This simplifies the code a little bit, both now and for later patches.
The inline function idal_nr_words() performs the same function that
we were doing here, which is figure out how many pages a given
contiguous piece of memory might span. (That is, len/4K if aligned
on a 4K page, or len/4K + 1 if not.) So we'll use this routine as
a matter of convenience, even though we're not building an IDAL.
Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx>
---
drivers/s390/cio/vfio_ccw_cp.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index efc30152a89a..5f16aa88c629 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -54,7 +54,7 @@ struct ccwchain {
* @pa: pfn_array on which to perform the operation
* @mdev: the mediated device to perform pin/unpin operations
* @iova: target guest physical address
- * @len: number of bytes that should be pinned from @iova
+ * @len: number of pages that should be pinned from @iova
*
* Attempt to allocate memory for PFNs, and pin user pages in memory.
*
@@ -80,10 +80,7 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev,
return -EINVAL;
pa->pa_iova = iova;
-
- pa->pa_nr = ((iova & ~PAGE_MASK) + len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
- if (!pa->pa_nr)
- return -EINVAL;
+ pa->pa_nr = len;
pa->pa_iova_pfn = kcalloc(pa->pa_nr,
sizeof(*pa->pa_iova_pfn) +
@@ -209,7 +206,8 @@ static long copy_from_iova(struct device *mdev,
int i, ret;
unsigned long l, m;
- ret = pfn_array_alloc_pin(&pa, mdev, iova, n);
+ ret = pfn_array_alloc_pin(&pa, mdev, iova,
+ idal_nr_words((void *)(iova), n));
if (ret <= 0)
return ret;
--
2.16.4
