diff options
| author | Matthew Wilcox <mawilcox@microsoft.com> | 2018-04-11 02:36:52 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-11 20:28:39 +0300 |
| commit | f6bb2a2c0b81c47282ddb7883f92e65a063c27dd (patch) | |
| tree | 74eb6dece48af9baee664a3abe1d70b5798f8b0d /include/linux/radix-tree.h | |
| parent | e5a955419642e0842fd26e1ada6ab3328018ca16 (diff) | |
| download | linux-f6bb2a2c0b81c47282ddb7883f92e65a063c27dd.tar.xz | |
xarray: add the xa_lock to the radix_tree_root
This results in no change in structure size on 64-bit machines as it
fits in the padding between the gfp_t and the void *. 32-bit machines
will grow the structure from 8 to 12 bytes. Almost all radix trees are
protected with (at least) a spinlock, so as they are converted from
radix trees to xarrays, the data structures will shrink again.
Initialising the spinlock requires a name for the benefit of lockdep, so
RADIX_TREE_INIT() now needs to know the name of the radix tree it's
initialising, and so do IDR_INIT() and IDA_INIT().
Also add the xa_lock() and xa_unlock() family of wrappers to make it
easier to use the lock. If we could rely on -fplan9-extensions in the
compiler, we could avoid all of this syntactic sugar, but that wasn't
added until gcc 4.6.
Link: http://lkml.kernel.org/r/20180313132639.17387-8-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
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>
Diffstat (limited to 'include/linux/radix-tree.h')
| -rw-r--r-- | include/linux/radix-tree.h | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 6c4e2e716dac..34149e8b5f73 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -110,20 +110,23 @@ struct radix_tree_node { #define ROOT_TAG_SHIFT (__GFP_BITS_SHIFT) struct radix_tree_root { + spinlock_t xa_lock; gfp_t gfp_mask; struct radix_tree_node __rcu *rnode; }; -#define RADIX_TREE_INIT(mask) { \ +#define RADIX_TREE_INIT(name, mask) { \ + .xa_lock = __SPIN_LOCK_UNLOCKED(name.xa_lock), \ .gfp_mask = (mask), \ .rnode = NULL, \ } #define RADIX_TREE(name, mask) \ - struct radix_tree_root name = RADIX_TREE_INIT(mask) + struct radix_tree_root name = RADIX_TREE_INIT(name, mask) #define INIT_RADIX_TREE(root, mask) \ do { \ + spin_lock_init(&(root)->xa_lock); \ (root)->gfp_mask = (mask); \ (root)->rnode = NULL; \ } while (0) |