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drivers/base/memory: make memory block get/put explicit

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Rename the memory block lookup helper to make the acquired reference
explicit, add memory_block_put() to wrap put_device(), remove
find_memory_block(), and use memory_block_get() as the single block-id
based lookup interface.

This makes it clearer to callers that a successful lookup holds a
reference that must be dropped, reducing the chance of forgetting the
matching put and leaking the memory block device reference.

Link: https://lore.kernel.org/linux-mm/7887915D-E598-42B3-9AFE-BFFBACE8DE2D@linux.dev/#t
Link: https://lore.kernel.org/20260512072635.3969576-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Tested-by: Sumanth Korikkar <sumanthk@linux.ibm.com> #s390
Cc: Richard Cheng <icheng@nvidia.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Muchun Song
2026-05-12 15:26:35 +08:00
committed by Andrew Morton
parent 6d544529f9
commit 9b1b295e9f
6 changed files with 35 additions and 50 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
arch/powerpc/platforms/pseries/hotplug-memory.c
View File

@@ -164,13 +164,7 @@ static int update_lmb_associativity_index(struct drmem_lmb *lmb)
static struct memory_block *lmb_to_memblock(struct drmem_lmb *lmb)
{
unsigned long section_nr;
struct memory_block *mem_block;
section_nr = pfn_to_section_nr(PFN_DOWN(lmb->base_addr));
mem_block = find_memory_block(section_nr);
return mem_block;
return memory_block_get(phys_to_block_id(lmb->base_addr));
}
static int get_lmb_range(u32 drc_index, int n_lmbs,
@@ -220,7 +214,7 @@ static int dlpar_change_lmb_state(struct drmem_lmb *lmb, bool online)
else
rc = 0;
put_device(&mem_block->dev);
memory_block_put(mem_block);
return rc;
}
@@ -319,12 +313,12 @@ static int dlpar_remove_lmb(struct drmem_lmb *lmb)
rc = dlpar_offline_lmb(lmb);
if (rc) {
put_device(&mem_block->dev);
memory_block_put(mem_block);
return rc;
}
__remove_memory(lmb->base_addr, memory_block_size);
put_device(&mem_block->dev);
memory_block_put(mem_block);
/* Update memory regions for memory remove */
memblock_remove(lmb->base_addr, memory_block_size);

38
drivers/base/memory.c
View File

@@ -649,7 +649,7 @@ int __weak arch_get_memory_phys_device(unsigned long start_pfn)
*
* Called under device_hotplug_lock.
*/
struct memory_block *find_memory_block_by_id(unsigned long block_id)
struct memory_block *memory_block_get(unsigned long block_id)
{
struct memory_block *mem;
@@ -659,16 +659,6 @@ struct memory_block *find_memory_block_by_id(unsigned long block_id)
return mem;
}
/*
* Called under device_hotplug_lock.
*/
struct memory_block *find_memory_block(unsigned long section_nr)
{
unsigned long block_id = memory_block_id(section_nr);
return find_memory_block_by_id(block_id);
}
static struct attribute *memory_memblk_attrs[] = {
&dev_attr_phys_index.attr,
&dev_attr_state.attr,
@@ -701,7 +691,7 @@ static int __add_memory_block(struct memory_block *memory)
ret = device_register(&memory->dev);
if (ret) {
put_device(&memory->dev);
memory_block_put(memory);
return ret;
}
ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
@@ -795,9 +785,9 @@ static int add_memory_block(unsigned long block_id, int nid, unsigned long state
struct memory_block *mem;
int ret = 0;
mem = find_memory_block_by_id(block_id);
mem = memory_block_get(block_id);
if (mem) {
put_device(&mem->dev);
memory_block_put(mem);
return -EEXIST;
}
mem = kzalloc_obj(*mem);
@@ -845,8 +835,8 @@ static void remove_memory_block(struct memory_block *memory)
memory->group = NULL;
}
/* drop the ref. we got via find_memory_block() */
put_device(&memory->dev);
/* drop the ref. we got via memory_block_get() */
memory_block_put(memory);
device_unregister(&memory->dev);
}
@@ -880,7 +870,7 @@ int create_memory_block_devices(unsigned long start, unsigned long size,
end_block_id = block_id;
for (block_id = start_block_id; block_id != end_block_id;
block_id++) {
mem = find_memory_block_by_id(block_id);
mem = memory_block_get(block_id);
if (WARN_ON_ONCE(!mem))
continue;
remove_memory_block(mem);
@@ -908,7 +898,7 @@ void remove_memory_block_devices(unsigned long start, unsigned long size)
return;
for (block_id = start_block_id; block_id != end_block_id; block_id++) {
mem = find_memory_block_by_id(block_id);
mem = memory_block_get(block_id);
if (WARN_ON_ONCE(!mem))
continue;
num_poisoned_pages_sub(-1UL, memblk_nr_poison(mem));
@@ -1015,12 +1005,12 @@ int walk_memory_blocks(unsigned long start, unsigned long size,
return 0;
for (block_id = start_block_id; block_id <= end_block_id; block_id++) {
mem = find_memory_block_by_id(block_id);
mem = memory_block_get(block_id);
if (!mem)
continue;
ret = func(mem, arg);
put_device(&mem->dev);
memory_block_put(mem);
if (ret)
break;
}
@@ -1228,22 +1218,22 @@ int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
void memblk_nr_poison_inc(unsigned long pfn)
{
const unsigned long block_id = pfn_to_block_id(pfn);
struct memory_block *mem = find_memory_block_by_id(block_id);
struct memory_block *mem = memory_block_get(block_id);
if (mem) {
atomic_long_inc(&mem->nr_hwpoison);
put_device(&mem->dev);
memory_block_put(mem);
}
}
void memblk_nr_poison_sub(unsigned long pfn, long i)
{
const unsigned long block_id = pfn_to_block_id(pfn);
struct memory_block *mem = find_memory_block_by_id(block_id);
struct memory_block *mem = memory_block_get(block_id);
if (mem) {
atomic_long_sub(i, &mem->nr_hwpoison);
put_device(&mem->dev);
memory_block_put(mem);
}
}

4
drivers/base/node.c
View File

@@ -849,13 +849,13 @@ static void register_memory_blocks_under_nodes(void)
for (block_id = start_block_id; block_id <= end_block_id; block_id++) {
struct memory_block *mem;
mem = find_memory_block_by_id(block_id);
mem = memory_block_get(block_id);
if (!mem)
continue;
memory_block_add_nid_early(mem, nid);
do_register_memory_block_under_node(nid, mem);
put_device(&mem->dev);
memory_block_put(mem);
}
}

17
drivers/s390/char/sclp_mem.c
View File

@@ -204,7 +204,7 @@ static ssize_t sclp_config_mem_store(struct kobject *kobj, struct kobj_attribute
addr = sclp_mem->id * block_size;
/*
* Hold device_hotplug_lock when adding/removing memory blocks.
* Additionally, also protect calls to find_memory_block() and
* Additionally, also protect calls to memory_block_get() and
* sclp_attach_storage().
*/
rc = lock_device_hotplug_sysfs();
@@ -231,20 +231,19 @@ static ssize_t sclp_config_mem_store(struct kobject *kobj, struct kobj_attribute
sclp_mem_change_state(addr, block_size, 0);
goto out_unlock;
}
mem = find_memory_block(pfn_to_section_nr(PFN_DOWN(addr)));
put_device(&mem->dev);
mem = memory_block_get(phys_to_block_id(addr));
memory_block_put(mem);
WRITE_ONCE(sclp_mem->config, 1);
} else {
if (!sclp_mem->config)
goto out_unlock;
mem = find_memory_block(pfn_to_section_nr(PFN_DOWN(addr)));
mem = memory_block_get(phys_to_block_id(addr));
if (mem->state != MEM_OFFLINE) {
put_device(&mem->dev);
memory_block_put(mem);
rc = -EBUSY;
goto out_unlock;
}
/* drop the ref just got via find_memory_block() */
put_device(&mem->dev);
memory_block_put(mem);
sclp_mem_change_state(addr, block_size, 0);
__remove_memory(addr, block_size);
#ifdef CONFIG_KASAN
@@ -294,11 +293,11 @@ static ssize_t sclp_memmap_on_memory_store(struct kobject *kobj, struct kobj_att
return rc;
block_size = memory_block_size_bytes();
sclp_mem = container_of(kobj, struct sclp_mem, kobj);
mem = find_memory_block(pfn_to_section_nr(PFN_DOWN(sclp_mem->id * block_size)));
mem = memory_block_get(phys_to_block_id(sclp_mem->id * block_size));
if (!mem) {
WRITE_ONCE(sclp_mem->memmap_on_memory, value);
} else {
put_device(&mem->dev);
memory_block_put(mem);
rc = -EBUSY;
}
unlock_device_hotplug();

7
include/linux/memory.h
View File

@@ -158,7 +158,11 @@ int create_memory_block_devices(unsigned long start, unsigned long size,
void remove_memory_block_devices(unsigned long start, unsigned long size);
extern void memory_dev_init(void);
extern int memory_notify(enum memory_block_state state, void *v);
extern struct memory_block *find_memory_block(unsigned long section_nr);
struct memory_block *memory_block_get(unsigned long block_id);
static inline void memory_block_put(struct memory_block *mem)
{
put_device(&mem->dev);
}
typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
extern int walk_memory_blocks(unsigned long start, unsigned long size,
void *arg, walk_memory_blocks_func_t func);
@@ -171,7 +175,6 @@ struct memory_group *memory_group_find_by_id(int mgid);
typedef int (*walk_memory_groups_func_t)(struct memory_group *, void *);
int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
struct memory_group *excluded, void *arg);
struct memory_block *find_memory_block_by_id(unsigned long block_id);
#define hotplug_memory_notifier(fn, pri) ({ \
static __meminitdata struct notifier_block fn##_mem_nb =\
{ .notifier_call = fn, .priority = pri };\

5
mm/memory_hotplug.c
View File

@@ -1423,14 +1423,13 @@ static void remove_memory_blocks_and_altmaps(u64 start, u64 size)
struct vmem_altmap *altmap = NULL;
struct memory_block *mem;
mem = find_memory_block(pfn_to_section_nr(PFN_DOWN(cur_start)));
mem = memory_block_get(phys_to_block_id(cur_start));
if (WARN_ON_ONCE(!mem))
continue;
altmap = mem->altmap;
mem->altmap = NULL;
/* drop the ref. we got via find_memory_block() */
put_device(&mem->dev);
memory_block_put(mem);
remove_memory_block_devices(cur_start, memblock_size);
arch_remove_memory(cur_start, memblock_size, altmap, NULL);