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>

1 files changed, 12 insertions, 31 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f169ecc4f2e8..ae4985bc8a8a 100644
--- 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;
 }