diff options
| -rw-r--r-- | drivers/block/null_blk.c | 46 |
1 files changed, 25 insertions, 21 deletions
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index 6dc7e7cfca4a..d6be7a6d8ca6 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -74,6 +74,7 @@ enum nullb_device_flags { NULLB_DEV_FL_CACHE = 3, }; +#define MAP_SZ ((PAGE_SIZE >> SECTOR_SHIFT) + 2) /* * nullb_page is a page in memory for nullb devices. * @@ -88,10 +89,10 @@ enum nullb_device_flags { */ struct nullb_page { struct page *page; - unsigned long bitmap; + DECLARE_BITMAP(bitmap, MAP_SZ); }; -#define NULLB_PAGE_LOCK (sizeof(unsigned long) * 8 - 1) -#define NULLB_PAGE_FREE (sizeof(unsigned long) * 8 - 2) +#define NULLB_PAGE_LOCK (MAP_SZ - 1) +#define NULLB_PAGE_FREE (MAP_SZ - 2) struct nullb_device { struct nullb *nullb; @@ -733,7 +734,7 @@ static struct nullb_page *null_alloc_page(gfp_t gfp_flags) if (!t_page->page) goto out_freepage; - t_page->bitmap = 0; + memset(t_page->bitmap, 0, sizeof(t_page->bitmap)); return t_page; out_freepage: kfree(t_page); @@ -743,13 +744,20 @@ out: static void null_free_page(struct nullb_page *t_page) { - __set_bit(NULLB_PAGE_FREE, &t_page->bitmap); - if (test_bit(NULLB_PAGE_LOCK, &t_page->bitmap)) + __set_bit(NULLB_PAGE_FREE, t_page->bitmap); + if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap)) return; __free_page(t_page->page); kfree(t_page); } +static bool null_page_empty(struct nullb_page *page) +{ + int size = MAP_SZ - 2; + + return find_first_bit(page->bitmap, size) == size; +} + static void null_free_sector(struct nullb *nullb, sector_t sector, bool is_cache) { @@ -764,9 +772,9 @@ static void null_free_sector(struct nullb *nullb, sector_t sector, t_page = radix_tree_lookup(root, idx); if (t_page) { - __clear_bit(sector_bit, &t_page->bitmap); + __clear_bit(sector_bit, t_page->bitmap); - if (!t_page->bitmap) { + if (null_page_empty(t_page)) { ret = radix_tree_delete_item(root, idx, t_page); WARN_ON(ret != t_page); null_free_page(ret); @@ -837,7 +845,7 @@ static struct nullb_page *__null_lookup_page(struct nullb *nullb, t_page = radix_tree_lookup(root, idx); WARN_ON(t_page && t_page->page->index != idx); - if (t_page && (for_write || test_bit(sector_bit, &t_page->bitmap))) + if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap))) return t_page; return NULL; @@ -900,10 +908,10 @@ static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page) t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true); - __clear_bit(NULLB_PAGE_LOCK, &c_page->bitmap); - if (test_bit(NULLB_PAGE_FREE, &c_page->bitmap)) { + __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap); + if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) { null_free_page(c_page); - if (t_page && t_page->bitmap == 0) { + if (t_page && null_page_empty(t_page)) { ret = radix_tree_delete_item(&nullb->dev->data, idx, t_page); null_free_page(t_page); @@ -919,11 +927,11 @@ static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page) for (i = 0; i < PAGE_SECTORS; i += (nullb->dev->blocksize >> SECTOR_SHIFT)) { - if (test_bit(i, &c_page->bitmap)) { + if (test_bit(i, c_page->bitmap)) { offset = (i << SECTOR_SHIFT); memcpy(dst + offset, src + offset, nullb->dev->blocksize); - __set_bit(i, &t_page->bitmap); + __set_bit(i, t_page->bitmap); } } @@ -960,10 +968,10 @@ again: * We found the page which is being flushed to disk by other * threads */ - if (test_bit(NULLB_PAGE_LOCK, &c_pages[i]->bitmap)) + if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap)) c_pages[i] = NULL; else - __set_bit(NULLB_PAGE_LOCK, &c_pages[i]->bitmap); + __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap); } one_round = 0; @@ -1016,7 +1024,7 @@ static int copy_to_nullb(struct nullb *nullb, struct page *source, kunmap_atomic(dst); kunmap_atomic(src); - __set_bit(sector & SECTOR_MASK, &t_page->bitmap); + __set_bit(sector & SECTOR_MASK, t_page->bitmap); if (is_fua) null_free_sector(nullb, sector, true); @@ -1846,10 +1854,6 @@ static int __init null_init(void) struct nullb *nullb; struct nullb_device *dev; - /* check for nullb_page.bitmap */ - if (sizeof(unsigned long) * 8 - 2 < (PAGE_SIZE >> SECTOR_SHIFT)) - return -EINVAL; - if (g_bs > PAGE_SIZE) { pr_warn("null_blk: invalid block size\n"); pr_warn("null_blk: defaults block size to %lu\n", PAGE_SIZE); |