Getting and putting arrays of pointers with flex arrays is a PITA. You
have to remember to pass &ptr to the _put and you have to do weird and
wacky casting to get the ptr back from the _get. Add two functions
flex_array_get_ptr() and flex_array_put_ptr() to handle all of the magic.
Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
---
include/linux/flex_array.h | 6 ++++++
lib/flex_array.c | 25 ++++++++++++++++++++++++-
2 files changed, 30 insertions(+), 1 deletions(-)
diff --git a/include/linux/flex_array.h b/include/linux/flex_array.h
index 1d747f7..f4e4eb2 100644
--- a/include/linux/flex_array.h
+++ b/include/linux/flex_array.h
@@ -70,4 +70,10 @@ int flex_array_clear(struct flex_array *fa, unsigned int element_nr);
void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
int flex_array_shrink(struct flex_array *fa);
+#define flex_array_put_ptr(fa, nr, src, gfp) ({ \
+ void *_src = (src); \
+ flex_array_put((fa), (nr), &_src, (gfp)); \
+ })
+void *flex_array_get_ptr(struct flex_array *fa, unsigned int element_nr);
+
#endif /* _FLEX_ARRAY_H */
diff --git a/lib/flex_array.c b/lib/flex_array.c
index 41b1804..77a6fea 100644
--- a/lib/flex_array.c
+++ b/lib/flex_array.c
@@ -171,6 +171,8 @@ __fa_get_part(struct flex_array *fa, int part_nr, gfp_t flags)
* Note that this *copies* the contents of @src into
* the array. If you are trying to store an array of
* pointers, make sure to pass in &ptr instead of ptr.
+ * You may instead wish to use the flex_array_put_ptr()
+ * helper function.
*
* Locking must be provided by the caller.
*/
@@ -265,7 +267,8 @@ int flex_array_prealloc(struct flex_array *fa, unsigned int start,
*
* Returns a pointer to the data at index @element_nr. Note
* that this is a copy of the data that was passed in. If you
- * are using this to store pointers, you'll get back &ptr.
+ * are using this to store pointers, you'll get back &ptr. You
+ * may instead wish to use the flex_array_get_ptr helper.
*
* Locking must be provided by the caller.
*/
@@ -286,6 +289,26 @@ void *flex_array_get(struct flex_array *fa, unsigned int element_nr)
return &part->elements[index_inside_part(fa, element_nr)];
}
+/**
+ * flex_array_get_ptr - pull a ptr back out of the array
+ * @fa: the flex array from which to extract data
+ * @element_nr: index of the element to fetch from the array
+ *
+ * Returns the pointer placed in the flex array at element_nr using
+ * flex_array_put_ptr(). This function should not be called if the
+ * element in question was not set using the _put_ptr() helper.
+ */
+void *flex_array_get_ptr(struct flex_array *fa, unsigned int element_nr)
+{
+ void **tmp;
+
+ tmp = flex_array_get(fa, element_nr);
+ if (!tmp)
+ return NULL;
+
+ return *tmp;
+}
+
static int part_is_free(struct flex_array_part *part)
{
int i;
--
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