From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: [PATCH 16/23] brd: remove discard support Date: Thu, 23 Mar 2017 10:33:34 -0400 Message-ID: <20170323143341.31549-17-hch@lst.de> References: <20170323143341.31549-1-hch@lst.de> Return-path: In-Reply-To: <20170323143341.31549-1-hch@lst.de> Sender: linux-scsi-owner@vger.kernel.org To: axboe@kernel.dk, martin.petersen@oracle.com, agk@redhat.com, snitzer@redhat.com, shli@kernel.org, philipp.reisner@linbit.com, lars.ellenberg@linbit.com Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, drbd-dev@lists.linbit.com, dm-devel@redhat.com, linux-raid@vger.kernel.org List-Id: linux-raid.ids It's just a in-driver reimplementation of writing zeroes to the pages, which fails if the discards aren't page aligned. Signed-off-by: Christoph Hellwig --- drivers/block/brd.c | 56 ----------------------------------------------------- 1 file changed, 56 deletions(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 3adc32a3153b..c15d0581531f 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -134,28 +134,6 @@ static struct page *brd_insert_page(struct brd_device *brd, sector_t sector) return page; } -static void brd_free_page(struct brd_device *brd, sector_t sector) -{ - struct page *page; - pgoff_t idx; - - spin_lock(&brd->brd_lock); - idx = sector >> PAGE_SECTORS_SHIFT; - page = radix_tree_delete(&brd->brd_pages, idx); - spin_unlock(&brd->brd_lock); - if (page) - __free_page(page); -} - -static void brd_zero_page(struct brd_device *brd, sector_t sector) -{ - struct page *page; - - page = brd_lookup_page(brd, sector); - if (page) - clear_highpage(page); -} - /* * Free all backing store pages and radix tree. This must only be called when * there are no other users of the device. @@ -212,24 +190,6 @@ static int copy_to_brd_setup(struct brd_device *brd, sector_t sector, size_t n) return 0; } -static void discard_from_brd(struct brd_device *brd, - sector_t sector, size_t n) -{ - while (n >= PAGE_SIZE) { - /* - * Don't want to actually discard pages here because - * re-allocating the pages can result in writeback - * deadlocks under heavy load. - */ - if (0) - brd_free_page(brd, sector); - else - brd_zero_page(brd, sector); - sector += PAGE_SIZE >> SECTOR_SHIFT; - n -= PAGE_SIZE; - } -} - /* * Copy n bytes from src to the brd starting at sector. Does not sleep. */ @@ -338,14 +298,6 @@ static blk_qc_t brd_make_request(struct request_queue *q, struct bio *bio) if (bio_end_sector(bio) > get_capacity(bdev->bd_disk)) goto io_error; - if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) { - if (sector & ((PAGE_SIZE >> SECTOR_SHIFT) - 1) || - bio->bi_iter.bi_size & ~PAGE_MASK) - goto io_error; - discard_from_brd(brd, sector, bio->bi_iter.bi_size); - goto out; - } - bio_for_each_segment(bvec, bio, iter) { unsigned int len = bvec.bv_len; int err; @@ -357,9 +309,6 @@ static blk_qc_t brd_make_request(struct request_queue *q, struct bio *bio) sector += len >> SECTOR_SHIFT; } -out: - bio_endio(bio); - return BLK_QC_T_NONE; io_error: bio_io_error(bio); return BLK_QC_T_NONE; @@ -464,11 +413,6 @@ static struct brd_device *brd_alloc(int i) * is harmless) */ blk_queue_physical_block_size(brd->brd_queue, PAGE_SIZE); - - brd->brd_queue->limits.discard_granularity = PAGE_SIZE; - blk_queue_max_discard_sectors(brd->brd_queue, UINT_MAX); - brd->brd_queue->limits.discard_zeroes_data = 1; - queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, brd->brd_queue); #ifdef CONFIG_BLK_DEV_RAM_DAX queue_flag_set_unlocked(QUEUE_FLAG_DAX, brd->brd_queue); #endif -- 2.11.0