Merge branch 'for-3.20/bdi' of git://git.kernel.dk/linux-block

Pull backing device changes from Jens Axboe:
 "This contains a cleanup of how the backing device is handled, in
  preparation for a rework of the life time rules.  In this part, the
  most important change is to split the unrelated nommu mmap flags from
  it, but also removing a backing_dev_info pointer from the
  address_space (and inode), and a cleanup of other various minor bits.

  Christoph did all the work here, I just fixed an oops with pages that
  have a swap backing.  Arnd fixed a missing export, and Oleg killed the
  lustre backing_dev_info from staging.  Last patch was from Al,
  unexporting parts that are now no longer needed outside"

* 'for-3.20/bdi' of git://git.kernel.dk/linux-block:
  Make super_blocks and sb_lock static
  mtd: export new mtd_mmap_capabilities
  fs: make inode_to_bdi() handle NULL inode
  staging/lustre/llite: get rid of backing_dev_info
  fs: remove default_backing_dev_info
  fs: don't reassign dirty inodes to default_backing_dev_info
  nfs: don't call bdi_unregister
  ceph: remove call to bdi_unregister
  fs: remove mapping->backing_dev_info
  fs: export inode_to_bdi and use it in favor of mapping->backing_dev_info
  nilfs2: set up s_bdi like the generic mount_bdev code
  block_dev: get bdev inode bdi directly from the block device
  block_dev: only write bdev inode on close
  fs: introduce f_op->mmap_capabilities for nommu mmap support
  fs: kill BDI_CAP_SWAP_BACKED
  fs: deduplicate noop_backing_dev_info

5 files changed, 39 insertions, 58 deletions

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 5da6012b7a14..d94077fea1f8 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -106,6 +106,8 @@ struct backing_dev_info {
 #endif
 };
 
+struct backing_dev_info *inode_to_bdi(struct inode *inode);
+
 int __must_check bdi_init(struct backing_dev_info *bdi);
 void bdi_destroy(struct backing_dev_info *bdi);
 
@@ -114,7 +116,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
                 const char *fmt, ...);
 int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
 void bdi_unregister(struct backing_dev_info *bdi);
-int __must_check bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int);
+int __must_check bdi_setup_and_register(struct backing_dev_info *, char *);
 void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
                         enum wb_reason reason);
 void bdi_start_background_writeback(struct backing_dev_info *bdi);
@@ -228,46 +230,17 @@ 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
- *
- * These flags let !MMU mmap() govern direct device mapping vs immediate
- * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
- *
- * BDI_CAP_MAP_COPY:       Copy can be mapped (MAP_PRIVATE)
- * BDI_CAP_MAP_DIRECT:     Can be mapped directly (MAP_SHARED)
- * BDI_CAP_READ_MAP:       Can be mapped for reading
- * BDI_CAP_WRITE_MAP:      Can be mapped for writing
- * BDI_CAP_EXEC_MAP:       Can be mapped for execution
- *
- * BDI_CAP_SWAP_BACKED:    Count shmem/tmpfs objects as swap-backed.
- *
  * 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_MAP_COPY        0x00000004
-#define BDI_CAP_MAP_DIRECT      0x00000008
-#define BDI_CAP_READ_MAP        0x00000010
-#define BDI_CAP_WRITE_MAP       0x00000020
-#define BDI_CAP_EXEC_MAP        0x00000040
-#define BDI_CAP_NO_ACCT_WB      0x00000080
-#define BDI_CAP_SWAP_BACKED     0x00000100
-#define BDI_CAP_STABLE_WRITES   0x00000200
-#define BDI_CAP_STRICTLIMIT     0x00000400
-
-#define BDI_CAP_VMFLAGS \
-        (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)
+#define BDI_CAP_NO_ACCT_WB      0x00000004
+#define BDI_CAP_STABLE_WRITES   0x00000008
+#define BDI_CAP_STRICTLIMIT     0x00000010
 
 #define BDI_CAP_NO_ACCT_AND_WRITEBACK \
         (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
 
-#if defined(VM_MAYREAD) && \
-        (BDI_CAP_READ_MAP != VM_MAYREAD || \
-         BDI_CAP_WRITE_MAP != VM_MAYWRITE || \
-         BDI_CAP_EXEC_MAP != VM_MAYEXEC)
-#error please change backing_dev_info::capabilities flags
-#endif
-
-extern struct backing_dev_info default_backing_dev_info;
 extern struct backing_dev_info noop_backing_dev_info;
 
 int writeback_in_progress(struct backing_dev_info *bdi);
@@ -329,24 +302,14 @@ static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
                                       BDI_CAP_NO_WRITEBACK));
 }
 
-static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
-{
-        return bdi->capabilities & BDI_CAP_SWAP_BACKED;
-}
-
 static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
 {
-        return bdi_cap_writeback_dirty(mapping->backing_dev_info);
+        return bdi_cap_writeback_dirty(inode_to_bdi(mapping->host));
 }
 
 static inline bool mapping_cap_account_dirty(struct address_space *mapping)
 {
-        return bdi_cap_account_dirty(mapping->backing_dev_info);
-}
-
-static inline bool mapping_cap_swap_backed(struct address_space *mapping)
-{
-        return bdi_cap_swap_backed(mapping->backing_dev_info);
+        return bdi_cap_account_dirty(inode_to_bdi(mapping->host));
 }
 
 static inline int bdi_sched_wait(void *word)
diff --git a/include/linux/cdev.h b/include/linux/cdev.h
index fb4591977b03..f8763615a5f2 100644
--- a/include/linux/cdev.h
+++ b/include/linux/cdev.h
@@ -30,6 +30,4 @@ void cdev_del(struct cdev *);
 
 void cd_forget(struct inode *);
 
-extern struct backing_dev_info directly_mappable_cdev_bdi;
-
 #endif
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cdcb1e9d9613..ec0f1dc66b9b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -34,6 +34,7 @@
 #include <asm/byteorder.h>
 #include <uapi/linux/fs.h>
 
+struct backing_dev_info;
 struct export_operations;
 struct hd_geometry;
 struct iovec;
@@ -394,7 +395,6 @@ int pagecache_write_end(struct file *, struct address_space *mapping,
                                 loff_t pos, unsigned len, unsigned copied,
                                 struct page *page, void *fsdata);
 
-struct backing_dev_info;
 struct address_space {
         struct inode            *host;          /* owner: inode, block_device */
         struct radix_tree_root  page_tree;      /* radix tree of all pages */
@@ -408,7 +408,6 @@ struct address_space {
         pgoff_t                 writeback_index;/* writeback starts here */
         const struct address_space_operations *a_ops;   /* methods */
         unsigned long           flags;          /* error bits/gfp mask */
-        struct backing_dev_info *backing_dev_info; /* device readahead, etc */
         spinlock_t              private_lock;   /* for use by the address_space */
         struct list_head        private_list;   /* ditto */
         void                    *private_data;  /* ditto */
@@ -1201,8 +1200,6 @@ struct mm_struct;
 #define UMOUNT_NOFOLLOW 0x00000008      /* Don't follow symlink on umount */
 #define UMOUNT_UNUSED   0x80000000      /* Flag guaranteed to be unused */
 
-extern struct list_head super_blocks;
-extern spinlock_t sb_lock;
 
 /* Possible states of 'frozen' field */
 enum {
@@ -1519,6 +1516,26 @@ struct block_device_operations;
 #define HAVE_COMPAT_IOCTL 1
 #define HAVE_UNLOCKED_IOCTL 1
 
+/*
+ * These flags let !MMU mmap() govern direct device mapping vs immediate
+ * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
+ *
+ * NOMMU_MAP_COPY:      Copy can be mapped (MAP_PRIVATE)
+ * NOMMU_MAP_DIRECT:    Can be mapped directly (MAP_SHARED)
+ * NOMMU_MAP_READ:      Can be mapped for reading
+ * NOMMU_MAP_WRITE:     Can be mapped for writing
+ * NOMMU_MAP_EXEC:      Can be mapped for execution
+ */
+#define NOMMU_MAP_COPY          0x00000001
+#define NOMMU_MAP_DIRECT        0x00000008
+#define NOMMU_MAP_READ          VM_MAYREAD
+#define NOMMU_MAP_WRITE         VM_MAYWRITE
+#define NOMMU_MAP_EXEC          VM_MAYEXEC
+
+#define NOMMU_VMFLAGS \
+        (NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC)
+
+
 struct iov_iter;
 
 struct file_operations {
@@ -1553,6 +1570,9 @@ struct file_operations {
         long (*fallocate)(struct file *file, int mode, loff_t offset,
                           loff_t len);
         void (*show_fdinfo)(struct seq_file *m, struct file *f);
+#ifndef CONFIG_MMU
+        unsigned (*mmap_capabilities)(struct file *);
+#endif
 };
 
 struct inode_operations {
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 031ff3a9a0bd..3301c4c289d6 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -408,4 +408,6 @@ static inline int mtd_is_bitflip_or_eccerr(int err) {
         return mtd_is_bitflip(err) || mtd_is_eccerr(err);
 }
 
+unsigned mtd_mmap_capabilities(struct mtd_info *mtd);
+
 #endif /* __MTD_MTD_H__ */
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index cee02d65ab3f..0e9310905413 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -47,7 +47,7 @@ TRACE_EVENT(writeback_dirty_page,
 
         TP_fast_assign(
                 strncpy(__entry->name,
-                        mapping ? dev_name(mapping->backing_dev_info->dev) : "(unknown)", 32);
+                        mapping ? dev_name(inode_to_bdi(mapping->host)->dev) : "(unknown)", 32);
                 __entry->ino = mapping ? mapping->host->i_ino : 0;
                 __entry->index = page->index;
         ),
@@ -72,7 +72,7 @@ DECLARE_EVENT_CLASS(writeback_dirty_inode_template,
         ),
 
         TP_fast_assign(
-                struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
+                struct backing_dev_info *bdi = inode_to_bdi(inode);
 
                 /* may be called for files on pseudo FSes w/ unregistered bdi */
                 strncpy(__entry->name,
@@ -116,7 +116,7 @@ DECLARE_EVENT_CLASS(writeback_write_inode_template,
 
         TP_fast_assign(
                 strncpy(__entry->name,
-                        dev_name(inode->i_mapping->backing_dev_info->dev), 32);
+                        dev_name(inode_to_bdi(inode)->dev), 32);
                 __entry->ino            = inode->i_ino;
                 __entry->sync_mode      = wbc->sync_mode;
         ),
@@ -156,10 +156,8 @@ DECLARE_EVENT_CLASS(writeback_work_class,
                 __field(int, reason)
         ),
         TP_fast_assign(
-                struct device *dev = bdi->dev;
-                if (!dev)
-                        dev = default_backing_dev_info.dev;
-                strncpy(__entry->name, dev_name(dev), 32);
+                strncpy(__entry->name,
+                        bdi->dev ? dev_name(bdi->dev) : "(unknown)", 32);
                 __entry->nr_pages = work->nr_pages;
                 __entry->sb_dev = work->sb ? work->sb->s_dev : 0;
                 __entry->sync_mode = work->sync_mode;