage;
                }
-
-               npages = 1;
        }
-       *pfn = page_to_pfn(page[0]);
+       *pfn = page_to_pfn(page);
        return npages;
 }