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-rw-r--r--drivers/md/raid1-10.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/drivers/md/raid1-10.c b/drivers/md/raid1-10.c
new file mode 100644
index 000000000..e0c8ac814
--- /dev/null
+++ b/drivers/md/raid1-10.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Maximum size of each resync request */
+#define RESYNC_BLOCK_SIZE (64*1024)
+#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
+
+/*
+ * Number of guaranteed raid bios in case of extreme VM load:
+ */
+#define NR_RAID_BIOS 256
+
+/* when we get a read error on a read-only array, we redirect to another
+ * device without failing the first device, or trying to over-write to
+ * correct the read error. To keep track of bad blocks on a per-bio
+ * level, we store IO_BLOCKED in the appropriate 'bios' pointer
+ */
+#define IO_BLOCKED ((struct bio *)1)
+/* When we successfully write to a known bad-block, we need to remove the
+ * bad-block marking which must be done from process context. So we record
+ * the success by setting devs[n].bio to IO_MADE_GOOD
+ */
+#define IO_MADE_GOOD ((struct bio *)2)
+
+#define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
+
+/* for managing resync I/O pages */
+struct resync_pages {
+ void *raid_bio;
+ struct page *pages[RESYNC_PAGES];
+};
+
+struct raid1_plug_cb {
+ struct blk_plug_cb cb;
+ struct bio_list pending;
+};
+
+static void rbio_pool_free(void *rbio, void *data)
+{
+ kfree(rbio);
+}
+
+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);
+}
+
+
+static inline void raid1_submit_write(struct bio *bio)
+{
+ struct md_rdev *rdev = (void *)bio->bi_bdev;
+
+ bio->bi_next = NULL;
+ bio_set_dev(bio, rdev->bdev);
+ if (test_bit(Faulty, &rdev->flags))
+ bio_io_error(bio);
+ else if (unlikely(bio_op(bio) == REQ_OP_DISCARD &&
+ !bdev_max_discard_sectors(bio->bi_bdev)))
+ /* Just ignore it */
+ bio_endio(bio);
+ else
+ submit_bio_noacct(bio);
+}
+
+static inline bool raid1_add_bio_to_plug(struct mddev *mddev, struct bio *bio,
+ blk_plug_cb_fn unplug)
+{
+ struct raid1_plug_cb *plug = NULL;
+ struct blk_plug_cb *cb;
+
+ /*
+ * If bitmap is not enabled, it's safe to submit the io directly, and
+ * this can get optimal performance.
+ */
+ if (!md_bitmap_enabled(mddev->bitmap)) {
+ raid1_submit_write(bio);
+ return true;
+ }
+
+ cb = blk_check_plugged(unplug, mddev, sizeof(*plug));
+ if (!cb)
+ return false;
+
+ plug = container_of(cb, struct raid1_plug_cb, cb);
+ bio_list_add(&plug->pending, bio);
+
+ return true;
+}