aboutsummaryrefslogtreecommitdiff
path: root/lib
diff options
context:
space:
mode:
authorMatthew Wilcox <willy@infradead.org>2019-01-02 13:57:03 -0500
committerMatthew Wilcox <willy@infradead.org>2019-01-06 22:12:58 -0500
commitb0606fed6eece16a421034eca0bbea9a08b90e91 (patch)
treef705b58760a60fce2d6f03a934a5038154505c1b /lib
parent76b4e52995654af260f14558e0e07b5b039ae202 (diff)
downloadlinux-stericsson-b0606fed6eece16a421034eca0bbea9a08b90e91.tar.gz
XArray: Honour reserved entries in xa_insert
xa_insert() should treat reserved entries as occupied, not as available. Also, it should treat requests to insert a NULL pointer as a request to reserve the slot. Add xa_insert_bh() and xa_insert_irq() for completeness. Signed-off-by: Matthew Wilcox <willy@infradead.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/test_xarray.c8
-rw-r--r--lib/xarray.c41
2 files changed, 46 insertions, 3 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index 6e0212a60b08..3cf17338b0a4 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -382,10 +382,12 @@ static noinline void check_reserve(struct xarray *xa)
xa_erase_index(xa, 12345678);
XA_BUG_ON(xa, !xa_empty(xa));
- /* And so does xa_insert */
+ /* But xa_insert does not */
xa_reserve(xa, 12345678, GFP_KERNEL);
- XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) != 0);
- xa_erase_index(xa, 12345678);
+ XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) !=
+ -EEXIST);
+ XA_BUG_ON(xa, xa_empty(xa));
+ XA_BUG_ON(xa, xa_erase(xa, 12345678) != NULL);
XA_BUG_ON(xa, !xa_empty(xa));
/* Can iterate through a reserved entry */
diff --git a/lib/xarray.c b/lib/xarray.c
index bffa26b1f0d6..81c3171ddde9 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1440,6 +1440,47 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index,
EXPORT_SYMBOL(__xa_cmpxchg);
/**
+ * __xa_insert() - Store this entry in the XArray if no entry is present.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * Inserting a NULL entry will store a reserved entry (like xa_reserve())
+ * if no entry is present. Inserting will fail if a reserved entry is
+ * present, even though loading from this index will return NULL.
+ *
+ * Context: Any context. Expects xa_lock to be held on entry. May
+ * release and reacquire xa_lock if @gfp flags permit.
+ * Return: 0 if the store succeeded. -EEXIST if another entry was present.
+ * -ENOMEM if memory could not be allocated.
+ */
+int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
+{
+ XA_STATE(xas, xa, index);
+ void *curr;
+
+ if (WARN_ON_ONCE(xa_is_advanced(entry)))
+ return -EINVAL;
+ if (!entry)
+ entry = XA_ZERO_ENTRY;
+
+ do {
+ curr = xas_load(&xas);
+ if (!curr) {
+ xas_store(&xas, entry);
+ if (xa_track_free(xa))
+ xas_clear_mark(&xas, XA_FREE_MARK);
+ } else {
+ xas_set_err(&xas, -EEXIST);
+ }
+ } while (__xas_nomem(&xas, gfp));
+
+ return xas_error(&xas);
+}
+EXPORT_SYMBOL(__xa_insert);
+
+/**
* __xa_reserve() - Reserve this index in the XArray.
* @xa: XArray.
* @index: Index into array.