flex_array: fix get function for elements in base starting at non-zero
If all array elements fit into the base structure and data is copied using
flex_array_put() starting at a non-zero index, flex_array_get() will fail
to return the data.
This fixes the bug by only checking for NULL parts when all elements do
not fit in the base structure when flex_array_get() is used. Otherwise,
fa_element_to_part_nr() will always be 0 since there are no parts
structures needed and such element may never have been put. Thus, it will
remain NULL due to the kzalloc() of the base.
Additionally, flex_array_put() now only checks for a NULL part when all
elements do not fit in the base structure. This is otherwise unnecessary
since the base structure is guaranteed to exist (or we would have already
hit a NULL pointer).
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/flex_array.c b/lib/flex_array.c
index 08f1636..e73c691 100644
--- a/lib/flex_array.c
+++ b/lib/flex_array.c
@@ -198,10 +198,11 @@
return -ENOSPC;
if (elements_fit_in_base(fa))
part = (struct flex_array_part *)&fa->parts[0];
- else
+ else {
part = __fa_get_part(fa, part_nr, flags);
- if (!part)
- return -ENOMEM;
+ if (!part)
+ return -ENOMEM;
+ }
dst = &part->elements[index_inside_part(fa, element_nr)];
memcpy(dst, src, fa->element_size);
return 0;
@@ -257,11 +258,12 @@
if (element_nr >= fa->total_nr_elements)
return NULL;
- if (!fa->parts[part_nr])
- return NULL;
if (elements_fit_in_base(fa))
part = (struct flex_array_part *)&fa->parts[0];
- else
+ else {
part = fa->parts[part_nr];
+ if (!part)
+ return NULL;
+ }
return &part->elements[index_inside_part(fa, element_nr)];
}