I'd like to thank Keith Packard for offering suggestions on this version.
I've included a couple of conversions, just so you can see how it looks
from a user point of view.
diff --git a/drivers/media/v4l2-core/v4l2-event.c b/drivers/media/v4l2-core/v4l2-event.c
index 968c2eb08b5a..1dc4d2185a7a 100644
--- a/drivers/media/v4l2-core/v4l2-event.c
+++ b/drivers/media/v4l2-core/v4l2-event.c
@@ -215,8 +215,7 @@ int v4l2_event_subscribe(struct v4l2_fh *fh,
if (elems < 1)
elems = 1;
- sev = kvzalloc(sizeof(*sev) + sizeof(struct v4l2_kevent) * elems,
- GFP_KERNEL);
+ sev = kvzalloc_hdr_arr(sev, events, elems, GFP_KERNEL);
if (!sev)
return -ENOMEM;
for (i = 0; i < elems; i++)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 33ac2b186b85..c6c5e839fca4 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1292,7 +1292,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
return -EOPNOTSUPP;
if (mem.nregions > max_mem_regions)
return -E2BIG;
- newmem = kvzalloc(size + mem.nregions * sizeof(*m->regions), GFP_KERNEL);
+ newmem = kvzalloc_hdr_arr(newmem, regions, mem.nregions, GFP_KERNEL);
if (!newmem)
return -ENOMEM;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fe1ee4313add..46ee6bac61a0 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -557,6 +557,31 @@ static inline void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
return kvmalloc(n * size, flags);
}
+static inline void *kvzalloc_ab_c(size_t n, size_t size, size_t c, gfp_t flags)
+{
+ if (size != 0 && n > (SIZE_MAX - c) / size)
+ return NULL;
+
+ return kvzalloc(n * size + c, flags);
+}
+
+/**
+ * kvzalloc_hdr_arr() - Allocate a zero-filled array with a header.
+ * @p: Pointer to the header.
+ * @member: Name of the array member.
+ * @n: Number of elements in the array.
+ * @gfp: Memory allocation flags.
+ *
+ * Allocate (and zero-fill) enough memory for a structure with an array
+ * of @n elements.
+ *
+ * Return: Zero-filled memory or a NULL pointer.
+ */
+#define kvzalloc_hdr_arr(p, member, n, gfp) \
+ (typeof(p))kvzalloc_ab_c(n, \
+ sizeof(*(p)->member) + __must_be_array((p)->member), \
+ offsetof(typeof(*(p)), member), gfp)
+
extern void kvfree(const void *addr);
static inline atomic_t *compound_mapcount_ptr(struct page *page)
--
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