bcache: Better full stripe scanning

The old scanning-by-stripe code burned too much CPU, this should be
better.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 4813ef67cef5..43fcfe38be11 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -738,6 +738,10 @@ static void bcache_device_free(struct bcache_device *d)
                 mempool_destroy(d->unaligned_bvec);
         if (d->bio_split)
                 bioset_free(d->bio_split);
+        if (is_vmalloc_addr(d->full_dirty_stripes))
+                vfree(d->full_dirty_stripes);
+        else
+                kfree(d->full_dirty_stripes);
         if (is_vmalloc_addr(d->stripe_sectors_dirty))
                 vfree(d->stripe_sectors_dirty);
         else
@@ -757,8 +761,12 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
 
         d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
 
-        if (!d->nr_stripes || d->nr_stripes > SIZE_MAX / sizeof(atomic_t))
+        if (!d->nr_stripes ||
+            d->nr_stripes > INT_MAX ||
+            d->nr_stripes > SIZE_MAX / sizeof(atomic_t)) {
+                pr_err("nr_stripes too large");
                 return -ENOMEM;
+        }
 
         n = d->nr_stripes * sizeof(atomic_t);
         d->stripe_sectors_dirty = n < PAGE_SIZE << 6
@@ -767,6 +775,13 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
         if (!d->stripe_sectors_dirty)
                 return -ENOMEM;
 
+        n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
+        d->full_dirty_stripes = n < PAGE_SIZE << 6
+                ? kzalloc(n, GFP_KERNEL)
+                : vzalloc(n);
+        if (!d->full_dirty_stripes)
+                return -ENOMEM;
+
         if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
             !(d->unaligned_bvec = mempool_create_kmalloc_pool(1,
                                 sizeof(struct bio_vec) * BIO_MAX_PAGES)) ||