[PATCH] memblock: FIX THE STUPID FRAGILITY

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Introduce numa_valid_node(nid) that verifies that nid is a valid node ID
and use that instead of comparing nid parameter with either NUMA_NO_NODE
or MAX_NUMNODES.

This makes the checks for valid node IDs consistent and more robust and
allows to get rid of multiple WARNings.

Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
---
 include/linux/numa.h |  5 +++++
 mm/memblock.c        | 28 +++++++---------------------
 2 files changed, 12 insertions(+), 21 deletions(-)

diff --git a/include/linux/numa.h b/include/linux/numa.h
index 1d43371fafd2..eb19503604fe 100644
--- a/include/linux/numa.h
+++ b/include/linux/numa.h
@@ -15,6 +15,11 @@
 #define	NUMA_NO_NODE	(-1)
 #define	NUMA_NO_MEMBLK	(-1)
 
+static inline bool numa_valid_node(int nid)
+{
+	return nid >= 0 && nid < MAX_NUMNODES;
+}
+
 /* optionally keep NUMA memory info available post init */
 #ifdef CONFIG_NUMA_KEEP_MEMINFO
 #define __initdata_or_meminfo
diff --git a/mm/memblock.c b/mm/memblock.c
index 08e9806b1cf9..e81fb68f7f88 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -754,7 +754,7 @@ bool __init_memblock memblock_validate_numa_coverage(unsigned long threshold_byt
 
 	/* calculate lose page */
 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
-		if (nid == NUMA_NO_NODE)
+		if (!numa_valid_node(nid))
 			nr_pages += end_pfn - start_pfn;
 	}
 
@@ -1061,7 +1061,7 @@ static bool should_skip_region(struct memblock_type *type,
 		return false;
 
 	/* only memory regions are associated with nodes, check it */
-	if (nid != NUMA_NO_NODE && nid != m_nid)
+	if (numa_valid_node(nid) && nid != m_nid)
 		return true;
 
 	/* skip hotpluggable memory regions if needed */
@@ -1118,10 +1118,6 @@ void __next_mem_range(u64 *idx, int nid, enum memblock_flags flags,
 	int idx_a = *idx & 0xffffffff;
 	int idx_b = *idx >> 32;
 
-	if (WARN_ONCE(nid == MAX_NUMNODES,
-	"Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
-		nid = NUMA_NO_NODE;
-
 	for (; idx_a < type_a->cnt; idx_a++) {
 		struct memblock_region *m = &type_a->regions[idx_a];
 
@@ -1215,9 +1211,6 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid,
 	int idx_a = *idx & 0xffffffff;
 	int idx_b = *idx >> 32;
 
-	if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
-		nid = NUMA_NO_NODE;
-
 	if (*idx == (u64)ULLONG_MAX) {
 		idx_a = type_a->cnt - 1;
 		if (type_b != NULL)
@@ -1303,7 +1296,7 @@ void __init_memblock __next_mem_pfn_range(int *idx, int nid,
 
 		if (PFN_UP(r->base) >= PFN_DOWN(r->base + r->size))
 			continue;
-		if (nid == MAX_NUMNODES || nid == r_nid)
+		if (!numa_valid_node(nid) || nid == r_nid)
 			break;
 	}
 	if (*idx >= type->cnt) {
@@ -1339,10 +1332,6 @@ int __init_memblock memblock_set_node(phys_addr_t base, phys_addr_t size,
 	int start_rgn, end_rgn;
 	int i, ret;
 
-	if (WARN_ONCE(nid == MAX_NUMNODES,
-		      "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
-		nid = NUMA_NO_NODE;
-
 	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
 	if (ret)
 		return ret;
@@ -1452,9 +1441,6 @@ phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
 	enum memblock_flags flags = choose_memblock_flags();
 	phys_addr_t found;
 
-	if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
-		nid = NUMA_NO_NODE;
-
 	if (!align) {
 		/* Can't use WARNs this early in boot on powerpc */
 		dump_stack();
@@ -1467,7 +1453,7 @@ phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
 	if (found && !memblock_reserve(found, size))
 		goto done;
 
-	if (nid != NUMA_NO_NODE && !exact_nid) {
+	if (numa_valid_node(nid) && !exact_nid) {
 		found = memblock_find_in_range_node(size, align, start,
 						    end, NUMA_NO_NODE,
 						    flags);
@@ -1987,7 +1973,7 @@ static void __init_memblock memblock_dump(struct memblock_type *type)
 		end = base + size - 1;
 		flags = rgn->flags;
 #ifdef CONFIG_NUMA
-		if (memblock_get_region_node(rgn) != MAX_NUMNODES)
+		if (numa_valid_node(memblock_get_region_node(rgn)))
 			snprintf(nid_buf, sizeof(nid_buf), " on node %d",
 				 memblock_get_region_node(rgn));
 #endif
@@ -2181,7 +2167,7 @@ static void __init memmap_init_reserved_pages(void)
 			start = region->base;
 			end = start + region->size;
 
-			if (nid == NUMA_NO_NODE || nid >= MAX_NUMNODES)
+			if (!numa_valid_node(nid))
 				nid = early_pfn_to_nid(PFN_DOWN(start));
 
 			reserve_bootmem_region(start, end, nid);
@@ -2272,7 +2258,7 @@ static int memblock_debug_show(struct seq_file *m, void *private)
 
 		seq_printf(m, "%4d: ", i);
 		seq_printf(m, "%pa..%pa ", &reg->base, &end);
-		if (nid != MAX_NUMNODES)
+		if (numa_valid_node(nid))
 			seq_printf(m, "%4d ", nid);
 		else
 			seq_printf(m, "%4c ", 'x');
-- 
2.43.0

 
>               Linus

-- 
Sincerely yours,
Mike.




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