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Subject[PATCH 3/4] memblock: extend memblock_cap_memory_range to multiple ranges
Date
From: Mike Rapoport <rppt@linux.ibm.com>

The memblock_cap_memory_range() removes all the memory except the
range passed to it. Extend this function to receive an array of
memblock_regions that should be kept. This allows switching to
simple iteration over memblock arrays with 'for_each_mem_range_rev'
to remove the unneeded memory.

Enable use of this function in arm64 for reservation of multiple
regions for the crash kernel.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
arch/arm64/mm/init.c | 38 ++++++++++++++++++++++++++++----------
include/linux/memblock.h | 2 +-
mm/memblock.c | 44 ++++++++++++++++++++------------------------
3 files changed, 49 insertions(+), 35 deletions(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 3fcd739..2d8f302 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -63,6 +63,13 @@ EXPORT_SYMBOL(memstart_addr);

phys_addr_t arm64_dma_phys_limit __ro_after_init;

+/* The main usage of linux,usable-memory-range is for crash dump kernel.
+ * Originally, the number of usable-memory regions is one. Now crash dump
+ * kernel support at most two crash kernel regions, low_region and high
+ * region.
+ */
+#define MAX_USABLE_RANGES 2
+
#ifdef CONFIG_KEXEC_CORE
/*
* reserve_crashkernel() - reserves memory for crash kernel
@@ -302,9 +309,9 @@ early_param("mem", early_mem);
static int __init early_init_dt_scan_usablemem(unsigned long node,
const char *uname, int depth, void *data)
{
- struct memblock_region *usablemem = data;
- const __be32 *reg;
- int len;
+ struct memblock_type *usablemem = data;
+ const __be32 *reg, *endp;
+ int len, nr = 0;

if (depth != 1 || strcmp(uname, "chosen") != 0)
return 0;
@@ -313,22 +320,33 @@ static int __init early_init_dt_scan_usablemem(unsigned long node,
if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells)))
return 1;

- usablemem->base = dt_mem_next_cell(dt_root_addr_cells, &reg);
- usablemem->size = dt_mem_next_cell(dt_root_size_cells, &reg);
+ endp = reg + (len / sizeof(__be32));
+ while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
+ unsigned long base = dt_mem_next_cell(dt_root_addr_cells, &reg);
+ unsigned long size = dt_mem_next_cell(dt_root_size_cells, &reg);
+
+ if (memblock_add_range(usablemem, base, size, NUMA_NO_NODE,
+ MEMBLOCK_NONE))
+ return 0;
+ if (++nr >= MAX_USABLE_RANGES)
+ break;
+ }

return 1;
}

static void __init fdt_enforce_memory_region(void)
{
- struct memblock_region reg = {
- .size = 0,
+ struct memblock_region usable_regions[MAX_USABLE_RANGES];
+ struct memblock_type usablemem = {
+ .max = MAX_USABLE_RANGES,
+ .regions = usable_regions,
};

- of_scan_flat_dt(early_init_dt_scan_usablemem, &reg);
+ of_scan_flat_dt(early_init_dt_scan_usablemem, &usablemem);

- if (reg.size)
- memblock_cap_memory_range(reg.base, reg.size);
+ if (usablemem.cnt)
+ memblock_cap_memory_ranges(usablemem.regions, usablemem.cnt);
}

void __init arm64_memblock_init(void)
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 676d390..526e279 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -446,7 +446,7 @@ phys_addr_t memblock_mem_size(unsigned long limit_pfn);
phys_addr_t memblock_start_of_DRAM(void);
phys_addr_t memblock_end_of_DRAM(void);
void memblock_enforce_memory_limit(phys_addr_t memory_limit);
-void memblock_cap_memory_range(phys_addr_t base, phys_addr_t size);
+void memblock_cap_memory_ranges(struct memblock_region *regions, int count);
void memblock_mem_limit_remove_map(phys_addr_t limit);
bool memblock_is_memory(phys_addr_t addr);
bool memblock_is_map_memory(phys_addr_t addr);
diff --git a/mm/memblock.c b/mm/memblock.c
index 6bbad46..ecdf8a9 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1669,36 +1669,31 @@ void __init memblock_enforce_memory_limit(phys_addr_t limit)
PHYS_ADDR_MAX);
}

-void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
-{
- int start_rgn, end_rgn;
- int i, ret;
-
- if (!size)
- return;
-
- ret = memblock_isolate_range(&memblock.memory, base, size,
- &start_rgn, &end_rgn);
- if (ret)
- return;
-
- /* remove all the MAP regions */
- for (i = memblock.memory.cnt - 1; i >= end_rgn; i--)
- if (!memblock_is_nomap(&memblock.memory.regions[i]))
- memblock_remove_region(&memblock.memory, i);
+void __init memblock_cap_memory_ranges(struct memblock_region *regions,
+ int count)
+{
+ struct memblock_type regions_to_keep = {
+ .max = count,
+ .cnt = count,
+ .regions = regions,
+ };
+ phys_addr_t start, end;
+ u64 i;

- for (i = start_rgn - 1; i >= 0; i--)
- if (!memblock_is_nomap(&memblock.memory.regions[i]))
- memblock_remove_region(&memblock.memory, i);
+ /* truncate memory while skipping NOMAP regions */
+ for_each_mem_range_rev(i, &memblock.memory, &regions_to_keep,
+ NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL)
+ memblock_remove(start, end - start);

/* truncate the reserved regions */
- memblock_remove_range(&memblock.reserved, 0, base);
- memblock_remove_range(&memblock.reserved,
- base + size, PHYS_ADDR_MAX);
+ for_each_mem_range_rev(i, &memblock.reserved, &regions_to_keep,
+ NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL)
+ memblock_remove_range(&memblock.reserved, start, end - start);
}

void __init memblock_mem_limit_remove_map(phys_addr_t limit)
{
+ struct memblock_region region = { 0 };
phys_addr_t max_addr;

if (!limit)
@@ -1710,7 +1705,8 @@ void __init memblock_mem_limit_remove_map(phys_addr_t limit)
if (max_addr == PHYS_ADDR_MAX)
return;

- memblock_cap_memory_range(0, max_addr);
+ region.size = max_addr;
+ memblock_cap_memory_ranges(&region, 1);
}

static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr)
--
2.7.4
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