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/xarray.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/xarray.h')
| -rw-r--r-- | include/linux/xarray.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/include/linux/xarray.h b/include/linux/xarray.h new file mode 100644 index 000000000000..2dfc8006fe64 --- /dev/null +++ b/include/linux/xarray.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +#ifndef _LINUX_XARRAY_H +#define _LINUX_XARRAY_H +/* + * eXtensible Arrays + * Copyright (c) 2017 Microsoft Corporation + * Author: Matthew Wilcox <mawilcox@microsoft.com> + */ + +#include <linux/spinlock.h> + +#define xa_trylock(xa) spin_trylock(&(xa)->xa_lock) +#define xa_lock(xa) spin_lock(&(xa)->xa_lock) +#define xa_unlock(xa) spin_unlock(&(xa)->xa_lock) +#define xa_lock_bh(xa) spin_lock_bh(&(xa)->xa_lock) +#define xa_unlock_bh(xa) spin_unlock_bh(&(xa)->xa_lock) +#define xa_lock_irq(xa) spin_lock_irq(&(xa)->xa_lock) +#define xa_unlock_irq(xa) spin_unlock_irq(&(xa)->xa_lock) +#define xa_lock_irqsave(xa, flags) \ + spin_lock_irqsave(&(xa)->xa_lock, flags) +#define xa_unlock_irqrestore(xa, flags) \ + spin_unlock_irqrestore(&(xa)->xa_lock, flags) + +#endif /* _LINUX_XARRAY_H */ |