[PATCH 4.16 205/272] block: null_blk: fix Invalid parameters when loading module

Greg Kroah-Hartman
2018-05-28T11:13:28Z

From: Ming Lei <ming.lei@redhat.com>

[ Upstream commit 66231ad3e2886ba99fbf440cea44cab547e5163f ]

On ARM64, the default page size has been 64K on some distributions, and
we should allow ARM64 people to play null_blk.

This patch fixes the issue by extend page bitmap size for supporting
other non-4KB PAGE_SIZE.

Cc: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Kyungchan Koh <kkc6196@fb.com>,
Cc: weiping zhang <zhangweiping@didichuxing.com>
Cc: Yi Zhang <yi.zhang@redhat.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/block/null_blk.c | 46 +++++++++++++++++++++++++---------------------
1 file changed, 25 insertions(+), 21 deletions(-)

--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -72,6 +72,7 @@ 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.
*
@@ -86,10 +87,10 @@ 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;
@@ -728,7 +729,7 @@ static struct nullb_page *null_alloc_pag
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);
@@ -738,13 +739,20 @@ 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)
{
@@ -759,9 +767,9 @@ static void null_free_sector(struct null

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);
@@ -832,7 +840,7 @@ static struct nullb_page *__null_lookup_
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;
@@ -895,10 +903,10 @@ static int null_flush_cache_page(struct

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);
@@ -914,11 +922,11 @@ static int null_flush_cache_page(struct

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);
}
}

@@ -955,10 +963,10 @@ 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;
@@ -1011,7 +1019,7 @@ static int copy_to_nullb(struct nullb *n
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);
@@ -1802,10 +1810,6 @@ 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);