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memblock: unpreserve memory in case of error 

If there is an error half way through KHO memory preservation, we should
rollback and unpreserve everything that is partially preserved.

[akpm@linux-foundation.org: s/err_no_fdt_page/err_report/ in prepare_kho_fdt(), per Mike]
Link: https://lkml.kernel.org/r/20251101142325.1326536-5-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Suggested-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
pull/1354/merge
Pasha Tatashin 2025-11-01 10:23:20 -04:00 committed by Andrew Morton
parent 36f8f7ef7f
commit f5bfd4793a
1 changed files with 67 additions and 24 deletions
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91
mm/memblock.c
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@ -2445,29 +2445,60 @@ int reserve_mem_release_by_name(const char *name)
#define MEMBLOCK_KHO_NODE_COMPATIBLE "memblock-v1"
#define RESERVE_MEM_KHO_NODE_COMPATIBLE "reserve-mem-v1"
static int __init prepare_kho_fdt(void)
static int __init reserved_mem_preserve(void)
{
int err = 0, i;
struct page *fdt_page;
void *fdt;
unsigned int nr_preserved = 0;
int err;
fdt_page = alloc_page(GFP_KERNEL);
if (!fdt_page)
return -ENOMEM;
fdt = page_to_virt(fdt_page);
err |= fdt_create(fdt, PAGE_SIZE);
err |= fdt_finish_reservemap(fdt);
err |= fdt_begin_node(fdt, "");
err |= fdt_property_string(fdt, "compatible", MEMBLOCK_KHO_NODE_COMPATIBLE);
for (i = 0; i < reserved_mem_count; i++) {
for (unsigned int i = 0; i < reserved_mem_count; i++, nr_preserved++) {
struct reserve_mem_table *map = &reserved_mem_table[i];
struct page *page = phys_to_page(map->start);
unsigned int nr_pages = map->size >> PAGE_SHIFT;
err |= kho_preserve_pages(page, nr_pages);
err = kho_preserve_pages(page, nr_pages);
if (err)
goto err_unpreserve;
}
return 0;
err_unpreserve:
for (unsigned int i = 0; i < nr_preserved; i++) {
struct reserve_mem_table *map = &reserved_mem_table[i];
struct page *page = phys_to_page(map->start);
unsigned int nr_pages = map->size >> PAGE_SHIFT;
kho_unpreserve_pages(page, nr_pages);
}
return err;
}
static int __init prepare_kho_fdt(void)
{
struct page *fdt_page;
void *fdt;
int err;
fdt_page = alloc_page(GFP_KERNEL);
if (!fdt_page) {
err = -ENOMEM;
goto err_report;
}
fdt = page_to_virt(fdt_page);
err = kho_preserve_pages(fdt_page, 1);
if (err)
goto err_free_fdt;
err |= fdt_create(fdt, PAGE_SIZE);
err |= fdt_finish_reservemap(fdt);
err |= fdt_begin_node(fdt, "");
err |= fdt_property_string(fdt, "compatible", MEMBLOCK_KHO_NODE_COMPATIBLE);
for (unsigned int i = 0; !err && i < reserved_mem_count; i++) {
struct reserve_mem_table *map = &reserved_mem_table[i];
err |= fdt_begin_node(fdt, map->name);
err |= fdt_property_string(fdt, "compatible", RESERVE_MEM_KHO_NODE_COMPATIBLE);
err |= fdt_property(fdt, "start", &map->start, sizeof(map->start));
@ -2477,15 +2508,27 @@ static int __init prepare_kho_fdt(void)
err |= fdt_end_node(fdt);
err |= fdt_finish(fdt);
err |= kho_preserve_folio(page_folio(fdt_page));
if (err)
goto err_unpreserve_fdt;
if (!err)
err = kho_add_subtree(MEMBLOCK_KHO_FDT, fdt);
err = kho_add_subtree(MEMBLOCK_KHO_FDT, fdt);
if (err)
goto err_unpreserve_fdt;
if (err) {
pr_err("failed to prepare memblock FDT for KHO: %d\n", err);
put_page(fdt_page);
}
err = reserved_mem_preserve();
if (err)
goto err_remove_subtree;
return 0;
err_remove_subtree:
kho_remove_subtree(fdt);
err_unpreserve_fdt:
kho_unpreserve_pages(fdt_page, 1);
err_free_fdt:
put_page(fdt_page);
err_report:
pr_err("failed to prepare memblock FDT for KHO: %d\n", err);
return err;
}