lib: introduce support for page allocation tagging

Introduce helper functions to easily instrument page allocators by storing
a pointer to the allocation tag associated with the code that allocated
the page in a page_ext field.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Suren Baghdasaryan <[email protected]>
Co-developed-by: Kent Overstreet <[email protected]>
Signed-off-by: Kent Overstreet <[email protected]>
Reviewed-by: Vlastimil Babka <[email protected]>
Tested-by: Kees Cook <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Alex Gaynor <[email protected]>
Cc: Alice Ryhl <[email protected]>
Cc: Andreas Hindborg <[email protected]>
Cc: Benno Lossin <[email protected]>
Cc: "Björn Roy Baron" <[email protected]>
Cc: Boqun Feng <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Gary Guo <[email protected]>
Cc: Miguel Ojeda <[email protected]>
Cc: Pasha Tatashin <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Wedson Almeida Filho <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
index 331dd17650f3..59bb71036837 100644
--- a/lib/alloc_tag.c
+++ b/lib/alloc_tag.c
@@ -3,6 +3,7 @@
 #include <linux/fs.h>
 #include <linux/gfp.h>
 #include <linux/module.h>
+#include <linux/page_ext.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_buf.h>
 #include <linux/seq_file.h>
@@ -118,6 +119,22 @@ static bool alloc_tag_module_unload(struct codetag_type *cttype,
 	return module_unused;
 }
 
+static __init bool need_page_alloc_tagging(void)
+{
+	return true;
+}
+
+static __init void init_page_alloc_tagging(void)
+{
+}
+
+struct page_ext_operations page_alloc_tagging_ops = {
+	.size = sizeof(union codetag_ref),
+	.need = need_page_alloc_tagging,
+	.init = init_page_alloc_tagging,
+};
+EXPORT_SYMBOL(page_alloc_tagging_ops);
+
 static struct ctl_table memory_allocation_profiling_sysctls[] = {
 	{
 		.procname	= "mem_profiling",