redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

XArray: Turn xa_init_flags into a static inline 

A regular xa_init_flags() put all dynamically-initialised XArrays into
the same locking class.  That leads to lockdep believing that taking
one XArray lock while holding another is a deadlock.  It's possible to
work around some of these situations with separate locking classes for
irq/bh/regular XArrays, and SINGLE_DEPTH_NESTING, but that's ugly, and
it doesn't work for all situations (where we have completely unrelated
XArrays).

Signed-off-by: Matthew Wilcox <willy@infradead.org>
hifive-unleashed-5.1
Matthew Wilcox 2018-12-05 16:37:03 -05:00
parent 490fd30f85
commit 02669b17a4
2 changed files with 18 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
include/linux/xarray.h
View File

@ -286,7 +286,6 @@ struct xarray {
*/
#define DEFINE_XARRAY_ALLOC(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC)
void xa_init_flags(struct xarray *, gfp_t flags);
void *xa_load(struct xarray *, unsigned long index);
void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t);
void *xa_erase(struct xarray *, unsigned long index);
@ -303,6 +302,24 @@ unsigned int xa_extract(struct xarray *, void **dst, unsigned long start,
unsigned long max, unsigned int n, xa_mark_t);
void xa_destroy(struct xarray *);
/**
* xa_init_flags() - Initialise an empty XArray with flags.
* @xa: XArray.
* @flags: XA_FLAG values.
*
* If you need to initialise an XArray with special flags (eg you need
* to take the lock from interrupt context), use this function instead
* of xa_init().
*
* Context: Any context.
*/
static inline void xa_init_flags(struct xarray *xa, gfp_t flags)
{
spin_lock_init(&xa->xa_lock);
xa->xa_flags = flags;
xa->xa_head = NULL;
}
/**
* xa_init() - Initialise an empty XArray.
* @xa: XArray.

29
lib/xarray.c
View File

@ -1250,35 +1250,6 @@ void *xas_find_conflict(struct xa_state *xas)
}
EXPORT_SYMBOL_GPL(xas_find_conflict);
/**
* xa_init_flags() - Initialise an empty XArray with flags.
* @xa: XArray.
* @flags: XA_FLAG values.
*
* If you need to initialise an XArray with special flags (eg you need
* to take the lock from interrupt context), use this function instead
* of xa_init().
*
* Context: Any context.
*/
void xa_init_flags(struct xarray *xa, gfp_t flags)
{
unsigned int lock_type;
static struct lock_class_key xa_lock_irq;
static struct lock_class_key xa_lock_bh;
spin_lock_init(&xa->xa_lock);
xa->xa_flags = flags;
xa->xa_head = NULL;
lock_type = xa_lock_type(xa);
if (lock_type == XA_LOCK_IRQ)
lockdep_set_class(&xa->xa_lock, &xa_lock_irq);
else if (lock_type == XA_LOCK_BH)
lockdep_set_class(&xa->xa_lock, &xa_lock_bh);
}
EXPORT_SYMBOL(xa_init_flags);
/**
* xa_load() - Load an entry from an XArray.
* @xa: XArray.