1 files changed, 81 insertions, 0 deletions

diff --git a/drivers/md/raid1-10.c b/drivers/md/raid1-10.c
new file mode 100644
index 000000000000..9f2670b45f31
--- /dev/null
+++ b/drivers/md/raid1-10.c
@@ -0,0 +1,81 @@
+/* Maximum size of each resync request */
+#define RESYNC_BLOCK_SIZE (64*1024)
+#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
+
+/* for managing resync I/O pages */
+struct resync_pages {
+        void            *raid_bio;
+        struct page     *pages[RESYNC_PAGES];
+};
+
+static inline int resync_alloc_pages(struct resync_pages *rp,
+                                     gfp_t gfp_flags)
+{
+        int i;
+
+        for (i = 0; i < RESYNC_PAGES; i++) {
+                rp->pages[i] = alloc_page(gfp_flags);
+                if (!rp->pages[i])
+                        goto out_free;
+        }
+
+        return 0;
+
+out_free:
+        while (--i >= 0)
+                put_page(rp->pages[i]);
+        return -ENOMEM;
+}
+
+static inline void resync_free_pages(struct resync_pages *rp)
+{
+        int i;
+
+        for (i = 0; i < RESYNC_PAGES; i++)
+                put_page(rp->pages[i]);
+}
+
+static inline void resync_get_all_pages(struct resync_pages *rp)
+{
+        int i;
+
+        for (i = 0; i < RESYNC_PAGES; i++)
+                get_page(rp->pages[i]);
+}
+
+static inline struct page *resync_fetch_page(struct resync_pages *rp,
+                                             unsigned idx)
+{
+        if (WARN_ON_ONCE(idx >= RESYNC_PAGES))
+                return NULL;
+        return rp->pages[idx];
+}
+
+/*
+ * 'strct resync_pages' stores actual pages used for doing the resync
+ *  IO, and it is per-bio, so make .bi_private points to it.
+ */
+static inline struct resync_pages *get_resync_pages(struct bio *bio)
+{
+        return bio->bi_private;
+}
+
+/* generally called after bio_reset() for reseting bvec */
+static void md_bio_reset_resync_pages(struct bio *bio, struct resync_pages *rp,
+                               int size)
+{
+        int idx = 0;
+
+        /* initialize bvec table again */
+        do {
+                struct page *page = resync_fetch_page(rp, idx);
+                int len = min_t(int, size, PAGE_SIZE);
+
+                /*
+                 * won't fail because the vec table is big
+                 * enough to hold all these pages
+                 */
+                bio_add_page(bio, page, len, 0);
+                size -= len;
+        } while (idx++ < RESYNC_PAGES && size > 0);
+}