nilfs2: do not call nilfs_mdt_bgl_lock() needlessly

In the bitmap based allocator implementation, nilfs_mdt_bgl_lock() helper
is frequently used to get a spinlock protecting a target block group.
This reduces its usage and simplifies arguments of some related functions
by directly passing a pointer to the spinlock.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
index afe9836..ff0d62c 100644 (file)
--- a/fs/nilfs2/alloc.c
+++ b/fs/nilfs2/alloc.c
@@ -133,38 +133,34 @@ nilfs_palloc_bitmap_blkoff(const struct inode *inode, unsigned long group)
 
 /**
  * nilfs_palloc_group_desc_nfrees - get the number of free entries in a group
- * @inode: inode of metadata file using this allocator
- * @group: group number
  * @desc: pointer to descriptor structure for the group
+ * @lock: spin lock protecting @desc
  */
 static unsigned long
-nilfs_palloc_group_desc_nfrees(struct inode *inode, unsigned long group,
-                              const struct nilfs_palloc_group_desc *desc)
+nilfs_palloc_group_desc_nfrees(const struct nilfs_palloc_group_desc *desc,
+                              spinlock_t *lock)
 {
        unsigned long nfree;
 
-       spin_lock(nilfs_mdt_bgl_lock(inode, group));
+       spin_lock(lock);
        nfree = le32_to_cpu(desc->pg_nfrees);
-       spin_unlock(nilfs_mdt_bgl_lock(inode, group));
+       spin_unlock(lock);
        return nfree;
 }
 
 /**
  * nilfs_palloc_group_desc_add_entries - adjust count of free entries
- * @inode: inode of metadata file using this allocator
- * @group: group number
  * @desc: pointer to descriptor structure for the group
+ * @lock: spin lock protecting @desc
  * @n: delta to be added
  */
 static void
-nilfs_palloc_group_desc_add_entries(struct inode *inode,
-                                   unsigned long group,
-                                   struct nilfs_palloc_group_desc *desc,
-                                   u32 n)
+nilfs_palloc_group_desc_add_entries(struct nilfs_palloc_group_desc *desc,
+                                   spinlock_t *lock, u32 n)
 {
-       spin_lock(nilfs_mdt_bgl_lock(inode, group));
+       spin_lock(lock);
        le32_add_cpu(&desc->pg_nfrees, n);
-       spin_unlock(nilfs_mdt_bgl_lock(inode, group));
+       spin_unlock(lock);
 }
 
 /**
@@ -332,17 +328,15 @@ void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
 
 /**
  * nilfs_palloc_find_available_slot - find available slot in a group
- * @inode: inode of metadata file using this allocator
- * @group: group number
- * @target: offset number of an entry in the group (start point)
  * @bitmap: bitmap of the group
+ * @target: offset number of an entry in the group (start point)
  * @bsize: size in bits
+ * @lock: spin lock protecting @bitmap
  */
-static int nilfs_palloc_find_available_slot(struct inode *inode,
-                                           unsigned long group,
+static int nilfs_palloc_find_available_slot(unsigned char *bitmap,
                                            unsigned long target,
-                                           unsigned char *bitmap,
-                                           int bsize)
+                                           int bsize,
+                                           spinlock_t *lock)
 {
        int curr, pos, end, i;
 
@@ -351,12 +345,11 @@ static int nilfs_palloc_find_available_slot(struct inode *inode,
                if (end > bsize)
                        end = bsize;
                pos = nilfs_find_next_zero_bit(bitmap, end, target);
-               if (pos < end &&
-                   !nilfs_set_bit_atomic(
-                           nilfs_mdt_bgl_lock(inode, group), pos, bitmap))
+               if (pos < end && !nilfs_set_bit_atomic(lock, pos, bitmap))
                        return pos;
-       } else
+       } else {
                end = 0;
+       }
 
        for (i = 0, curr = end;
             i < bsize;
@@ -370,10 +363,8 @@ static int nilfs_palloc_find_available_slot(struct inode *inode,
                        if (end > bsize)
                                end = bsize;
                        pos = nilfs_find_next_zero_bit(bitmap, end, curr);
-                       if ((pos < end) &&
-                           !nilfs_set_bit_atomic(
-                                   nilfs_mdt_bgl_lock(inode, group), pos,
-                                   bitmap))
+                       if (pos < end &&
+                           !nilfs_set_bit_atomic(lock, pos, bitmap))
                                return pos;
                }
        }
@@ -477,6 +468,7 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
        unsigned long group_offset, maxgroup_offset;
        unsigned long n, entries_per_group, groups_per_desc_block;
        unsigned long i, j;
+       spinlock_t *lock;
        int pos, ret;
 
        ngroups = nilfs_palloc_groups_count(inode);
@@ -501,8 +493,8 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
                n = nilfs_palloc_rest_groups_in_desc_block(inode, group,
                                                           maxgroup);
                for (j = 0; j < n; j++, desc++, group++) {
-                       if (nilfs_palloc_group_desc_nfrees(inode, group, desc)
-                           > 0) {
+                       lock = nilfs_mdt_bgl_lock(inode, group);
+                       if (nilfs_palloc_group_desc_nfrees(desc, lock) > 0) {
                                ret = nilfs_palloc_get_bitmap_block(
                                        inode, group, 1, &bitmap_bh);
                                if (ret < 0)
@@ -510,12 +502,12 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
                                bitmap_kaddr = kmap(bitmap_bh->b_page);
                                bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
                                pos = nilfs_palloc_find_available_slot(
-                                       inode, group, group_offset, bitmap,
-                                       entries_per_group);
+                                       bitmap, group_offset,
+                                       entries_per_group, lock);
                                if (pos >= 0) {
                                        /* found a free entry */
                                        nilfs_palloc_group_desc_add_entries(
-                                               inode, group, desc, -1);
+                                               desc, lock, -1);
                                        req->pr_entry_nr =
                                                entries_per_group * group + pos;
                                        kunmap(desc_bh->b_page);
@@ -573,6 +565,7 @@ void nilfs_palloc_commit_free_entry(struct inode *inode,
        unsigned long group, group_offset;
        unsigned char *bitmap;
        void *desc_kaddr, *bitmap_kaddr;
+       spinlock_t *lock;
 
        group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
        desc_kaddr = kmap(req->pr_desc_bh->b_page);
@@ -580,15 +573,15 @@ void nilfs_palloc_commit_free_entry(struct inode *inode,
                                                 req->pr_desc_bh, desc_kaddr);
        bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
        bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
+       lock = nilfs_mdt_bgl_lock(inode, group);
 
-       if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
-                                   group_offset, bitmap))
+       if (!nilfs_clear_bit_atomic(lock, group_offset, bitmap))
                nilfs_warning(inode->i_sb, __func__,
                              "entry number %llu already freed: ino=%lu\n",
                              (unsigned long long)req->pr_entry_nr,
                              (unsigned long)inode->i_ino);
        else
-               nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
+               nilfs_palloc_group_desc_add_entries(desc, lock, 1);
 
        kunmap(req->pr_bitmap_bh->b_page);
        kunmap(req->pr_desc_bh->b_page);
@@ -613,6 +606,7 @@ void nilfs_palloc_abort_alloc_entry(struct inode *inode,
        void *desc_kaddr, *bitmap_kaddr;
        unsigned char *bitmap;
        unsigned long group, group_offset;
+       spinlock_t *lock;
 
        group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
        desc_kaddr = kmap(req->pr_desc_bh->b_page);
@@ -620,14 +614,15 @@ void nilfs_palloc_abort_alloc_entry(struct inode *inode,
                                                 req->pr_desc_bh, desc_kaddr);
        bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
        bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
-       if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
-                                   group_offset, bitmap))
+       lock = nilfs_mdt_bgl_lock(inode, group);
+
+       if (!nilfs_clear_bit_atomic(lock, group_offset, bitmap))
                nilfs_warning(inode->i_sb, __func__,
                              "entry number %llu already freed: ino=%lu\n",
                              (unsigned long long)req->pr_entry_nr,
                              (unsigned long)inode->i_ino);
        else
-               nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
+               nilfs_palloc_group_desc_add_entries(desc, lock, 1);
 
        kunmap(req->pr_bitmap_bh->b_page);
        kunmap(req->pr_desc_bh->b_page);
@@ -712,6 +707,7 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
        unsigned char *bitmap;
        void *desc_kaddr, *bitmap_kaddr;
        unsigned long group, group_offset;
+       spinlock_t *lock;
        int i, j, n, ret;
 
        for (i = 0; i < nitems; i = j) {
@@ -730,14 +726,14 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
                        inode, group, desc_bh, desc_kaddr);
                bitmap_kaddr = kmap(bitmap_bh->b_page);
                bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
+               lock = nilfs_mdt_bgl_lock(inode, group);
                for (j = i, n = 0;
                     (j < nitems) && nilfs_palloc_group_is_in(inode, group,
                                                              entry_nrs[j]);
                     j++) {
                        nilfs_palloc_group(inode, entry_nrs[j], &group_offset);
-                       if (!nilfs_clear_bit_atomic(
-                                   nilfs_mdt_bgl_lock(inode, group),
-                                   group_offset, bitmap)) {
+                       if (!nilfs_clear_bit_atomic(lock, group_offset,
+                                                   bitmap)) {
                                nilfs_warning(inode->i_sb, __func__,
                                              "entry number %llu already freed: ino=%lu\n",
                                              (unsigned long long)entry_nrs[j],
@@ -746,7 +742,7 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
                                n++;
                        }
                }
-               nilfs_palloc_group_desc_add_entries(inode, group, desc, n);
+               nilfs_palloc_group_desc_add_entries(desc, lock, n);
 
                kunmap(bitmap_bh->b_page);
                kunmap(desc_bh->b_page);