[PATCH] IB/mthca: encapsulate MTT buddy allocator

Encapsulate the buddy allocator used for MTT segments.  This cleans up the
code and also gets us ready to add FMR support.

Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 95 insertions, 74 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_dev.h b/drivers/infiniband/hw/mthca/mthca_dev.h
index d4bd9aa232b1..1faaf542a4e1 100644
--- a/drivers/infiniband/hw/mthca/mthca_dev.h
+++ b/drivers/infiniband/hw/mthca/mthca_dev.h
@@ -170,10 +170,15 @@ struct mthca_pd_table {
         struct mthca_alloc alloc;
 };
 
+struct mthca_buddy {
+        unsigned long **bits;
+        int             max_order;
+        spinlock_t      lock;
+};
+
 struct mthca_mr_table {
         struct mthca_alloc      mpt_alloc;
-        int                     max_mtt_order;
-        unsigned long         **mtt_buddy;
+        struct mthca_buddy      mtt_buddy;
         u64                     mtt_base;
         struct mthca_icm_table *mtt_table;
         struct mthca_icm_table *mpt_table;
diff --git a/drivers/infiniband/hw/mthca/mthca_mr.c b/drivers/infiniband/hw/mthca/mthca_mr.c
index 5cde296b4065..6a127a7aca57 100644
--- a/drivers/infiniband/hw/mthca/mthca_mr.c
+++ b/drivers/infiniband/hw/mthca/mthca_mr.c
@@ -72,60 +72,108 @@ struct mthca_mpt_entry {
  * through the bitmaps)
  */
 
-static u32 __mthca_alloc_mtt(struct mthca_dev *dev, int order)
+static u32 mthca_buddy_alloc(struct mthca_buddy *buddy, int order)
 {
         int o;
         int m;
         u32 seg;
 
-        spin_lock(&dev->mr_table.mpt_alloc.lock);
+        spin_lock(&buddy->lock);
 
-        for (o = order; o <= dev->mr_table.max_mtt_order; ++o) {
-                m = 1 << (dev->mr_table.max_mtt_order - o);
-                seg = find_first_bit(dev->mr_table.mtt_buddy[o], m);
+        for (o = order; o <= buddy->max_order; ++o) {
+                m = 1 << (buddy->max_order - o);
+                seg = find_first_bit(buddy->bits[o], m);
                 if (seg < m)
                         goto found;
         }
 
-        spin_unlock(&dev->mr_table.mpt_alloc.lock);
+        spin_unlock(&buddy->lock);
         return -1;
 
  found:
-        clear_bit(seg, dev->mr_table.mtt_buddy[o]);
+        clear_bit(seg, buddy->bits[o]);
 
         while (o > order) {
                 --o;
                 seg <<= 1;
-                set_bit(seg ^ 1, dev->mr_table.mtt_buddy[o]);
+                set_bit(seg ^ 1, buddy->bits[o]);
         }
 
-        spin_unlock(&dev->mr_table.mpt_alloc.lock);
+        spin_unlock(&buddy->lock);
 
         seg <<= order;
 
         return seg;
 }
 
-static void __mthca_free_mtt(struct mthca_dev *dev, u32 seg, int order)
+static void mthca_buddy_free(struct mthca_buddy *buddy, u32 seg, int order)
 {
         seg >>= order;
 
-        spin_lock(&dev->mr_table.mpt_alloc.lock);
+        spin_lock(&buddy->lock);
 
-        while (test_bit(seg ^ 1, dev->mr_table.mtt_buddy[order])) {
-                clear_bit(seg ^ 1, dev->mr_table.mtt_buddy[order]);
+        while (test_bit(seg ^ 1, buddy->bits[order])) {
+                clear_bit(seg ^ 1, buddy->bits[order]);
                 seg >>= 1;
                 ++order;
         }
 
-        set_bit(seg, dev->mr_table.mtt_buddy[order]);
+        set_bit(seg, buddy->bits[order]);
 
-        spin_unlock(&dev->mr_table.mpt_alloc.lock);
+        spin_unlock(&buddy->lock);
 }
 
-static u32 mthca_alloc_mtt(struct mthca_dev *dev, int order)
+static int __devinit mthca_buddy_init(struct mthca_buddy *buddy, int max_order)
 {
-        u32 seg = __mthca_alloc_mtt(dev, order);
+        int i, s;
+
+        buddy->max_order = max_order;
+        spin_lock_init(&buddy->lock);
+
+        buddy->bits = kmalloc((buddy->max_order + 1) * sizeof (long *),
+                              GFP_KERNEL);
+        if (!buddy->bits)
+                goto err_out;
+
+        memset(buddy->bits, 0, (buddy->max_order + 1) * sizeof (long *));
+
+        for (i = 0; i <= buddy->max_order; ++i) {
+                s = BITS_TO_LONGS(1 << (buddy->max_order - i));
+                buddy->bits[i] = kmalloc(s * sizeof (long), GFP_KERNEL);
+                if (!buddy->bits[i])
+                        goto err_out_free;
+                bitmap_zero(buddy->bits[i],
+                            1 << (buddy->max_order - i));
+        }
+
+        set_bit(0, buddy->bits[buddy->max_order]);
+
+        return 0;
+
+err_out_free:
+        for (i = 0; i <= buddy->max_order; ++i)
+                kfree(buddy->bits[i]);
+
+        kfree(buddy->bits);
+
+err_out:
+        return -ENOMEM;
+}
+
+static void __devexit mthca_buddy_cleanup(struct mthca_buddy *buddy)
+{
+        int i;
+
+        for (i = 0; i <= buddy->max_order; ++i)
+                kfree(buddy->bits[i]);
+
+        kfree(buddy->bits);
+}
+
+static u32 mthca_alloc_mtt(struct mthca_dev *dev, int order,
+                           struct mthca_buddy *buddy)
+{
+        u32 seg = mthca_buddy_alloc(buddy, order);
 
         if (seg == -1)
                 return -1;
@@ -133,16 +181,17 @@ static u32 mthca_alloc_mtt(struct mthca_dev *dev, int order)
         if (dev->hca_type == ARBEL_NATIVE)
                 if (mthca_table_get_range(dev, dev->mr_table.mtt_table, seg,
                                           seg + (1 << order) - 1)) {
-                        __mthca_free_mtt(dev, seg, order);
+                        mthca_buddy_free(buddy, seg, order);
                         seg = -1;
                 }
 
         return seg;
 }
 
-static void mthca_free_mtt(struct mthca_dev *dev, u32 seg, int order)
+static void mthca_free_mtt(struct mthca_dev *dev, u32 seg, int order,
+                           struct mthca_buddy* buddy)
 {
-        __mthca_free_mtt(dev, seg, order);
+        mthca_buddy_free(buddy, seg, order);
 
         if (dev->hca_type == ARBEL_NATIVE)
                 mthca_table_put_range(dev, dev->mr_table.mtt_table, seg,
@@ -268,7 +317,8 @@ int mthca_mr_alloc_phys(struct mthca_dev *dev, u32 pd,
              i <<= 1, ++mr->order)
                 ; /* nothing */
 
-        mr->first_seg = mthca_alloc_mtt(dev, mr->order);
+        mr->first_seg = mthca_alloc_mtt(dev, mr->order,
+                                        &dev->mr_table.mtt_buddy);
         if (mr->first_seg == -1)
                 goto err_out_table;
 
@@ -361,7 +411,7 @@ err_out_mailbox_free:
         kfree(mailbox);
 
 err_out_free_mtt:
-        mthca_free_mtt(dev, mr->first_seg, mr->order);
+        mthca_free_mtt(dev, mr->first_seg, mr->order, &dev->mr_table.mtt_buddy);
 
 err_out_table:
         if (dev->hca_type == ARBEL_NATIVE)
@@ -390,7 +440,7 @@ void mthca_free_mr(struct mthca_dev *dev, struct mthca_mr *mr)
                            status);
 
         if (mr->order >= 0)
-                mthca_free_mtt(dev, mr->first_seg, mr->order);
+                mthca_free_mtt(dev, mr->first_seg, mr->order, &dev->mr_table.mtt_buddy);
 
         if (dev->hca_type == ARBEL_NATIVE)
                 mthca_table_put(dev, dev->mr_table.mpt_table,
@@ -401,7 +451,6 @@ void mthca_free_mr(struct mthca_dev *dev, struct mthca_mr *mr)
 int __devinit mthca_init_mr_table(struct mthca_dev *dev)
 {
         int err;
-        int i, s;
 
         err = mthca_alloc_init(&dev->mr_table.mpt_alloc,
                                dev->limits.num_mpts,
@@ -409,53 +458,24 @@ int __devinit mthca_init_mr_table(struct mthca_dev *dev)
         if (err)
                 return err;
 
-        err = -ENOMEM;
-
-        for (i = 1, dev->mr_table.max_mtt_order = 0;
-             i < dev->limits.num_mtt_segs;
-             i <<= 1, ++dev->mr_table.max_mtt_order)
-                ; /* nothing */
-
-        dev->mr_table.mtt_buddy = kmalloc((dev->mr_table.max_mtt_order + 1) *
-                                          sizeof (long *),
-                                          GFP_KERNEL);
-        if (!dev->mr_table.mtt_buddy)
-                goto err_out;
-
-        for (i = 0; i <= dev->mr_table.max_mtt_order; ++i)
-                dev->mr_table.mtt_buddy[i] = NULL;
-
-        for (i = 0; i <= dev->mr_table.max_mtt_order; ++i) {
-                s = BITS_TO_LONGS(1 << (dev->mr_table.max_mtt_order - i));
-                dev->mr_table.mtt_buddy[i] = kmalloc(s * sizeof (long),
-                                                     GFP_KERNEL);
-                if (!dev->mr_table.mtt_buddy[i])
-                        goto err_out_free;
-                bitmap_zero(dev->mr_table.mtt_buddy[i],
-                            1 << (dev->mr_table.max_mtt_order - i));
-        }
-
-        set_bit(0, dev->mr_table.mtt_buddy[dev->mr_table.max_mtt_order]);
-
-        for (i = 0; i < dev->mr_table.max_mtt_order; ++i)
-                if (1 << i >= dev->limits.reserved_mtts)
-                        break;
-
-        if (i == dev->mr_table.max_mtt_order) {
-                mthca_err(dev, "MTT table of order %d is "
-                          "too small.\n", i);
-                goto err_out_free;
+        err = mthca_buddy_init(&dev->mr_table.mtt_buddy,
+                               fls(dev->limits.num_mtt_segs - 1));
+        if (err)
+                goto err_mtt_buddy;
+
+        if (dev->limits.reserved_mtts) {
+                if (mthca_alloc_mtt(dev, fls(dev->limits.reserved_mtts - 1),
+                                    &dev->mr_table.mtt_buddy) == -1) {
+                        mthca_warn(dev, "MTT table of order %d is too small.\n",
+                                  dev->mr_table.mtt_buddy.max_order);
+                        err = -ENOMEM;
+                        goto err_mtt_buddy;
+                }
         }
 
-        (void) mthca_alloc_mtt(dev, i);
-
         return 0;
 
- err_out_free:
-        for (i = 0; i <= dev->mr_table.max_mtt_order; ++i)
-                kfree(dev->mr_table.mtt_buddy[i]);
-
- err_out:
+err_mtt_buddy:
         mthca_alloc_cleanup(&dev->mr_table.mpt_alloc);
 
         return err;
@@ -463,11 +483,7 @@ int __devinit mthca_init_mr_table(struct mthca_dev *dev)
 
 void __devexit mthca_cleanup_mr_table(struct mthca_dev *dev)
 {
-        int i;
-
         /* XXX check if any MRs are still allocated? */
-        for (i = 0; i <= dev->mr_table.max_mtt_order; ++i)
-                kfree(dev->mr_table.mtt_buddy[i]);
-        kfree(dev->mr_table.mtt_buddy);
+        mthca_buddy_cleanup(&dev->mr_table.mtt_buddy);
         mthca_alloc_cleanup(&dev->mr_table.mpt_alloc);
 }