1 files changed, 5 insertions, 4 deletions

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 1bcd208c459f..9734994cba1e 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -163,6 +163,7 @@ struct ubd {
         struct scatterlist sg[MAX_SG];
         struct request *request;
         int start_sg, end_sg;
+        sector_t rq_pos;
 };
 
 #define DEFAULT_COW { \
@@ -187,6 +188,7 @@ struct ubd {
         .request =              NULL, \
         .start_sg =             0, \
         .end_sg =               0, \
+        .rq_pos =               0, \
 }
 
 /* Protected by ubd_lock */
@@ -1228,7 +1230,6 @@ static void do_ubd_request(struct request_queue *q)
 {
         struct io_thread_req *io_req;
         struct request *req;
-        sector_t sector;
         int n;
 
         while(1){
@@ -1239,12 +1240,12 @@ static void do_ubd_request(struct request_queue *q)
                                 return;
 
                         dev->request = req;
+                        dev->rq_pos = blk_rq_pos(req);
                         dev->start_sg = 0;
                         dev->end_sg = blk_rq_map_sg(q, req, dev->sg);
                 }
 
                 req = dev->request;
-                sector = blk_rq_pos(req);
                 while(dev->start_sg < dev->end_sg){
                         struct scatterlist *sg = &dev->sg[dev->start_sg];
 
@@ -1256,10 +1257,9 @@ static void do_ubd_request(struct request_queue *q)
                                 return;
                         }
                         prepare_request(req, io_req,
-                                        (unsigned long long)sector << 9,
+                                        (unsigned long long)dev->rq_pos << 9,
                                         sg->offset, sg->length, sg_page(sg));
 
-                        sector += sg->length >> 9;
                         n = os_write_file(thread_fd, &io_req,
                                           sizeof(struct io_thread_req *));
                         if(n != sizeof(struct io_thread_req *)){
@@ -1272,6 +1272,7 @@ static void do_ubd_request(struct request_queue *q)
                                 return;
                         }
 
+                        dev->rq_pos += sg->length >> 9;
                         dev->start_sg++;
                 }
                 dev->end_sg = 0;