summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--include/linux/xarray.h36
-rw-r--r--lib/test_xarray.c28
-rw-r--r--lib/xarray.c6
3 files changed, 48 insertions, 22 deletions
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index 687c150071a5..588733abd19d 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -131,6 +131,12 @@ static inline unsigned int xa_pointer_tag(void *entry)
* xa_mk_internal() - Create an internal entry.
* @v: Value to turn into an internal entry.
*
+ * Internal entries are used for a number of purposes. Entries 0-255 are
+ * used for sibling entries (only 0-62 are used by the current code). 256
+ * is used for the retry entry. 257 is used for the reserved / zero entry.
+ * Negative internal entries are used to represent errnos. Node pointers
+ * are also tagged as internal entries in some situations.
+ *
* Context: Any context.
* Return: An XArray internal entry corresponding to this value.
*/
@@ -163,6 +169,22 @@ static inline bool xa_is_internal(const void *entry)
return ((unsigned long)entry & 3) == 2;
}
+#define XA_ZERO_ENTRY xa_mk_internal(257)
+
+/**
+ * xa_is_zero() - Is the entry a zero entry?
+ * @entry: Entry retrieved from the XArray
+ *
+ * The normal API will return NULL as the contents of a slot containing
+ * a zero entry. You can only see zero entries by using the advanced API.
+ *
+ * Return: %true if the entry is a zero entry.
+ */
+static inline bool xa_is_zero(const void *entry)
+{
+ return unlikely(entry == XA_ZERO_ENTRY);
+}
+
/**
* xa_is_err() - Report whether an XArray operation returned an error
* @entry: Result from calling an XArray function
@@ -1050,7 +1072,7 @@ int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp)
*/
static inline void xa_release(struct xarray *xa, unsigned long index)
{
- xa_cmpxchg(xa, index, NULL, NULL, 0);
+ xa_cmpxchg(xa, index, XA_ZERO_ENTRY, NULL, 0);
}
/* Everything below here is the Advanced API. Proceed with caution. */
@@ -1210,18 +1232,6 @@ static inline bool xa_is_sibling(const void *entry)
}
#define XA_RETRY_ENTRY xa_mk_internal(256)
-#define XA_ZERO_ENTRY xa_mk_internal(257)
-
-/**
- * xa_is_zero() - Is the entry a zero entry?
- * @entry: Entry retrieved from the XArray
- *
- * Return: %true if the entry is a zero entry.
- */
-static inline bool xa_is_zero(const void *entry)
-{
- return unlikely(entry == XA_ZERO_ENTRY);
-}
/**
* xa_is_retry() - Is the entry a retry entry?
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index 3eaa40ddc390..52f8ecff8c0c 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -361,6 +361,7 @@ static noinline void check_reserve(struct xarray *xa)
{
void *entry;
unsigned long index;
+ int count;
/* An array with a reserved entry is not empty */
XA_BUG_ON(xa, !xa_empty(xa));
@@ -377,15 +378,15 @@ static noinline void check_reserve(struct xarray *xa)
xa_erase_index(xa, 12345678);
XA_BUG_ON(xa, !xa_empty(xa));
- /* cmpxchg sees a reserved entry as NULL */
+ /* cmpxchg sees a reserved entry as ZERO */
XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0);
- XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, NULL, xa_mk_value(12345678),
- GFP_NOWAIT) != NULL);
+ XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, XA_ZERO_ENTRY,
+ xa_mk_value(12345678), GFP_NOWAIT) != NULL);
xa_release(xa, 12345678);
xa_erase_index(xa, 12345678);
XA_BUG_ON(xa, !xa_empty(xa));
- /* But xa_insert does not */
+ /* xa_insert treats it as busy */
XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0);
XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) !=
-EBUSY);
@@ -398,9 +399,27 @@ static noinline void check_reserve(struct xarray *xa)
XA_BUG_ON(xa, xa_reserve(xa, 6, GFP_KERNEL) != 0);
xa_store_index(xa, 7, GFP_KERNEL);
+ count = 0;
xa_for_each(xa, index, entry) {
XA_BUG_ON(xa, index != 5 && index != 7);
+ count++;
+ }
+ XA_BUG_ON(xa, count != 2);
+
+ /* If we free a reserved entry, we should be able to allocate it */
+ if (xa->xa_flags & XA_FLAGS_ALLOC) {
+ u32 id;
+
+ XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_value(8),
+ XA_LIMIT(5, 10), GFP_KERNEL) != 0);
+ XA_BUG_ON(xa, id != 8);
+
+ xa_release(xa, 6);
+ XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_value(6),
+ XA_LIMIT(5, 10), GFP_KERNEL) != 0);
+ XA_BUG_ON(xa, id != 6);
}
+
xa_destroy(xa);
}
@@ -1486,6 +1505,7 @@ static int xarray_checks(void)
check_xas_erase(&array);
check_cmpxchg(&array);
check_reserve(&array);
+ check_reserve(&xa0);
check_multi_store(&array);
check_xa_alloc();
check_find(&array);
diff --git a/lib/xarray.c b/lib/xarray.c
index 89e37ac50850..b9a6cf42feee 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1429,16 +1429,12 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index,
if (WARN_ON_ONCE(xa_is_advanced(entry)))
return XA_ERROR(-EINVAL);
- if (xa_track_free(xa) && !entry)
- entry = XA_ZERO_ENTRY;
do {
curr = xas_load(&xas);
- if (curr == XA_ZERO_ENTRY)
- curr = NULL;
if (curr == old) {
xas_store(&xas, entry);
- if (xa_track_free(xa))
+ if (xa_track_free(xa) && entry && !curr)
xas_clear_mark(&xas, XA_FREE_MARK);
}
} while (__xas_nomem(&xas, gfp));