/**
* pcpu_populate_chunk - populate and map an area of a pcpu_chunk
* @chunk: chunk of interest
* @off: offset to the area to populate
* @size: size of the area to populate in bytes
*
* For each cpu, populate and map pages [@page_start,@page_end) into
* @chunk. The area is cleared on return.
*
* CONTEXT:
* pcpu_alloc_mutex, does GFP_KERNEL allocation.
*/
static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
{
int page_start = PFN_DOWN(off);
int page_end = PFN_UP(off + size);
int free_end = page_start, unmap_end = page_start;
struct page **pages;
unsigned long *populated;
unsigned int cpu;
int rs, re, rc;
/* quick path, check whether all pages are already there */
rs = page_start;
pcpu_next_pop(chunk, &rs, &re, page_end);
if (rs == page_start && re == page_end)
goto clear;
/* need to allocate and map pages, this chunk can't be immutable */
WARN_ON(chunk->immutable);
pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
if (!pages)
return -ENOMEM;
/* alloc and map */
pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
if (rc)
goto err_free;
free_end = re;
}
static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
{
int page_start = PFN_DOWN(off);
int page_end = PFN_UP(off + size);
int free_end = page_start, unmap_end = page_start;
struct page **pages;
unsigned long *populated;
unsigned int cpu;
int rs, re, rc;
rs = page_start;
pcpu_next_pop(chunk, &rs, &re, page_end);
if (rs == page_start && re == page_end)
goto clear;
WARN_ON(chunk->immutable);
pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
if (!pages)
return -ENOMEM;
pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
if (rc)
goto err_free;
free_end = re;
}
/*! 2016-03-19 study -ing */
static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
{
int page_start = PFN_DOWN(off);
int page_end = PFN_UP(off + size);
int free_end = page_start, unmap_end = page_start;
struct page **pages;
unsigned long *populated;
unsigned int cpu;
int rs, re, rc;
/* quick path, check whether all pages are already there */
rs = page_start;
pcpu_next_pop(chunk, &rs, &re, page_end);
/*! populate 하려는 page_start, end 와 populated 의 rs, re 가 일치하면
* 더 할일 없이 goto clear.
*/
if (rs == page_start && re == page_end)
goto clear;
/* need to allocate and map pages, this chunk can't be immutable */
WARN_ON(chunk->immutable);
pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
if (!pages)
return -ENOMEM;
/* alloc and map */
/*! rs: region start, re: region end (Page Frame number 단위)
* page_start ~ page_end 까지 pcpu_next_unpop하며 loop 수행
*/
pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
/*! 한번이라도 alloc 실패 시 go to err_free. */
if (rc)
goto err_free;
free_end = re;
}
