On 3/15/24 19:12, Matthew Wilcox (Oracle) wrote:
This debugging check will become more costly in the future when we shrink
struct page. It has not proven to be useful, so simply remove it.
This lets us use __xa_insert instead of __xa_cmpxchg() as we no longer
need to know about the page that is currently stored in the XArray.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
drivers/block/brd.c | 40 +++++++++++-----------------------------
1 file changed, 11 insertions(+), 29 deletions(-)
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index e322cef6596b..b900fe9e0030 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -29,10 +29,7 @@
/*
* Each block ramdisk device has a xarray brd_pages of pages that stores
- * the pages containing the block device's contents. A brd page's ->index is
- * its offset in PAGE_SIZE units. This is similar to, but in no way connected
- * with, the kernel's pagecache or buffer cache (which sit above our block
- * device).
+ * the pages containing the block device's contents.
*/
struct brd_device {
int brd_number;
@@ -51,15 +48,7 @@ struct brd_device {
*/
static struct page *brd_lookup_page(struct brd_device *brd, sector_t sector)
{
- pgoff_t idx;
- struct page *page;
-
- idx = sector >> PAGE_SECTORS_SHIFT; /* sector to page index */
- page = xa_load(&brd->brd_pages, idx);
-
- BUG_ON(page && page->index != idx);
-
- return page;
+ return xa_load(&brd->brd_pages, sector >> PAGE_SECTORS_SHIFT);
}
/*
@@ -67,8 +56,8 @@ static struct page *brd_lookup_page(struct brd_device *brd, sector_t sector)
*/
static int brd_insert_page(struct brd_device *brd, sector_t sector, gfp_t gfp)
{
- pgoff_t idx;
- struct page *page, *cur;
+ pgoff_t idx = sector >> PAGE_SECTORS_SHIFT;
+ struct page *page;
int ret = 0;
page = brd_lookup_page(brd, sector);
@@ -80,23 +69,16 @@ static int brd_insert_page(struct brd_device *brd, sector_t sector, gfp_t gfp)
return -ENOMEM;
xa_lock(&brd->brd_pages);
-
- idx = sector >> PAGE_SECTORS_SHIFT;
- page->index = idx;
-
- cur = __xa_cmpxchg(&brd->brd_pages, idx, NULL, page, gfp);
-
- if (unlikely(cur)) {
- __free_page(page);
- ret = xa_err(cur);
- if (!ret && (cur->index != idx))
- ret = -EIO;
- } else {
+ ret = __xa_insert(&brd->brd_pages, idx, page, gfp);
+ if (!ret)
brd->brd_nr_pages++;
- }
-
xa_unlock(&brd->brd_pages);
+ if (ret < 0) {
+ __free_page(page);
+ if (ret == -EBUSY)
+ ret = 0;
+ }
return ret;
}
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
