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authorAndrea Arcangeli <aarcange@redhat.com>2015-02-11 15:27:28 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-11 17:06:05 -0800
commit0664e57ff0c68cbca012a45a38288fa277eb6795 (patch)
tree6f660902ba6ae3c834182e15165143b9a57b2477 /virt
parent7e339128496284cc21977fba5416166ee81f5172 (diff)
downloadkernel-0664e57ff0c68cbca012a45a38288fa277eb6795.tar.gz
mm: gup: kvm use get_user_pages_unlocked
Use the more generic get_user_pages_unlocked which has the additional benefit of passing FAULT_FLAG_ALLOW_RETRY at the very first page fault (which allows the first page fault in an unmapped area to be always able to block indefinitely by being allowed to release the mmap_sem). Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Peter Feiner <pfeiner@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/async_pf.c2
-rw-r--r--virt/kvm/kvm_main.c50
2 files changed, 5 insertions, 47 deletions
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 5ff7f7f2689a..44660aee335f 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -80,7 +80,7 @@ static void async_pf_execute(struct work_struct *work)
might_sleep();
- kvm_get_user_page_io(NULL, mm, addr, 1, NULL);
+ get_user_pages_unlocked(NULL, mm, addr, 1, 1, 0, NULL);
kvm_async_page_present_sync(vcpu, apf);
spin_lock(&vcpu->async_pf.lock);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1cc6e2e19982..458b9b14b15c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1128,43 +1128,6 @@ static int get_user_page_nowait(struct task_struct *tsk, struct mm_struct *mm,
return __get_user_pages(tsk, mm, start, 1, flags, page, NULL, NULL);
}
-int kvm_get_user_page_io(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long addr, bool write_fault,
- struct page **pagep)
-{
- int npages;
- int locked = 1;
- int flags = FOLL_TOUCH | FOLL_HWPOISON |
- (pagep ? FOLL_GET : 0) |
- (write_fault ? FOLL_WRITE : 0);
-
- /*
- * If retrying the fault, we get here *not* having allowed the filemap
- * to wait on the page lock. We should now allow waiting on the IO with
- * the mmap semaphore released.
- */
- down_read(&mm->mmap_sem);
- npages = __get_user_pages(tsk, mm, addr, 1, flags, pagep, NULL,
- &locked);
- if (!locked) {
- VM_BUG_ON(npages);
-
- if (!pagep)
- return 0;
-
- /*
- * The previous call has now waited on the IO. Now we can
- * retry and complete. Pass TRIED to ensure we do not re
- * schedule async IO (see e.g. filemap_fault).
- */
- down_read(&mm->mmap_sem);
- npages = __get_user_pages(tsk, mm, addr, 1, flags | FOLL_TRIED,
- pagep, NULL, NULL);
- }
- up_read(&mm->mmap_sem);
- return npages;
-}
-
static inline int check_user_page_hwpoison(unsigned long addr)
{
int rc, flags = FOLL_TOUCH | FOLL_HWPOISON | FOLL_WRITE;
@@ -1227,15 +1190,10 @@ static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
npages = get_user_page_nowait(current, current->mm,
addr, write_fault, page);
up_read(&current->mm->mmap_sem);
- } else {
- /*
- * By now we have tried gup_fast, and possibly async_pf, and we
- * are certainly not atomic. Time to retry the gup, allowing
- * mmap semaphore to be relinquished in the case of IO.
- */
- npages = kvm_get_user_page_io(current, current->mm, addr,
- write_fault, page);
- }
+ } else
+ npages = __get_user_pages_unlocked(current, current->mm, addr, 1,
+ write_fault, 0, page,
+ FOLL_TOUCH|FOLL_HWPOISON);
if (npages != 1)
return npages;