Introduce a new helper percpu_size() to report full size of underlying
allocation of a percpu address.
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
include/linux/percpu.h | 1 +
mm/percpu.c | 35 +++++++++++++++++++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 1338ea2..7be4234 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -137,5 +137,6 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size,
__alignof__(type))
extern unsigned long pcpu_nr_pages(void);
+extern size_t percpu_size(void __percpu *ptr);
#endif /* __LINUX_PERCPU_H */
diff --git a/mm/percpu.c b/mm/percpu.c
index acd78da..5580688 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -2302,6 +2302,41 @@ void free_percpu(void __percpu *ptr)
}
EXPORT_SYMBOL_GPL(free_percpu);
+/**
+ * percpu_size - report full size of underlying allocation of percpu addr
+ * @ptr: pointer to percpu area
+ *
+ * CONTEXT:
+ * Can be called from atomic context.
+ */
+size_t percpu_size(void __percpu *ptr)
+{
+ int bit_off, bits, end, off, size;
+ struct pcpu_chunk *chunk;
+ unsigned long flags;
+ void *addr;
+
+ if (!ptr)
+ return 0;
+
+ addr = __pcpu_ptr_to_addr(ptr);
+
+ spin_lock_irqsave(&pcpu_lock, flags);
+ chunk = pcpu_chunk_addr_search(addr);
+ off = addr - chunk->base_addr;
+ bit_off = off / PCPU_MIN_ALLOC_SIZE;
+
+ /* find end index */
+ end = find_next_bit(chunk->bound_map, pcpu_chunk_map_bits(chunk),
+ bit_off + 1);
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+
+ bits = end - bit_off;
+ size = bits * PCPU_MIN_ALLOC_SIZE;
+
+ return pcpu_obj_full_size(size);
+}
+
bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr)
{
#ifdef CONFIG_SMP
--
1.8.3.1
