XArray: Handle NULL pointers differently for allocation
For allocating XArrays, it makes sense to distinguish beteen erasing an
entry and storing NULL. Storing NULL keeps the index allocated with a
NULL pointer associated with it while xa_erase() frees the index. Some
existing IDR users rely on this ability.
Signed-off-by: Matthew Wilcox <[email protected]>
diff --git a/lib/xarray.c b/lib/xarray.c
index a9d2801..c3e2084 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1382,10 +1382,12 @@ void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
if (WARN_ON_ONCE(xa_is_internal(entry)))
return XA_ERROR(-EINVAL);
+ if (xa_track_free(xa) && !entry)
+ entry = XA_ZERO_ENTRY;
do {
curr = xas_store(&xas, entry);
- if (xa_track_free(xa) && entry)
+ if (xa_track_free(xa))
xas_clear_mark(&xas, XA_FREE_MARK);
} while (__xas_nomem(&xas, gfp));
@@ -1446,6 +1448,8 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index,
if (WARN_ON_ONCE(xa_is_internal(entry)))
return XA_ERROR(-EINVAL);
+ if (xa_track_free(xa) && !entry)
+ entry = XA_ZERO_ENTRY;
do {
curr = xas_load(&xas);
@@ -1453,7 +1457,7 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index,
curr = NULL;
if (curr == old) {
xas_store(&xas, entry);
- if (xa_track_free(xa) && entry)
+ if (xa_track_free(xa))
xas_clear_mark(&xas, XA_FREE_MARK);
}
} while (__xas_nomem(&xas, gfp));
@@ -1487,8 +1491,11 @@ int __xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp)
do {
curr = xas_load(&xas);
- if (!curr)
+ if (!curr) {
xas_store(&xas, XA_ZERO_ENTRY);
+ if (xa_track_free(xa))
+ xas_clear_mark(&xas, XA_FREE_MARK);
+ }
} while (__xas_nomem(&xas, gfp));
return xas_error(&xas);
