diff options
Diffstat (limited to 'drivers/block/brd.c')
| -rw-r--r-- | drivers/block/brd.c | 66 |
1 files changed, 37 insertions, 29 deletions
diff --git a/drivers/block/brd.c b/drivers/block/brd.c index e322cef6596b..558d8e670566 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; } @@ -240,6 +222,23 @@ out: return err; } +static void brd_do_discard(struct brd_device *brd, sector_t sector, u32 size) +{ + sector_t aligned_sector = (sector + PAGE_SECTORS) & ~PAGE_SECTORS; + struct page *page; + + size -= (aligned_sector - sector) * SECTOR_SIZE; + xa_lock(&brd->brd_pages); + while (size >= PAGE_SIZE && aligned_sector < rd_size * 2) { + page = __xa_erase(&brd->brd_pages, aligned_sector >> PAGE_SECTORS_SHIFT); + if (page) + __free_page(page); + aligned_sector += PAGE_SECTORS; + size -= PAGE_SIZE; + } + xa_unlock(&brd->brd_pages); +} + static void brd_submit_bio(struct bio *bio) { struct brd_device *brd = bio->bi_bdev->bd_disk->private_data; @@ -247,6 +246,12 @@ static void brd_submit_bio(struct bio *bio) struct bio_vec bvec; struct bvec_iter iter; + if (unlikely(op_is_discard(bio->bi_opf))) { + brd_do_discard(brd, sector, bio->bi_iter.bi_size); + bio_endio(bio); + return; + } + bio_for_each_segment(bvec, bio, iter) { unsigned int len = bvec.bv_len; int err; @@ -327,6 +332,9 @@ static int brd_alloc(int i) * is harmless) */ .physical_block_size = PAGE_SIZE, + .max_hw_discard_sectors = UINT_MAX, + .max_discard_segments = 1, + .discard_granularity = PAGE_SIZE, }; list_for_each_entry(brd, &brd_devices, brd_list) |