[SCSI] st: add struct rq_map_data support

This adds struct rq_map_data and the array of pointers to store
fragment buffers to struct st_buffer.

This patch doesn't remove st_buf_fragment but the latter patch does.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Kai Makisara <Kai.Makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

2 files changed, 13 insertions, 0 deletions

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 3984cd82fe10..9d9e4b90f23b 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -3723,6 +3723,12 @@ static struct st_buffer *
         tb->buffer_size = got;
         sg_init_table(tb->sg, max_sg);
 
+        tb->reserved_pages = kzalloc(max_sg * sizeof(struct page *), priority);
+        if (!tb->reserved_pages) {
+                kfree(tb);
+                return NULL;
+        }
+
         return tb;
 }
 
@@ -3771,9 +3777,11 @@ static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dm
                 STbuffer->buffer_size = got;
                 if (STbuffer->cleared)
                         memset(page_address(STbuffer->frp[segs].page), 0, b_size);
+                STbuffer->reserved_pages[segs] = STbuffer->frp[segs].page;
                 segs++;
         }
         STbuffer->b_data = page_address(STbuffer->frp[0].page);
+        STbuffer->map_data.page_order = order;
 
         return 1;
 }
@@ -3803,6 +3811,8 @@ static void normalize_buffer(struct st_buffer * STbuffer)
         STbuffer->frp_segs = STbuffer->orig_frp_segs;
         STbuffer->frp_sg_current = 0;
         STbuffer->sg_segs = 0;
+        STbuffer->map_data.page_order = 0;
+        STbuffer->map_data.offset = 0;
 }
 
 
@@ -4282,6 +4292,7 @@ static void scsi_tape_release(struct kref *kref)
         if (tpnt->buffer) {
                 tpnt->buffer->orig_frp_segs = 0;
                 normalize_buffer(tpnt->buffer);
+                kfree(tpnt->buffer->reserved_pages);
                 kfree(tpnt->buffer);
         }
 
diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h
index b92712f95931..74748abe8246 100644
--- a/drivers/scsi/st.h
+++ b/drivers/scsi/st.h
@@ -44,6 +44,8 @@ struct st_buffer {
         int syscall_result;
         struct st_request *last_SRpnt;
         struct st_cmdstatus cmdstat;
+        struct page **reserved_pages;
+        struct rq_map_data map_data;
         unsigned char *b_data;
         unsigned short use_sg;  /* zero or max number of s/g segments for this adapter */
         unsigned short sg_segs;         /* number of segments in s/g list */