[PATCH v2 1/3] tcm_vhost: Introduce iov_num_pages

[Asias He <asias@redhat.com>]

Add a helper to calculate the number of pages needed for a iov entry.

Signed-off-by: Asias He <asias@redhat.com>
---
 drivers/vhost/tcm_vhost.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index 3720604..ca35c16 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -77,6 +77,12 @@ static struct workqueue_struct *tcm_vhost_workqueue;
 static DEFINE_MUTEX(tcm_vhost_mutex);
 static LIST_HEAD(tcm_vhost_list);
 
+static inline int iov_num_pages(struct iovec *iov)
+{
+	return (PAGE_ALIGN((unsigned long)iov->iov_base + iov->iov_len) -
+	       ((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT;
+}
+
 static int tcm_vhost_check_true(struct se_portal_group *se_tpg)
 {
 	return 1;
-- 
1.8.1