[PATCH v3 13/16] mm: Remove __alloc_pages_node()

[Brendan Jackman]

There were only a few users, which have been removed. The only advantage
of this API over alloc_pages_node() is avoiding a single conditional
branch. The disadvantages are:

1. More API surface, more sources of confusion, more maintenance.

2. Worse impact of CPU hotplug bugs: most users of __alloc_pages_node()
   were using the result of cpu_to_node(); if the CPU gets hotplugged
   out this will return NUMA_NO_NODE. If one of these paths fails to
   protect against a concurrent hotplug then page_alloc.c will use
   NUMA_NO_NODE as an index into NODE_DATA() and cause some horrible
   memory corruption or other. With alloc_pages_node(), the code might
   just work fine.

Ulterior motive: this frees up the __* variants of the allocator APIs to
serve specifically for use as mm-internal API.

Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Signed-off-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
---
 include/linux/gfp.h | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 01d6d2591f49e..3bf55a5f9143e 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -256,21 +256,6 @@ static inline void warn_if_node_offline(int this_node, gfp_t gfp_mask)
 	dump_stack();
 }
 
-/*
- * Allocate pages, preferring the node given as nid. The node must be valid and
- * online. For more general interface, see alloc_pages_node().
- */
-static inline struct page *
-__alloc_pages_node_noprof(int nid, gfp_t gfp_mask, unsigned int order)
-{
-	VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
-	warn_if_node_offline(nid, gfp_mask);
-
-	return __alloc_pages_noprof(gfp_mask, order, nid, NULL);
-}
-
-#define  __alloc_pages_node(...)		alloc_hooks(__alloc_pages_node_noprof(__VA_ARGS__))
-
 static inline
 struct folio *__folio_alloc_node_noprof(gfp_t gfp, unsigned int order, int nid)
 {
@@ -293,7 +278,10 @@ static inline struct page *alloc_pages_node_noprof(int nid, gfp_t gfp_mask,
 	if (nid == NUMA_NO_NODE)
 		nid = numa_mem_id();
 
-	return __alloc_pages_node_noprof(nid, gfp_mask, order);
+	VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
+	warn_if_node_offline(nid, gfp_mask);
+
+	return __alloc_pages_noprof(gfp_mask, order, nid, NULL);
 }
 
 #define  alloc_pages_node(...)			alloc_hooks(alloc_pages_node_noprof(__VA_ARGS__))

-- 
2.54.0