UBUNTU: Ubuntu-2.6.38-12.51

[linux-flexiantxendom0-natty.git] / fs / buffer.c

diff --git a/fs/buffer.c b/fs/buffer.c
index ec21a92..2219a76 100644 (file)
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -905,7 +905,6 @@ try_again:
 
                bh->b_state = 0;
                atomic_set(&bh->b_count, 0);
-               bh->b_private = NULL;
                bh->b_size = size;
 
                /* Link the buffer to its page */
@@ -1271,12 +1270,10 @@ 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;
@@ -1284,7 +1281,8 @@ 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);
@@ -1299,7 +1297,7 @@ 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();
 
@@ -1314,23 +1312,22 @@ 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;
@@ -1834,9 +1831,11 @@ void page_zero_new_buffers(struct page *page, unsigned from, unsigned to)
 }
 EXPORT_SYMBOL(page_zero_new_buffers);
 
-int block_prepare_write(struct page *page, unsigned from, unsigned to,
+int __block_write_begin(struct page *page, loff_t pos, unsigned len,
                get_block_t *get_block)
 {
+       unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+       unsigned to = from + len;
        struct inode *inode = page->mapping->host;
        unsigned block_start, block_end;
        sector_t block;
@@ -1916,7 +1915,7 @@ int block_prepare_write(struct page *page, unsigned from, unsigned to,
        }
        return err;
 }
-EXPORT_SYMBOL(block_prepare_write);
+EXPORT_SYMBOL(__block_write_begin);
 
 static int __block_commit_write(struct inode *inode, struct page *page,
                unsigned from, unsigned to)
@@ -1953,15 +1952,6 @@ static int __block_commit_write(struct inode *inode, struct page *page,
        return 0;
 }
 
-int __block_write_begin(struct page *page, loff_t pos, unsigned len,
-               get_block_t *get_block)
-{
-       unsigned start = pos & (PAGE_CACHE_SIZE - 1);
-
-       return block_prepare_write(page, start, start + len, get_block);
-}
-EXPORT_SYMBOL(__block_write_begin);
-
 /*
  * block_write_begin takes care of the basic task of block allocation and
  * bringing partial write blocks uptodate first.
@@ -2379,7 +2369,7 @@ block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
        else
                end = PAGE_CACHE_SIZE;
 
-       ret = block_prepare_write(page, 0, end, get_block);
+       ret = __block_write_begin(page, 0, end, get_block);
        if (!ret)
                ret = block_commit_write(page, 0, end);
 
@@ -2466,11 +2456,10 @@ int nobh_write_begin(struct address_space *mapping,
        *fsdata = NULL;
 
        if (page_has_buffers(page)) {
-               unlock_page(page);
-               page_cache_release(page);
-               *pagep = NULL;
-               return block_write_begin(mapping, pos, len, flags, pagep,
-                                        get_block);
+               ret = __block_write_begin(page, pos, len, get_block);
+               if (unlikely(ret))
+                       goto out_release;
+               return ret;
        }
 
        if (PageMappedToDisk(page))
@@ -3212,22 +3201,23 @@ 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;
 }
@@ -3237,9 +3227,10 @@ 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);
 
@@ -3252,9 +3243,8 @@ 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,