[PATCH V6 3/7] vfio/type1: track locked_vm per dma

[Steve Sistare <steven.sistare@oracle.com>]

Track locked_vm per dma struct, and create a new subroutine, both for use
in a subsequent patch.  No functional change.

Fixes: c3cbab24db38 ("vfio/type1: implement interfaces to update vaddr")
Cc: stable@vger.kernel.org
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 drivers/vfio/vfio_iommu_type1.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 71f980b..889e920 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -101,6 +101,7 @@ struct vfio_dma {
 	struct rb_root		pfn_list;	/* Ex-user pinned pfn list */
 	unsigned long		*bitmap;
 	struct mm_struct	*mm;
+	long			locked_vm;
 };
 
 struct vfio_batch {
@@ -413,22 +414,21 @@ static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn)
 	return ret;
 }
 
-static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async)
+static int task_lock_acct(struct task_struct *task, struct mm_struct *mm,
+			  bool lock_cap, long npage, bool async)
 {
-	struct mm_struct *mm;
 	int ret;
 
 	if (!npage)
 		return 0;
 
-	mm = dma->mm;
 	if (async && !mmget_not_zero(mm))
 		return -ESRCH; /* process exited */
 
 	ret = mmap_write_lock_killable(mm);
 	if (!ret) {
-		ret = __account_locked_vm(mm, abs(npage), npage > 0, dma->task,
-					  dma->lock_cap);
+		ret = __account_locked_vm(mm, abs(npage), npage > 0, task,
+					  lock_cap);
 		mmap_write_unlock(mm);
 	}
 
@@ -438,6 +438,16 @@ static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async)
 	return ret;
 }
 
+static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async)
+{
+	int ret;
+
+	ret = task_lock_acct(dma->task, dma->mm, dma->lock_cap, npage, async);
+	if (!ret)
+		dma->locked_vm += npage;
+	return ret;
+}
+
 /*
  * Some mappings aren't backed by a struct page, for example an mmap'd
  * MMIO range for our own or another device.  These use a different
-- 
1.8.3.1