1 files changed, 33 insertions, 57 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 5930e382959b..a08bb8e61c6f 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -54,23 +54,15 @@ init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private)
 }
 EXPORT_SYMBOL(init_buffer);
 
-static int sync_buffer(void *word)
+static int sleep_on_buffer(void *word)
 {
-        struct block_device *bd;
-        struct buffer_head *bh
-                = container_of(word, struct buffer_head, b_state);
-
-        smp_mb();
-        bd = bh->b_bdev;
-        if (bd)
-                blk_run_address_space(bd->bd_inode->i_mapping);
         io_schedule();
         return 0;
 }
 
 void __lock_buffer(struct buffer_head *bh)
 {
-        wait_on_bit_lock(&bh->b_state, BH_Lock, sync_buffer,
+        wait_on_bit_lock(&bh->b_state, BH_Lock, sleep_on_buffer,
                                                         TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL(__lock_buffer);
@@ -90,7 +82,7 @@ EXPORT_SYMBOL(unlock_buffer);
  */
 void __wait_on_buffer(struct buffer_head * bh)
 {
-        wait_on_bit(&bh->b_state, BH_Lock, sync_buffer, TASK_UNINTERRUPTIBLE);
+        wait_on_bit(&bh->b_state, BH_Lock, sleep_on_buffer, TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL(__wait_on_buffer);
 
@@ -749,10 +741,12 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
 {
         struct buffer_head *bh;
         struct list_head tmp;
-        struct address_space *mapping, *prev_mapping = NULL;
+        struct address_space *mapping;
         int err = 0, err2;
+        struct blk_plug plug;
 
         INIT_LIST_HEAD(&tmp);
+        blk_start_plug(&plug);
 
         spin_lock(lock);
         while (!list_empty(list)) {
@@ -775,7 +769,7 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
                                  * still in flight on potentially older
                                  * contents.
                                  */
-                                write_dirty_buffer(bh, WRITE_SYNC_PLUG);
+                                write_dirty_buffer(bh, WRITE_SYNC);
 
                                 /*
                                  * Kick off IO for the previous mapping. Note
@@ -783,16 +777,16 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
                                  * wait_on_buffer() will do that for us
                                  * through sync_buffer().
                                  */
-                                if (prev_mapping && prev_mapping != mapping)
-                                        blk_run_address_space(prev_mapping);
-                                prev_mapping = mapping;
-
                                 brelse(bh);
                                 spin_lock(lock);
                         }
                 }
         }
 
+        spin_unlock(lock);
+        blk_finish_plug(&plug);
+        spin_lock(lock);
+
         while (!list_empty(&tmp)) {
                 bh = BH_ENTRY(tmp.prev);
                 get_bh(bh);
@@ -1144,7 +1138,7 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size)
  * inode list.
  *
  * mark_buffer_dirty() is atomic.  It takes bh->b_page->mapping->private_lock,
- * mapping->tree_lock and the global inode_lock.
+ * mapping->tree_lock and mapping->host->i_lock.
  */
 void mark_buffer_dirty(struct buffer_head *bh)
 {
@@ -1270,12 +1264,10 @@ static inline void check_irqs_on(void)
 static void bh_lru_install(struct buffer_head *bh)
 {
         struct buffer_head *evictee = NULL;
-        struct bh_lru *lru;
 
         check_irqs_on();
         bh_lru_lock();
-        lru = &__get_cpu_var(bh_lrus);
-        if (lru->bhs[0] != bh) {
+        if (__this_cpu_read(bh_lrus.bhs[0]) != bh) {
                 struct buffer_head *bhs[BH_LRU_SIZE];
                 int in;
                 int out = 0;
@@ -1283,7 +1275,8 @@ static void bh_lru_install(struct buffer_head *bh)
                 get_bh(bh);
                 bhs[out++] = bh;
                 for (in = 0; in < BH_LRU_SIZE; in++) {
-                        struct buffer_head *bh2 = lru->bhs[in];
+                        struct buffer_head *bh2 =
+                                __this_cpu_read(bh_lrus.bhs[in]);
 
                         if (bh2 == bh) {
                                 __brelse(bh2);
@@ -1298,7 +1291,7 @@ static void bh_lru_install(struct buffer_head *bh)
                 }
                 while (out < BH_LRU_SIZE)
                         bhs[out++] = NULL;
-                memcpy(lru->bhs, bhs, sizeof(bhs));
+                memcpy(__this_cpu_ptr(&bh_lrus.bhs), bhs, sizeof(bhs));
         }
         bh_lru_unlock();
 
@@ -1313,23 +1306,22 @@ static struct buffer_head *
 lookup_bh_lru(struct block_device *bdev, sector_t block, unsigned size)
 {
         struct buffer_head *ret = NULL;
-        struct bh_lru *lru;
         unsigned int i;
 
         check_irqs_on();
         bh_lru_lock();
-        lru = &__get_cpu_var(bh_lrus);
         for (i = 0; i < BH_LRU_SIZE; i++) {
-                struct buffer_head *bh = lru->bhs[i];
+                struct buffer_head *bh = __this_cpu_read(bh_lrus.bhs[i]);
 
                 if (bh && bh->b_bdev == bdev &&
                                 bh->b_blocknr == block && bh->b_size == size) {
                         if (i) {
                                 while (i) {
-                                        lru->bhs[i] = lru->bhs[i - 1];
+                                        __this_cpu_write(bh_lrus.bhs[i],
+                                                __this_cpu_read(bh_lrus.bhs[i - 1]));
                                         i--;
                                 }
-                                lru->bhs[0] = bh;
+                                __this_cpu_write(bh_lrus.bhs[0], bh);
                         }
                         get_bh(bh);
                         ret = bh;
@@ -1616,14 +1608,8 @@ EXPORT_SYMBOL(unmap_underlying_metadata);
  * prevents this contention from occurring.
  *
  * If block_write_full_page() is called with wbc->sync_mode ==
- * WB_SYNC_ALL, the writes are posted using WRITE_SYNC_PLUG; this
- * causes the writes to be flagged as synchronous writes, but the
- * block device queue will NOT be unplugged, since usually many pages
- * will be pushed to the out before the higher-level caller actually
- * waits for the writes to be completed.  The various wait functions,
- * such as wait_on_writeback_range() will ultimately call sync_page()
- * which will ultimately call blk_run_backing_dev(), which will end up
- * unplugging the device queue.
+ * WB_SYNC_ALL, the writes are posted using WRITE_SYNC; this
+ * causes the writes to be flagged as synchronous writes.
  */
 static int __block_write_full_page(struct inode *inode, struct page *page,
                         get_block_t *get_block, struct writeback_control *wbc,
@@ -1636,7 +1622,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
         const unsigned blocksize = 1 << inode->i_blkbits;
         int nr_underway = 0;
         int write_op = (wbc->sync_mode == WB_SYNC_ALL ?
-                        WRITE_SYNC_PLUG : WRITE);
+                        WRITE_SYNC : WRITE);
 
         BUG_ON(!PageLocked(page));
 
@@ -3140,17 +3126,6 @@ out:
 }
 EXPORT_SYMBOL(try_to_free_buffers);
 
-void block_sync_page(struct page *page)
-{
-        struct address_space *mapping;
-
-        smp_mb();
-        mapping = page_mapping(page);
-        if (mapping)
-                blk_run_backing_dev(mapping->backing_dev_info, page);
-}
-EXPORT_SYMBOL(block_sync_page);
-
 /*
  * There are no bdflush tunables left.  But distributions are
  * still running obsolete flush daemons, so we terminate them here.
@@ -3203,22 +3178,23 @@ static void recalc_bh_state(void)
         int i;
         int tot = 0;
 
-        if (__get_cpu_var(bh_accounting).ratelimit++ < 4096)
+        if (__this_cpu_inc_return(bh_accounting.ratelimit) - 1 < 4096)
                 return;
-        __get_cpu_var(bh_accounting).ratelimit = 0;
+        __this_cpu_write(bh_accounting.ratelimit, 0);
         for_each_online_cpu(i)
                 tot += per_cpu(bh_accounting, i).nr;
         buffer_heads_over_limit = (tot > max_buffer_heads);
 }
-        
+
 struct buffer_head *alloc_buffer_head(gfp_t gfp_flags)
 {
         struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, gfp_flags);
         if (ret) {
                 INIT_LIST_HEAD(&ret->b_assoc_buffers);
-                get_cpu_var(bh_accounting).nr++;
+                preempt_disable();
+                __this_cpu_inc(bh_accounting.nr);
                 recalc_bh_state();
-                put_cpu_var(bh_accounting);
+                preempt_enable();
         }
         return ret;
 }
@@ -3228,9 +3204,10 @@ void free_buffer_head(struct buffer_head *bh)
 {
         BUG_ON(!list_empty(&bh->b_assoc_buffers));
         kmem_cache_free(bh_cachep, bh);
-        get_cpu_var(bh_accounting).nr--;
+        preempt_disable();
+        __this_cpu_dec(bh_accounting.nr);
         recalc_bh_state();
-        put_cpu_var(bh_accounting);
+        preempt_enable();
 }
 EXPORT_SYMBOL(free_buffer_head);
 
@@ -3243,9 +3220,8 @@ static void buffer_exit_cpu(int cpu)
                 brelse(b->bhs[i]);
                 b->bhs[i] = NULL;
         }
-        get_cpu_var(bh_accounting).nr += per_cpu(bh_accounting, cpu).nr;
+        this_cpu_add(bh_accounting.nr, per_cpu(bh_accounting, cpu).nr);
         per_cpu(bh_accounting, cpu).nr = 0;
-        put_cpu_var(bh_accounting);
 }
 
 static int buffer_cpu_notify(struct notifier_block *self,