[RFC PATCH v2 09/16] mm: Read the nr_pages_allocs value given by user

[Juan Yescas <jyescas@google.com>]

This change reads the nr_page_allocs value given by the user and
validates that is an unsigned long.

If the input is valid, it will allocate an array of nr_page_allocs
size. This array will store the allocation ids. These allocation ids
will be used to free the allocations.

Signed-off-by: Juan Yescas <jyescas@google.com>
---

Changes in v2:
	- Free allocs_ids.

 mm/page_alloc_hogger.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/mm/page_alloc_hogger.c b/mm/page_alloc_hogger.c
index ded3f0fc6641..9b1eaf3814e1 100644
--- a/mm/page_alloc_hogger.c
+++ b/mm/page_alloc_hogger.c
@@ -135,6 +135,21 @@ static struct kmem_cache *page_alloc_cache;
 static ssize_t req_page_alloc_write(struct file *file, const char __user *ubuf,
 				     size_t cnt, loff_t *ppos)
 {
+	unsigned long nr_pages_allocs;
+	unsigned long *allocs_ids;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &nr_pages_allocs);
+	if (ret)
+		return ret;
+
+	allocs_ids = kmalloc_array(nr_pages_allocs, sizeof(unsigned long),
+					GFP_KERNEL);
+	if (!allocs_ids)
+		return -ENOMEM;
+
+	kfree(allocs_ids);
+
 	return cnt;
 }
 
-- 
2.55.0.629.g250fe7f194-goog