7 files changed, 106 insertions, 96 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 983312cea245..8873ecd1578c 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -840,7 +840,7 @@ static bool over_bground_thresh(struct backing_dev_info *bdi)
             global_page_state(NR_UNSTABLE_NFS) > background_thresh)
                 return true;
 
-        if (bdi_stat(bdi, BDI_RECLAIMABLE) >
+        if (wb_stat(&bdi->wb, WB_RECLAIMABLE) >
                                 bdi_dirty_limit(bdi, background_thresh))
                 return true;
 
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 5ef05b5c4cff..8c5e2fa68835 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1445,9 +1445,9 @@ static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
 
         list_del(&req->writepages_entry);
         for (i = 0; i < req->num_pages; i++) {
-                dec_bdi_stat(bdi, BDI_WRITEBACK);
+                dec_wb_stat(&bdi->wb, WB_WRITEBACK);
                 dec_zone_page_state(req->pages[i], NR_WRITEBACK_TEMP);
-                bdi_writeout_inc(bdi);
+                wb_writeout_inc(&bdi->wb);
         }
         wake_up(&fi->page_waitq);
 }
@@ -1634,7 +1634,7 @@ static int fuse_writepage_locked(struct page *page)
         req->end = fuse_writepage_end;
         req->inode = inode;
 
-        inc_bdi_stat(inode_to_bdi(inode), BDI_WRITEBACK);
+        inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
         inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
 
         spin_lock(&fc->lock);
@@ -1749,9 +1749,9 @@ static bool fuse_writepage_in_flight(struct fuse_req *new_req,
                 copy_highpage(old_req->pages[0], page);
                 spin_unlock(&fc->lock);
 
-                dec_bdi_stat(bdi, BDI_WRITEBACK);
+                dec_wb_stat(&bdi->wb, WB_WRITEBACK);
                 dec_zone_page_state(page, NR_WRITEBACK_TEMP);
-                bdi_writeout_inc(bdi);
+                wb_writeout_inc(&bdi->wb);
                 fuse_writepage_free(fc, new_req);
                 fuse_request_free(new_req);
                 goto out;
@@ -1848,7 +1848,7 @@ static int fuse_writepages_fill(struct page *page,
         req->page_descs[req->num_pages].offset = 0;
         req->page_descs[req->num_pages].length = PAGE_SIZE;
 
-        inc_bdi_stat(inode_to_bdi(inode), BDI_WRITEBACK);
+        inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
         inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
 
         err = 0;
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 9e6475bc5ba2..7e3c4604bea8 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -607,7 +607,7 @@ void nfs_mark_page_unstable(struct page *page)
         struct inode *inode = page_file_mapping(page)->host;
 
         inc_zone_page_state(page, NR_UNSTABLE_NFS);
-        inc_bdi_stat(inode_to_bdi(inode), BDI_RECLAIMABLE);
+        inc_wb_stat(&inode_to_bdi(inode)->wb, WB_RECLAIMABLE);
          __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 }
 
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index d12a4be613a5..94c7ce01dfb1 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -853,7 +853,8 @@ static void
 nfs_clear_page_commit(struct page *page)
 {
         dec_zone_page_state(page, NR_UNSTABLE_NFS);
-        dec_bdi_stat(inode_to_bdi(page_file_mapping(page)->host), BDI_RECLAIMABLE);
+        dec_wb_stat(&inode_to_bdi(page_file_mapping(page)->host)->wb,
+                    WB_RECLAIMABLE);
 }
 
 /* Called holding inode (/cinfo) lock */
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index eb14f988a63e..fe7a907a4e16 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -36,15 +36,15 @@ enum wb_state {
 
 typedef int (congested_fn)(void *, int);
 
-enum bdi_stat_item {
-        BDI_RECLAIMABLE,
-        BDI_WRITEBACK,
-        BDI_DIRTIED,
-        BDI_WRITTEN,
-        NR_BDI_STAT_ITEMS
+enum wb_stat_item {
+        WB_RECLAIMABLE,
+        WB_WRITEBACK,
+        WB_DIRTIED,
+        WB_WRITTEN,
+        NR_WB_STAT_ITEMS
 };
 
-#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
+#define WB_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
 
 struct bdi_writeback {
         struct backing_dev_info *bdi;   /* our parent bdi */
@@ -58,6 +58,8 @@ struct bdi_writeback {
         struct list_head b_more_io;     /* parked for more writeback */
         struct list_head b_dirty_time;  /* time stamps are dirty */
         spinlock_t list_lock;           /* protects the b_* lists */
+
+        struct percpu_counter stat[NR_WB_STAT_ITEMS];
 };
 
 struct backing_dev_info {
@@ -69,8 +71,6 @@ struct backing_dev_info {
 
         char *name;
 
-        struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];
-
         unsigned long bw_time_stamp;    /* last time write bw is updated */
         unsigned long dirtied_stamp;
         unsigned long written_stamp;    /* pages written at bw_time_stamp */
@@ -137,78 +137,74 @@ static inline int wb_has_dirty_io(struct bdi_writeback *wb)
                !list_empty(&wb->b_more_io);
 }
 
-static inline void __add_bdi_stat(struct backing_dev_info *bdi,
-                enum bdi_stat_item item, s64 amount)
+static inline void __add_wb_stat(struct bdi_writeback *wb,
+                                 enum wb_stat_item item, s64 amount)
 {
-        __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
+        __percpu_counter_add(&wb->stat[item], amount, WB_STAT_BATCH);
 }
 
-static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
-                enum bdi_stat_item item)
+static inline void __inc_wb_stat(struct bdi_writeback *wb,
+                                 enum wb_stat_item item)
 {
-        __add_bdi_stat(bdi, item, 1);
+        __add_wb_stat(wb, item, 1);
 }
 
-static inline void inc_bdi_stat(struct backing_dev_info *bdi,
-                enum bdi_stat_item item)
+static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
 {
         unsigned long flags;
 
         local_irq_save(flags);
-        __inc_bdi_stat(bdi, item);
+        __inc_wb_stat(wb, item);
         local_irq_restore(flags);
 }
 
-static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
-                enum bdi_stat_item item)
+static inline void __dec_wb_stat(struct bdi_writeback *wb,
+                                 enum wb_stat_item item)
 {
-        __add_bdi_stat(bdi, item, -1);
+        __add_wb_stat(wb, item, -1);
 }
 
-static inline void dec_bdi_stat(struct backing_dev_info *bdi,
-                enum bdi_stat_item item)
+static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
 {
         unsigned long flags;
 
         local_irq_save(flags);
-        __dec_bdi_stat(bdi, item);
+        __dec_wb_stat(wb, item);
         local_irq_restore(flags);
 }
 
-static inline s64 bdi_stat(struct backing_dev_info *bdi,
-                enum bdi_stat_item item)
+static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
 {
-        return percpu_counter_read_positive(&bdi->bdi_stat[item]);
+        return percpu_counter_read_positive(&wb->stat[item]);
 }
 
-static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
-                enum bdi_stat_item item)
+static inline s64 __wb_stat_sum(struct bdi_writeback *wb,
+                                enum wb_stat_item item)
 {
-        return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
+        return percpu_counter_sum_positive(&wb->stat[item]);
 }
 
-static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
-                enum bdi_stat_item item)
+static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item)
 {
         s64 sum;
         unsigned long flags;
 
         local_irq_save(flags);
-        sum = __bdi_stat_sum(bdi, item);
+        sum = __wb_stat_sum(wb, item);
         local_irq_restore(flags);
 
         return sum;
 }
 
-extern void bdi_writeout_inc(struct backing_dev_info *bdi);
+extern void wb_writeout_inc(struct bdi_writeback *wb);
 
 /*
  * maximal error of a stat counter.
  */
-static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
+static inline unsigned long wb_stat_error(struct bdi_writeback *wb)
 {
 #ifdef CONFIG_SMP
-        return nr_cpu_ids * BDI_STAT_BATCH;
+        return nr_cpu_ids * WB_STAT_BATCH;
 #else
         return 1;
 #endif
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index b23cf0ea5912..7b1d1917b658 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -84,13 +84,13 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
                    "b_dirty_time:       %10lu\n"
                    "bdi_list:           %10u\n"
                    "state:              %10lx\n",
-                   (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)),
-                   (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)),
+                   (unsigned long) K(wb_stat(wb, WB_WRITEBACK)),
+                   (unsigned long) K(wb_stat(wb, WB_RECLAIMABLE)),
                    K(bdi_thresh),
                    K(dirty_thresh),
                    K(background_thresh),
-                   (unsigned long) K(bdi_stat(bdi, BDI_DIRTIED)),
-                   (unsigned long) K(bdi_stat(bdi, BDI_WRITTEN)),
+                   (unsigned long) K(wb_stat(wb, WB_DIRTIED)),
+                   (unsigned long) K(wb_stat(wb, WB_WRITTEN)),
                    (unsigned long) K(bdi->write_bandwidth),
                    nr_dirty,
                    nr_io,
@@ -376,8 +376,10 @@ void bdi_unregister(struct backing_dev_info *bdi)
 }
 EXPORT_SYMBOL(bdi_unregister);
 
-static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
+static int bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
 {
+        int i, err;
+
         memset(wb, 0, sizeof(*wb));
 
         wb->bdi = bdi;
@@ -388,6 +390,27 @@ static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
         INIT_LIST_HEAD(&wb->b_dirty_time);
         spin_lock_init(&wb->list_lock);
         INIT_DELAYED_WORK(&wb->dwork, bdi_writeback_workfn);
+
+        for (i = 0; i < NR_WB_STAT_ITEMS; i++) {
+                err = percpu_counter_init(&wb->stat[i], 0, GFP_KERNEL);
+                if (err) {
+                        while (--i)
+                                percpu_counter_destroy(&wb->stat[i]);
+                        return err;
+                }
+        }
+
+        return 0;
+}
+
+static void bdi_wb_exit(struct bdi_writeback *wb)
+{
+        int i;
+
+        WARN_ON(delayed_work_pending(&wb->dwork));
+
+        for (i = 0; i < NR_WB_STAT_ITEMS; i++)
+                percpu_counter_destroy(&wb->stat[i]);
 }
 
 /*
@@ -397,7 +420,7 @@ static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
 
 int bdi_init(struct backing_dev_info *bdi)
 {
-        int i, err;
+        int err;
 
         bdi->dev = NULL;
 
@@ -408,13 +431,9 @@ int bdi_init(struct backing_dev_info *bdi)
         INIT_LIST_HEAD(&bdi->bdi_list);
         INIT_LIST_HEAD(&bdi->work_list);
 
-        bdi_wb_init(&bdi->wb, bdi);
-
-        for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
-                err = percpu_counter_init(&bdi->bdi_stat[i], 0, GFP_KERNEL);
-                if (err)
-                        goto err;
-        }
+        err = bdi_wb_init(&bdi->wb, bdi);
+        if (err)
+                return err;
 
         bdi->dirty_exceeded = 0;
 
@@ -427,25 +446,20 @@ int bdi_init(struct backing_dev_info *bdi)
         bdi->avg_write_bandwidth = INIT_BW;
 
         err = fprop_local_init_percpu(&bdi->completions, GFP_KERNEL);
-
         if (err) {
-err:
-                while (i--)
-                        percpu_counter_destroy(&bdi->bdi_stat[i]);
+                bdi_wb_exit(&bdi->wb);
+                return err;
         }
 
-        return err;
+        return 0;
 }
 EXPORT_SYMBOL(bdi_init);
 
 void bdi_destroy(struct backing_dev_info *bdi)
 {
-        int i;
-
         bdi_wb_shutdown(bdi);
 
         WARN_ON(!list_empty(&bdi->work_list));
-        WARN_ON(delayed_work_pending(&bdi->wb.dwork));
 
         if (bdi->dev) {
                 bdi_debug_unregister(bdi);
@@ -453,8 +467,8 @@ void bdi_destroy(struct backing_dev_info *bdi)
                 bdi->dev = NULL;
         }
 
-        for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
-                percpu_counter_destroy(&bdi->bdi_stat[i]);
+        bdi_wb_exit(&bdi->wb);
+
         fprop_local_destroy_percpu(&bdi->completions);
 }
 EXPORT_SYMBOL(bdi_destroy);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index bdeecad00489..dc673a035413 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -396,11 +396,11 @@ static unsigned long wp_next_time(unsigned long cur_time)
  * Increment the BDI's writeout completion count and the global writeout
  * completion count. Called from test_clear_page_writeback().
  */
-static inline void __bdi_writeout_inc(struct backing_dev_info *bdi)
+static inline void __wb_writeout_inc(struct bdi_writeback *wb)
 {
-        __inc_bdi_stat(bdi, BDI_WRITTEN);
-        __fprop_inc_percpu_max(&writeout_completions, &bdi->completions,
-                               bdi->max_prop_frac);
+        __inc_wb_stat(wb, WB_WRITTEN);
+        __fprop_inc_percpu_max(&writeout_completions, &wb->bdi->completions,
+                               wb->bdi->max_prop_frac);
         /* First event after period switching was turned off? */
         if (!unlikely(writeout_period_time)) {
                 /*
@@ -414,15 +414,15 @@ static inline void __bdi_writeout_inc(struct backing_dev_info *bdi)
         }
 }
 
-void bdi_writeout_inc(struct backing_dev_info *bdi)
+void wb_writeout_inc(struct bdi_writeback *wb)
 {
         unsigned long flags;
 
         local_irq_save(flags);
-        __bdi_writeout_inc(bdi);
+        __wb_writeout_inc(wb);
         local_irq_restore(flags);
 }
-EXPORT_SYMBOL_GPL(bdi_writeout_inc);
+EXPORT_SYMBOL_GPL(wb_writeout_inc);
 
 /*
  * Obtain an accurate fraction of the BDI's portion.
@@ -1130,8 +1130,8 @@ void __bdi_update_bandwidth(struct backing_dev_info *bdi,
         if (elapsed < BANDWIDTH_INTERVAL)
                 return;
 
-        dirtied = percpu_counter_read(&bdi->bdi_stat[BDI_DIRTIED]);
-        written = percpu_counter_read(&bdi->bdi_stat[BDI_WRITTEN]);
+        dirtied = percpu_counter_read(&bdi->wb.stat[WB_DIRTIED]);
+        written = percpu_counter_read(&bdi->wb.stat[WB_WRITTEN]);
 
         /*
          * Skip quiet periods when disk bandwidth is under-utilized.
@@ -1288,7 +1288,8 @@ static inline void bdi_dirty_limits(struct backing_dev_info *bdi,
                                     unsigned long *bdi_thresh,
                                     unsigned long *bdi_bg_thresh)
 {
-        unsigned long bdi_reclaimable;
+        struct bdi_writeback *wb = &bdi->wb;
+        unsigned long wb_reclaimable;
 
         /*
          * bdi_thresh is not treated as some limiting factor as
@@ -1320,14 +1321,12 @@ static inline void bdi_dirty_limits(struct backing_dev_info *bdi,
          * actually dirty; with m+n sitting in the percpu
          * deltas.
          */
-        if (*bdi_thresh < 2 * bdi_stat_error(bdi)) {
-                bdi_reclaimable = bdi_stat_sum(bdi, BDI_RECLAIMABLE);
-                *bdi_dirty = bdi_reclaimable +
-                        bdi_stat_sum(bdi, BDI_WRITEBACK);
+        if (*bdi_thresh < 2 * wb_stat_error(wb)) {
+                wb_reclaimable = wb_stat_sum(wb, WB_RECLAIMABLE);
+                *bdi_dirty = wb_reclaimable + wb_stat_sum(wb, WB_WRITEBACK);
         } else {
-                bdi_reclaimable = bdi_stat(bdi, BDI_RECLAIMABLE);
-                *bdi_dirty = bdi_reclaimable +
-                        bdi_stat(bdi, BDI_WRITEBACK);
+                wb_reclaimable = wb_stat(wb, WB_RECLAIMABLE);
+                *bdi_dirty = wb_reclaimable + wb_stat(wb, WB_WRITEBACK);
         }
 }
 
@@ -1514,9 +1513,9 @@ pause:
                  * In theory 1 page is enough to keep the comsumer-producer
                  * pipe going: the flusher cleans 1 page => the task dirties 1
                  * more page. However bdi_dirty has accounting errors.  So use
-                 * the larger and more IO friendly bdi_stat_error.
+                 * the larger and more IO friendly wb_stat_error.
                  */
-                if (bdi_dirty <= bdi_stat_error(bdi))
+                if (bdi_dirty <= wb_stat_error(&bdi->wb))
                         break;
 
                 if (fatal_signal_pending(current))
@@ -2106,8 +2105,8 @@ void account_page_dirtied(struct page *page, struct address_space *mapping,
                 mem_cgroup_inc_page_stat(memcg, MEM_CGROUP_STAT_DIRTY);
                 __inc_zone_page_state(page, NR_FILE_DIRTY);
                 __inc_zone_page_state(page, NR_DIRTIED);
-                __inc_bdi_stat(bdi, BDI_RECLAIMABLE);
-                __inc_bdi_stat(bdi, BDI_DIRTIED);
+                __inc_wb_stat(&bdi->wb, WB_RECLAIMABLE);
+                __inc_wb_stat(&bdi->wb, WB_DIRTIED);
                 task_io_account_write(PAGE_CACHE_SIZE);
                 current->nr_dirtied++;
                 this_cpu_inc(bdp_ratelimits);
@@ -2126,7 +2125,7 @@ void account_page_cleaned(struct page *page, struct address_space *mapping,
         if (mapping_cap_account_dirty(mapping)) {
                 mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_DIRTY);
                 dec_zone_page_state(page, NR_FILE_DIRTY);
-                dec_bdi_stat(inode_to_bdi(mapping->host), BDI_RECLAIMABLE);
+                dec_wb_stat(&inode_to_bdi(mapping->host)->wb, WB_RECLAIMABLE);
                 task_io_account_cancelled_write(PAGE_CACHE_SIZE);
         }
 }
@@ -2190,7 +2189,7 @@ void account_page_redirty(struct page *page)
         if (mapping && mapping_cap_account_dirty(mapping)) {
                 current->nr_dirtied--;
                 dec_zone_page_state(page, NR_DIRTIED);
-                dec_bdi_stat(inode_to_bdi(mapping->host), BDI_DIRTIED);
+                dec_wb_stat(&inode_to_bdi(mapping->host)->wb, WB_DIRTIED);
         }
 }
 EXPORT_SYMBOL(account_page_redirty);
@@ -2369,8 +2368,8 @@ int clear_page_dirty_for_io(struct page *page)
                 if (TestClearPageDirty(page)) {
                         mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_DIRTY);
                         dec_zone_page_state(page, NR_FILE_DIRTY);
-                        dec_bdi_stat(inode_to_bdi(mapping->host),
-                                        BDI_RECLAIMABLE);
+                        dec_wb_stat(&inode_to_bdi(mapping->host)->wb,
+                                    WB_RECLAIMABLE);
                         ret = 1;
                 }
                 mem_cgroup_end_page_stat(memcg);
@@ -2398,8 +2397,8 @@ int test_clear_page_writeback(struct page *page)
                                                 page_index(page),
                                                 PAGECACHE_TAG_WRITEBACK);
                         if (bdi_cap_account_writeback(bdi)) {
-                                __dec_bdi_stat(bdi, BDI_WRITEBACK);
-                                __bdi_writeout_inc(bdi);
+                                __dec_wb_stat(&bdi->wb, WB_WRITEBACK);
+                                __wb_writeout_inc(&bdi->wb);
                         }
                 }
                 spin_unlock_irqrestore(&mapping->tree_lock, flags);
@@ -2433,7 +2432,7 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
                                                 page_index(page),
                                                 PAGECACHE_TAG_WRITEBACK);
                         if (bdi_cap_account_writeback(bdi))
-                                __inc_bdi_stat(bdi, BDI_WRITEBACK);
+                                __inc_wb_stat(&bdi->wb, WB_WRITEBACK);
                 }
                 if (!PageDirty(page))
                         radix_tree_tag_clear(&mapping->page_tree,