diff options
| -rw-r--r-- | include/linux/zsmalloc.h | 4 | ||||
| -rw-r--r-- | mm/zsmalloc.c | 63 |
2 files changed, 67 insertions, 0 deletions
diff --git a/include/linux/zsmalloc.h b/include/linux/zsmalloc.h index 5565c3171007..478410c880b1 100644 --- a/include/linux/zsmalloc.h +++ b/include/linux/zsmalloc.h @@ -22,6 +22,7 @@ struct zs_pool_stats { }; struct zs_pool; +struct scatterlist; struct zs_pool *zs_create_pool(const char *name); void zs_destroy_pool(struct zs_pool *pool); @@ -43,6 +44,9 @@ void *zs_obj_read_begin(struct zs_pool *pool, unsigned long handle, size_t mem_len, void *local_copy); void zs_obj_read_end(struct zs_pool *pool, unsigned long handle, size_t mem_len, void *handle_mem); +void zs_obj_read_sg_begin(struct zs_pool *pool, unsigned long handle, + struct scatterlist *sg, size_t mem_len); +void zs_obj_read_sg_end(struct zs_pool *pool, unsigned long handle); void zs_obj_write(struct zs_pool *pool, unsigned long handle, void *handle_mem, size_t mem_len); diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index cc3d9501ae21..dccb88d52c07 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -30,6 +30,7 @@ #include <linux/highmem.h> #include <linux/string.h> #include <linux/slab.h> +#include <linux/scatterlist.h> #include <linux/spinlock.h> #include <linux/sprintf.h> #include <linux/shrinker.h> @@ -1141,6 +1142,68 @@ void zs_obj_read_end(struct zs_pool *pool, unsigned long handle, } EXPORT_SYMBOL_GPL(zs_obj_read_end); +void zs_obj_read_sg_begin(struct zs_pool *pool, unsigned long handle, + struct scatterlist *sg, size_t mem_len) +{ + struct zspage *zspage; + struct zpdesc *zpdesc; + unsigned long obj, off; + unsigned int obj_idx; + struct size_class *class; + + /* Guarantee we can get zspage from handle safely */ + read_lock(&pool->lock); + obj = handle_to_obj(handle); + obj_to_location(obj, &zpdesc, &obj_idx); + zspage = get_zspage(zpdesc); + + /* Make sure migration doesn't move any pages in this zspage */ + zspage_read_lock(zspage); + read_unlock(&pool->lock); + + class = zspage_class(pool, zspage); + off = offset_in_page(class->size * obj_idx); + + if (!ZsHugePage(zspage)) + off += ZS_HANDLE_SIZE; + + if (off + mem_len <= PAGE_SIZE) { + /* this object is contained entirely within a page */ + sg_init_table(sg, 1); + sg_set_page(sg, zpdesc_page(zpdesc), mem_len, off); + } else { + size_t sizes[2]; + + /* this object spans two pages */ + sizes[0] = PAGE_SIZE - off; + sizes[1] = mem_len - sizes[0]; + + sg_init_table(sg, 2); + sg_set_page(sg, zpdesc_page(zpdesc), sizes[0], off); + + zpdesc = get_next_zpdesc(zpdesc); + sg = sg_next(sg); + + sg_set_page(sg, zpdesc_page(zpdesc), sizes[1], 0); + } +} +EXPORT_SYMBOL_GPL(zs_obj_read_sg_begin); + +void zs_obj_read_sg_end(struct zs_pool *pool, unsigned long handle) +{ + struct zspage *zspage; + struct zpdesc *zpdesc; + unsigned long obj; + unsigned int obj_idx; + + obj = handle_to_obj(handle); + obj_to_location(obj, &zpdesc, &obj_idx); + zspage = get_zspage(zpdesc); + + zspage_read_unlock(zspage); +} +EXPORT_SYMBOL_GPL(zs_obj_read_sg_end); + void zs_obj_write(struct zs_pool *pool, unsigned long handle, void *handle_mem, size_t mem_len) { |