2 files changed, 10 insertions, 2 deletions

diff --git a/include/linux/swap.h b/include/linux/swap.h
index fe79f44c858e..cbf7fbed3dfd 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -122,6 +122,7 @@ enum {
         SWP_WRITEOK     = (1 << 1),     /* ok to write to this swap?    */
         SWP_DISCARDABLE = (1 << 2),     /* blkdev supports discard */
         SWP_DISCARDING  = (1 << 3),     /* now discarding a free cluster */
+        SWP_SOLIDSTATE  = (1 << 4),     /* blkdev seeks are cheap */
                                         /* add others here before... */
         SWP_SCANNING    = (1 << 8),     /* refcount in scan_swap_map */
 };
diff --git a/mm/swapfile.c b/mm/swapfile.c
index ca75b9e7c09f..b0f56603b9be 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -16,6 +16,7 @@
 #include <linux/namei.h>
 #include <linux/shm.h>
 #include <linux/blkdev.h>
+#include <linux/random.h>
 #include <linux/writeback.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
@@ -1806,6 +1807,11 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
                 goto bad_swap;
         }
 
+        if (blk_queue_nonrot(bdev_get_queue(p->bdev))) {
+                p->flags |= SWP_SOLIDSTATE;
+                srandom32((u32)get_seconds());
+                p->cluster_next = 1 + (random32() % p->highest_bit);
+        }
         if (discard_swap(p) == 0)
                 p->flags |= SWP_DISCARDABLE;
 
@@ -1822,10 +1828,11 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
         total_swap_pages += nr_good_pages;
 
         printk(KERN_INFO "Adding %uk swap on %s.  "
-                        "Priority:%d extents:%d across:%lluk%s\n",
+                        "Priority:%d extents:%d across:%lluk %s%s\n",
                 nr_good_pages<<(PAGE_SHIFT-10), name, p->prio,
                 nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10),
-                (p->flags & SWP_DISCARDABLE) ? " D" : "");
+                (p->flags & SWP_SOLIDSTATE) ? "SS" : "",
+                (p->flags & SWP_DISCARDABLE) ? "D" : "");
 
         /* insert swap space into swap_list: */
         prev = -1;