memblock: implement for_each_reserved_mem_region() using __next_mem_region()

Iteration over memblock.reserved with for_each_reserved_mem_region() used
__next_reserved_mem_region() that implemented a subset of
__next_mem_region().

Use __for_each_mem_range() and, essentially, __next_mem_region() with
appropriate parameters to reduce code duplication.

While on it, rename for_each_reserved_mem_region() to
for_each_reserved_mem_range() for consistency.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>	[.clang-format]
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-17-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 20 insertions, 36 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index 4de76cf48434..a09cc4f057f0 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -132,6 +132,14 @@ struct memblock_type physmem = {
 };
 #endif
 
+/*
+ * keep a pointer to &memblock.memory in the text section to use it in
+ * __next_mem_range() and its helpers.
+ *  For architectures that do not keep memblock data after init, this
+ * pointer will be reset to NULL at memblock_discard()
+ */
+static __refdata struct memblock_type *memblock_memory = &memblock.memory;
+
 #define for_each_memblock_type(i, memblock_type, rgn)			\
 	for (i = 0, rgn = &memblock_type->regions[0];			\
 	     i < memblock_type->cnt;					\
@@ -402,6 +410,8 @@ void __init memblock_discard(void)
 				  memblock.memory.max);
 		__memblock_free_late(addr, size);
 	}
+
+	memblock_memory = NULL;
 }
 #endif
 
@@ -952,42 +962,16 @@ int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size)
 	return memblock_setclr_flag(base, size, 0, MEMBLOCK_NOMAP);
 }
 
-/**
- * __next_reserved_mem_region - next function for for_each_reserved_region()
- * @idx: pointer to u64 loop variable
- * @out_start: ptr to phys_addr_t for start address of the region, can be %NULL
- * @out_end: ptr to phys_addr_t for end address of the region, can be %NULL
- *
- * Iterate over all reserved memory regions.
- */
-void __init_memblock __next_reserved_mem_region(u64 *idx,
-					   phys_addr_t *out_start,
-					   phys_addr_t *out_end)
-{
-	struct memblock_type *type = &memblock.reserved;
-
-	if (*idx < type->cnt) {
-		struct memblock_region *r = &type->regions[*idx];
-		phys_addr_t base = r->base;
-		phys_addr_t size = r->size;
-
-		if (out_start)
-			*out_start = base;
-		if (out_end)
-			*out_end = base + size - 1;
-
-		*idx += 1;
-		return;
-	}
-
-	/* signal end of iteration */
-	*idx = ULLONG_MAX;
-}
-
-static bool should_skip_region(struct memblock_region *m, int nid, int flags)
+static bool should_skip_region(struct memblock_type *type,
+			       struct memblock_region *m,
+			       int nid, int flags)
 {
 	int m_nid = memblock_get_region_node(m);
 
+	/* we never skip regions when iterating memblock.reserved or physmem */
+	if (type != memblock_memory)
+		return false;
+
 	/* only memory regions are associated with nodes, check it */
 	if (nid != NUMA_NO_NODE && nid != m_nid)
 		return true;
@@ -1052,7 +1036,7 @@ void __next_mem_range(u64 *idx, int nid, enum memblock_flags flags,
 		phys_addr_t m_end = m->base + m->size;
 		int	    m_nid = memblock_get_region_node(m);
 
-		if (should_skip_region(m, nid, flags))
+		if (should_skip_region(type_a, m, nid, flags))
 			continue;
 
 		if (!type_b) {
@@ -1156,7 +1140,7 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid,
 		phys_addr_t m_end = m->base + m->size;
 		int m_nid = memblock_get_region_node(m);
 
-		if (should_skip_region(m, nid, flags))
+		if (should_skip_region(type_a, m, nid, flags))
 			continue;
 
 		if (!type_b) {
@@ -1981,7 +1965,7 @@ static unsigned long __init free_low_memory_core_early(void)
 
 	memblock_clear_hotplug(0, -1);
 
-	for_each_reserved_mem_region(i, &start, &end)
+	for_each_reserved_mem_range(i, &start, &end)
 		reserve_bootmem_region(start, end);
 
 	/*