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Diffstat (limited to 'lib/xarray.c')
-rw-r--r--lib/xarray.c97
1 files changed, 95 insertions, 2 deletions
diff --git a/lib/xarray.c b/lib/xarray.c
index 9a0d49d4b5f0..8b176f009c08 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -376,6 +376,14 @@ static void *xas_alloc(struct xa_state *xas, unsigned int shift)
return node;
}
+#ifdef CONFIG_XARRAY_MULTI
+/* Returns the number of indices covered by a given xa_state */
+static unsigned long xas_size(const struct xa_state *xas)
+{
+ return (xas->xa_sibs + 1UL) << xas->xa_shift;
+}
+#endif
+
/*
* Use this to calculate the maximum index that will need to be created
* in order to add the entry described by @xas. Because we cannot store a
@@ -388,8 +396,7 @@ static unsigned long xas_max(struct xa_state *xas)
#ifdef CONFIG_XARRAY_MULTI
if (xas->xa_shift || xas->xa_sibs) {
- unsigned long mask;
- mask = (((xas->xa_sibs + 1UL) << xas->xa_shift) - 1);
+ unsigned long mask = xas_size(xas) - 1;
max |= mask;
if (mask == max)
max++;
@@ -1517,6 +1524,92 @@ int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp)
}
EXPORT_SYMBOL(xa_reserve);
+#ifdef CONFIG_XARRAY_MULTI
+static void xas_set_range(struct xa_state *xas, unsigned long first,
+ unsigned long last)
+{
+ unsigned int shift = 0;
+ unsigned long sibs = last - first;
+ unsigned int offset = XA_CHUNK_MASK;
+
+ xas_set(xas, first);
+
+ while ((first & XA_CHUNK_MASK) == 0) {
+ if (sibs < XA_CHUNK_MASK)
+ break;
+ if ((sibs == XA_CHUNK_MASK) && (offset < XA_CHUNK_MASK))
+ break;
+ shift += XA_CHUNK_SHIFT;
+ if (offset == XA_CHUNK_MASK)
+ offset = sibs & XA_CHUNK_MASK;
+ sibs >>= XA_CHUNK_SHIFT;
+ first >>= XA_CHUNK_SHIFT;
+ }
+
+ offset = first & XA_CHUNK_MASK;
+ if (offset + sibs > XA_CHUNK_MASK)
+ sibs = XA_CHUNK_MASK - offset;
+ if ((((first + sibs + 1) << shift) - 1) > last)
+ sibs -= 1;
+
+ xas->xa_shift = shift;
+ xas->xa_sibs = sibs;
+}
+
+/**
+ * xa_store_range() - Store this entry at a range of indices in the XArray.
+ * @xa: XArray.
+ * @first: First index to affect.
+ * @last: Last index to affect.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * After this function returns, loads from any index between @first and @last,
+ * inclusive will return @entry.
+ * Storing into an existing multislot entry updates the entry of every index.
+ * The marks associated with @index are unaffected unless @entry is %NULL.
+ *
+ * Context: Process context. Takes and releases the xa_lock. May sleep
+ * if the @gfp flags permit.
+ * Return: %NULL on success, xa_err(-EINVAL) if @entry cannot be stored in
+ * an XArray, or xa_err(-ENOMEM) if memory allocation failed.
+ */
+void *xa_store_range(struct xarray *xa, unsigned long first,
+ unsigned long last, void *entry, gfp_t gfp)
+{
+ XA_STATE(xas, xa, 0);
+
+ if (WARN_ON_ONCE(xa_is_internal(entry)))
+ return XA_ERROR(-EINVAL);
+ if (last < first)
+ return XA_ERROR(-EINVAL);
+
+ do {
+ xas_lock(&xas);
+ if (entry) {
+ unsigned int order = (last == ~0UL) ? 64 :
+ ilog2(last + 1);
+ xas_set_order(&xas, last, order);
+ xas_create(&xas);
+ if (xas_error(&xas))
+ goto unlock;
+ }
+ do {
+ xas_set_range(&xas, first, last);
+ xas_store(&xas, entry);
+ if (xas_error(&xas))
+ goto unlock;
+ first += xas_size(&xas);
+ } while (first <= last);
+unlock:
+ xas_unlock(&xas);
+ } while (xas_nomem(&xas, gfp));
+
+ return xas_result(&xas, NULL);
+}
+EXPORT_SYMBOL(xa_store_range);
+#endif /* CONFIG_XARRAY_MULTI */
+
/**
* __xa_alloc() - Find somewhere to store this entry in the XArray.
* @xa: XArray.