1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2019 Christoph Hellwig. 4 */ 5 #include "xfs.h" 6 7 static inline unsigned int bio_max_vecs(unsigned int count) 8 { 9 return bio_max_segs(howmany(count, PAGE_SIZE)); 10 } 11 12 static void 13 xfs_flush_bdev_async_endio( 14 struct bio *bio) 15 { 16 complete(bio->bi_private); 17 } 18 19 /* 20 * Submit a request for an async cache flush to run. If the request queue does 21 * not require flush operations, just skip it altogether. If the caller needs 22 * to wait for the flush completion at a later point in time, they must supply a 23 * valid completion. This will be signalled when the flush completes. The 24 * caller never sees the bio that is issued here. 25 */ 26 void 27 xfs_flush_bdev_async( 28 struct bio *bio, 29 struct block_device *bdev, 30 struct completion *done) 31 { 32 struct request_queue *q = bdev->bd_disk->queue; 33 34 if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { 35 complete(done); 36 return; 37 } 38 39 bio_init(bio, NULL, 0); 40 bio_set_dev(bio, bdev); 41 bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC; 42 bio->bi_private = done; 43 bio->bi_end_io = xfs_flush_bdev_async_endio; 44 45 submit_bio(bio); 46 } 47 int 48 xfs_rw_bdev( 49 struct block_device *bdev, 50 sector_t sector, 51 unsigned int count, 52 char *data, 53 unsigned int op) 54 55 { 56 unsigned int is_vmalloc = is_vmalloc_addr(data); 57 unsigned int left = count; 58 int error; 59 struct bio *bio; 60 61 if (is_vmalloc && op == REQ_OP_WRITE) 62 flush_kernel_vmap_range(data, count); 63 64 bio = bio_alloc(GFP_KERNEL, bio_max_vecs(left)); 65 bio_set_dev(bio, bdev); 66 bio->bi_iter.bi_sector = sector; 67 bio->bi_opf = op | REQ_META | REQ_SYNC; 68 69 do { 70 struct page *page = kmem_to_page(data); 71 unsigned int off = offset_in_page(data); 72 unsigned int len = min_t(unsigned, left, PAGE_SIZE - off); 73 74 while (bio_add_page(bio, page, len, off) != len) { 75 struct bio *prev = bio; 76 77 bio = bio_alloc(GFP_KERNEL, bio_max_vecs(left)); 78 bio_copy_dev(bio, prev); 79 bio->bi_iter.bi_sector = bio_end_sector(prev); 80 bio->bi_opf = prev->bi_opf; 81 bio_chain(prev, bio); 82 83 submit_bio(prev); 84 } 85 86 data += len; 87 left -= len; 88 } while (left > 0); 89 90 error = submit_bio_wait(bio); 91 bio_put(bio); 92 93 if (is_vmalloc && op == REQ_OP_READ) 94 invalidate_kernel_vmap_range(data, count); 95 return error; 96 } 97