bcache: Stripe size isn't necessarily a power of two

Originally I got this right... except that the divides didn't use
do_div(), which broke 32 bit kernels. When I went to fix that, I forgot
that the raid stripe size usually isn't a power of two... doh

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

5 files changed, 27 insertions, 25 deletions

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 578615604be5..6e836f22f276 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -437,7 +437,7 @@ struct bcache_device {
         int                     flush_done;
 
         uint64_t                nr_stripes;
-        unsigned                stripe_size_bits;
+        unsigned                stripe_size;
         atomic_t                *stripe_sectors_dirty;
 
         unsigned long           sectors_dirty_last;
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 74f2e902d876..d3169c0652f8 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -761,11 +761,10 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
         struct request_queue *q;
         size_t n;
 
-        if (!d->stripe_size_bits)
-                d->stripe_size_bits = 31;
+        if (!d->stripe_size)
+                d->stripe_size = 1 << 31;
 
-        d->nr_stripes = round_up(sectors, 1 << d->stripe_size_bits) >>
-                d->stripe_size_bits;
+        d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
 
         if (!d->nr_stripes || d->nr_stripes > SIZE_MAX / sizeof(atomic_t))
                 return -ENOMEM;
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 4211d82179fc..b3a66f17231d 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -157,7 +157,7 @@ SHOW(__bch_cached_dev)
         sysfs_hprint(dirty_data,
                      bcache_dev_sectors_dirty(&dc->disk) << 9);
 
-        sysfs_hprint(stripe_size,       (1 << dc->disk.stripe_size_bits) << 9);
+        sysfs_hprint(stripe_size,       dc->disk.stripe_size << 9);
         var_printf(partial_stripes_expensive,   "%u");
 
         var_printf(sequential_merge,    "%i");
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index ba3ee48320f2..b842fbfbf1db 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -114,25 +114,25 @@ static bool dirty_pred(struct keybuf *buf, struct bkey *k)
 
 static bool dirty_full_stripe_pred(struct keybuf *buf, struct bkey *k)
 {
-        uint64_t stripe;
+        uint64_t stripe = KEY_START(k);
         unsigned nr_sectors = KEY_SIZE(k);
         struct cached_dev *dc = container_of(buf, struct cached_dev,
                                              writeback_keys);
-        unsigned stripe_size = 1 << dc->disk.stripe_size_bits;
 
         if (!KEY_DIRTY(k))
                 return false;
 
-        stripe = KEY_START(k) >> dc->disk.stripe_size_bits;
-        while (1) {
-                if (atomic_read(dc->disk.stripe_sectors_dirty + stripe) !=
-                    stripe_size)
-                        return false;
+        do_div(stripe, dc->disk.stripe_size);
 
-                if (nr_sectors <= stripe_size)
+        while (1) {
+                if (atomic_read(dc->disk.stripe_sectors_dirty + stripe) ==
+                    dc->disk.stripe_size)
                         return true;
 
-                nr_sectors -= stripe_size;
+                if (nr_sectors <= dc->disk.stripe_size)
+                        return false;
+
+                nr_sectors -= dc->disk.stripe_size;
                 stripe++;
         }
 }
@@ -186,11 +186,12 @@ static void refill_dirty(struct closure *cl)
 
                 for (i = 0; i < dc->disk.nr_stripes; i++)
                         if (atomic_read(dc->disk.stripe_sectors_dirty + i) ==
-                            1 << dc->disk.stripe_size_bits)
+                            dc->disk.stripe_size)
                                 goto full_stripes;
 
                 goto normal_refill;
 full_stripes:
+                searched_from_start = false;    /* not searching entire btree */
                 bch_refill_keybuf(dc->disk.c, buf, &end,
                                   dirty_full_stripe_pred);
         } else {
@@ -252,19 +253,19 @@ void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned inode,
                                   uint64_t offset, int nr_sectors)
 {
         struct bcache_device *d = c->devices[inode];
-        unsigned stripe_size, stripe_offset;
-        uint64_t stripe;
+        unsigned stripe_offset;
+        uint64_t stripe = offset;
 
         if (!d)
                 return;
 
-        stripe_size = 1 << d->stripe_size_bits;
-        stripe = offset >> d->stripe_size_bits;
-        stripe_offset = offset & (stripe_size - 1);
+        do_div(stripe, d->stripe_size);
+
+        stripe_offset = offset & (d->stripe_size - 1);
 
         while (nr_sectors) {
                 int s = min_t(unsigned, abs(nr_sectors),
-                              stripe_size - stripe_offset);
+                              d->stripe_size - stripe_offset);
 
                 if (nr_sectors < 0)
                         s = -s;
diff --git a/drivers/md/bcache/writeback.h b/drivers/md/bcache/writeback.h
index c91f61bb95b6..34961888b5a9 100644
--- a/drivers/md/bcache/writeback.h
+++ b/drivers/md/bcache/writeback.h
@@ -18,16 +18,18 @@ static inline bool bcache_dev_stripe_dirty(struct bcache_device *d,
                                            uint64_t offset,
                                            unsigned nr_sectors)
 {
-        uint64_t stripe = offset >> d->stripe_size_bits;
+        uint64_t stripe = offset;
+
+        do_div(stripe, d->stripe_size);
 
         while (1) {
                 if (atomic_read(d->stripe_sectors_dirty + stripe))
                         return true;
 
-                if (nr_sectors <= 1 << d->stripe_size_bits)
+                if (nr_sectors <= d->stripe_size)
                         return false;
 
-                nr_sectors -= 1 << d->stripe_size_bits;
+                nr_sectors -= d->stripe_size;
                 stripe++;
         }
 }