page cache: use xa_lock
Remove the address_space ->tree_lock and use the xa_lock newly added to
the radix_tree_root. Rename the address_space ->page_tree to ->i_pages,
since we don't really care that it's a tree.
[willy@infradead.org: fix nds32, fs/dax.c]
Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index e6cbb91..09da0f1 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -329,7 +329,7 @@ static inline bool inode_to_wb_is_valid(struct inode *inode)
* @inode: inode of interest
*
* Returns the wb @inode is currently associated with. The caller must be
- * holding either @inode->i_lock, @inode->i_mapping->tree_lock, or the
+ * holding either @inode->i_lock, the i_pages lock, or the
* associated wb's list_lock.
*/
static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
@@ -337,7 +337,7 @@ static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
#ifdef CONFIG_LOCKDEP
WARN_ON_ONCE(debug_locks &&
(!lockdep_is_held(&inode->i_lock) &&
- !lockdep_is_held(&inode->i_mapping->tree_lock) &&
+ !lockdep_is_held(&inode->i_mapping->i_pages.xa_lock) &&
!lockdep_is_held(&inode->i_wb->list_lock)));
#endif
return inode->i_wb;
@@ -349,7 +349,7 @@ static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
* @lockedp: temp bool output param, to be passed to the end function
*
* The caller wants to access the wb associated with @inode but isn't
- * holding inode->i_lock, mapping->tree_lock or wb->list_lock. This
+ * holding inode->i_lock, the i_pages lock or wb->list_lock. This
* function determines the wb associated with @inode and ensures that the
* association doesn't change until the transaction is finished with
* unlocked_inode_to_wb_end().
@@ -370,11 +370,11 @@ unlocked_inode_to_wb_begin(struct inode *inode, bool *lockedp)
*lockedp = smp_load_acquire(&inode->i_state) & I_WB_SWITCH;
if (unlikely(*lockedp))
- spin_lock_irq(&inode->i_mapping->tree_lock);
+ xa_lock_irq(&inode->i_mapping->i_pages);
/*
- * Protected by either !I_WB_SWITCH + rcu_read_lock() or tree_lock.
- * inode_to_wb() will bark. Deref directly.
+ * Protected by either !I_WB_SWITCH + rcu_read_lock() or the i_pages
+ * lock. inode_to_wb() will bark. Deref directly.
*/
return inode->i_wb;
}
@@ -387,7 +387,7 @@ unlocked_inode_to_wb_begin(struct inode *inode, bool *lockedp)
static inline void unlocked_inode_to_wb_end(struct inode *inode, bool locked)
{
if (unlikely(locked))
- spin_unlock_irq(&inode->i_mapping->tree_lock);
+ xa_unlock_irq(&inode->i_mapping->i_pages);
rcu_read_unlock();
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2aa02ca..92efaf1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -13,6 +13,7 @@
#include <linux/list_lru.h>
#include <linux/llist.h>
#include <linux/radix-tree.h>
+#include <linux/xarray.h>
#include <linux/rbtree.h>
#include <linux/init.h>
#include <linux/pid.h>
@@ -390,12 +391,11 @@ int pagecache_write_end(struct file *, struct address_space *mapping,
struct address_space {
struct inode *host; /* owner: inode, block_device */
- struct radix_tree_root page_tree; /* radix tree of all pages */
- spinlock_t tree_lock; /* and lock protecting it */
+ struct radix_tree_root i_pages; /* cached pages */
atomic_t i_mmap_writable;/* count VM_SHARED mappings */
struct rb_root_cached i_mmap; /* tree of private and shared mappings */
struct rw_semaphore i_mmap_rwsem; /* protect tree, count, list */
- /* Protected by tree_lock together with the radix tree */
+ /* Protected by the i_pages lock */
unsigned long nrpages; /* number of total pages */
/* number of shadow or DAX exceptional entries */
unsigned long nrexceptional;
@@ -1989,7 +1989,7 @@ static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
*
* I_WB_SWITCH Cgroup bdi_writeback switching in progress. Used to
* synchronize competing switching instances and to tell
- * wb stat updates to grab mapping->tree_lock. See
+ * wb stat updates to grab the i_pages lock. See
* inode_switch_wb_work_fn() for details.
*
* I_OVL_INUSE Used by overlayfs to get exclusive ownership on upper
diff --git a/include/linux/mm.h b/include/linux/mm.h
index f13bc25..1ac1f06 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -747,7 +747,7 @@ int finish_mkwrite_fault(struct vm_fault *vmf);
* refcount. The each user mapping also has a reference to the page.
*
* The pagecache pages are stored in a per-mapping radix tree, which is
- * rooted at mapping->page_tree, and indexed by offset.
+ * rooted at mapping->i_pages, and indexed by offset.
* Where 2.4 and early 2.6 kernels kept dirty/clean pages in per-address_space
* lists, we instead now tag pages as dirty/writeback in the radix tree.
*
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 34ce3eb..b1bd218 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -144,7 +144,7 @@ void release_pages(struct page **pages, int nr);
* 3. check the page is still in pagecache (if no, goto 1)
*
* Remove-side that cares about stability of _refcount (eg. reclaim) has the
- * following (with tree_lock held for write):
+ * following (with the i_pages lock held):
* A. atomically check refcount is correct and set it to 0 (atomic_cmpxchg)
* B. remove page from pagecache
* C. free the page
@@ -157,7 +157,7 @@ void release_pages(struct page **pages, int nr);
*
* It is possible that between 1 and 2, the page is removed then the exact same
* page is inserted into the same position in pagecache. That's OK: the
- * old find_get_page using tree_lock could equally have run before or after
+ * old find_get_page using a lock could equally have run before or after
* such a re-insertion, depending on order that locks are granted.
*
* Lookups racing against pagecache insertion isn't a big problem: either 1