drivers/md/raid1-10.c

   1 /* Maximum size of each resync request */
   2 #define RESYNC_BLOCK_SIZE (64*1024)
   3 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
   4
   5 /* for managing resync I/O pages */
   6 struct resync_pages {
   7         void            *raid_bio;
   8         struct page     *pages[RESYNC_PAGES];
   9 };
  10
  11 static inline int resync_alloc_pages(struct resync_pages *rp,
  12                                      gfp_t gfp_flags)
  13 {
  14         int i;
  15
  16         for (i = 0; i < RESYNC_PAGES; i++) {
  17                 rp->pages[i] = alloc_page(gfp_flags);
  18                 if (!rp->pages[i])
  19                         goto out_free;
  20         }
  21
  22         return 0;
  23
  24 out_free:
  25         while (--i >= 0)
  26                 put_page(rp->pages[i]);
  27         return -ENOMEM;
  28 }
  29
  30 static inline void resync_free_pages(struct resync_pages *rp)
  31 {
  32         int i;
  33
  34         for (i = 0; i < RESYNC_PAGES; i++)
  35                 put_page(rp->pages[i]);
  36 }
  37
  38 static inline void resync_get_all_pages(struct resync_pages *rp)
  39 {
  40         int i;
  41
  42         for (i = 0; i < RESYNC_PAGES; i++)
  43                 get_page(rp->pages[i]);
  44 }
  45
  46 static inline struct page *resync_fetch_page(struct resync_pages *rp,
  47                                              unsigned idx)
  48 {
  49         if (WARN_ON_ONCE(idx >= RESYNC_PAGES))
  50                 return NULL;
  51         return rp->pages[idx];
  52 }
  53
  54 /*
  55  * 'strct resync_pages' stores actual pages used for doing the resync
  56  *  IO, and it is per-bio, so make .bi_private points to it.
  57  */
  58 static inline struct resync_pages *get_resync_pages(struct bio *bio)
  59 {
  60         return bio->bi_private;
  61 }
  62
  63 /* generally called after bio_reset() for reseting bvec */
  64 static void md_bio_reset_resync_pages(struct bio *bio, struct resync_pages *rp,
  65                                int size)
  66 {
  67         int idx = 0;
  68
  69         /* initialize bvec table again */
  70         do {
  71                 struct page *page = resync_fetch_page(rp, idx);
  72                 int len = min_t(int, size, PAGE_SIZE);
  73
  74                 /*
  75                  * won't fail because the vec table is big
  76                  * enough to hold all these pages
  77                  */
  78                 bio_add_page(bio, page, len, 0);
  79                 size -= len;
  80         } while (idx++ < RESYNC_PAGES && size > 0);
  81 }