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brd: Remove use of page->index

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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@infradead.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20240315181212.2573753-1-willy@infradead.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Matthew Wilcox (Oracle) 2024-03-15 18:12:09 +00:00 committed by Jens Axboe
parent 39cd87c4eb
commit 7d8d35791b
1 changed files with 11 additions and 29 deletions
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40
drivers/block/brd.c
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@ -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;
}