md/raid10: share pages between read and write bio's during recovery

[mirror_ubuntu-bionic-kernel.git] / drivers / md / raid10.c

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index e434f1e8d22331c2f4a4e8ccaa1a9c2fb386e21e..3715e220e5e08aed5f21907f891b1f19535f2c33 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -123,7 +123,14 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
        for (j = 0 ; j < nalloc; j++) {
                bio = r10_bio->devs[j].bio;
                for (i = 0; i < RESYNC_PAGES; i++) {
-                       page = alloc_page(gfp_flags);
+                       if (j == 1 && !test_bit(MD_RECOVERY_SYNC,
+                                               &conf->mddev->recovery)) {
+                               /* we can share bv_page's during recovery */
+                               struct bio *rbio = r10_bio->devs[0].bio;
+                               page = rbio->bi_io_vec[i].bv_page;
+                               get_page(page);
+                       } else
+                               page = alloc_page(gfp_flags);
                        if (unlikely(!page))
                                goto out_free_pages;
 
@@ -1360,20 +1367,14 @@ done:
 static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
 {
        conf_t *conf = mddev->private;
-       int i, d;
-       struct bio *bio, *wbio;
-
+       int d;
+       struct bio *wbio;
 
-       /* move the pages across to the second bio
+       /*
+        * share the pages with the first bio
         * and submit the write request
         */
-       bio = r10_bio->devs[0].bio;
        wbio = r10_bio->devs[1].bio;
-       for (i=0; i < wbio->bi_vcnt; i++) {
-               struct page *p = bio->bi_io_vec[i].bv_page;
-               bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page;
-               wbio->bi_io_vec[i].bv_page = p;
-       }
        d = r10_bio->devs[1].devnum;
 
        atomic_inc(&conf->mirrors[d].rdev->nr_pending);