bdi: invert BDI_CAP_NO_ACCT_WB

Replace BDI_CAP_NO_ACCT_WB with a positive BDI_CAP_WRITEBACK_ACCT to
make the checks more obvious.  Also remove the pointless
bdi_cap_account_writeback wrapper that just obsfucates the check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 17b0067..5813292 100644 (file)
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1050,7 +1050,8 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
                return err;
 
        /* fuse does it's own writeback accounting */
-       sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
+       sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
+       sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
 
        /*
         * For a single fuse filesystem use max 1% of dirty +

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 5da4ea3..b217344 100644 (file)
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -120,17 +120,17 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
  *
  * BDI_CAP_NO_ACCT_DIRTY:  Dirty pages shouldn't contribute to accounting
  * BDI_CAP_NO_WRITEBACK:   Don't write pages back
- * BDI_CAP_NO_ACCT_WB:     Don't automatically account writeback pages
+ * BDI_CAP_WRITEBACK_ACCT: Automatically account writeback pages
  * BDI_CAP_STRICTLIMIT:    Keep number of dirty pages below bdi threshold.
  */
 #define BDI_CAP_NO_ACCT_DIRTY  0x00000001
 #define BDI_CAP_NO_WRITEBACK   0x00000002
-#define BDI_CAP_NO_ACCT_WB     0x00000004
+#define BDI_CAP_WRITEBACK_ACCT 0x00000004
 #define BDI_CAP_STRICTLIMIT    0x00000010
 #define BDI_CAP_CGROUP_WRITEBACK 0x00000020
 
 #define BDI_CAP_NO_ACCT_AND_WRITEBACK \
-       (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
+       (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY)
 
 extern struct backing_dev_info noop_backing_dev_info;
 
@@ -179,13 +179,6 @@ static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
        return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
 }
 
-static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
-{
-       /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
-       return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB |
-                                     BDI_CAP_NO_WRITEBACK));
-}
-
 static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
 {
        return bdi_cap_writeback_dirty(inode_to_bdi(mapping->host));

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 8e3802b..df18f00 100644 (file)
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -745,6 +745,7 @@ struct backing_dev_info *bdi_alloc(int node_id)
                kfree(bdi);
                return NULL;
        }
+       bdi->capabilities = BDI_CAP_WRITEBACK_ACCT;
        bdi->ra_pages = VM_READAHEAD_PAGES;
        bdi->io_pages = VM_READAHEAD_PAGES;
        return bdi;

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index e9c3652..0139f96 100644 (file)
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2738,7 +2738,7 @@ int test_clear_page_writeback(struct page *page)
                if (ret) {
                        __xa_clear_mark(&mapping->i_pages, page_index(page),
                                                PAGECACHE_TAG_WRITEBACK);
-                       if (bdi_cap_account_writeback(bdi)) {
+                       if (bdi->capabilities & BDI_CAP_WRITEBACK_ACCT) {
                                struct bdi_writeback *wb = inode_to_wb(inode);
 
                                dec_wb_stat(wb, WB_WRITEBACK);
@@ -2791,7 +2791,7 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
                                                   PAGECACHE_TAG_WRITEBACK);
 
                        xas_set_mark(&xas, PAGECACHE_TAG_WRITEBACK);
-                       if (bdi_cap_account_writeback(bdi))
+                       if (bdi->capabilities & BDI_CAP_WRITEBACK_ACCT)
                                inc_wb_stat(inode_to_wb(inode), WB_WRITEBACK);
 
                        /*