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, bdev, NULL, 0, REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC); 40 bio->bi_private = done; 41 bio->bi_end_io = xfs_flush_bdev_async_endio; 42 43 submit_bio(bio); 44 } 45 int 46 xfs_rw_bdev( 47 struct block_device *bdev, 48 sector_t sector, 49 unsigned int count, 50 char *data, 51 unsigned int op) 52 53 { 54 unsigned int is_vmalloc = is_vmalloc_addr(data); 55 unsigned int left = count; 56 int error; 57 struct bio *bio; 58 59 if (is_vmalloc && op == REQ_OP_WRITE) 60 flush_kernel_vmap_range(data, count); 61 62 bio = bio_alloc(bdev, bio_max_vecs(left), op | REQ_META | REQ_SYNC, 63 GFP_KERNEL); 64 bio->bi_iter.bi_sector = sector; 65 66 do { 67 struct page *page = kmem_to_page(data); 68 unsigned int off = offset_in_page(data); 69 unsigned int len = min_t(unsigned, left, PAGE_SIZE - off); 70 71 while (bio_add_page(bio, page, len, off) != len) { 72 struct bio *prev = bio; 73 74 bio = bio_alloc(prev->bi_bdev, bio_max_vecs(left), 75 prev->bi_opf, GFP_KERNEL); 76 bio->bi_iter.bi_sector = bio_end_sector(prev); 77 bio_chain(prev, bio); 78 79 submit_bio(prev); 80 } 81 82 data += len; 83 left -= len; 84 } while (left > 0); 85 86 error = submit_bio_wait(bio); 87 bio_put(bio); 88 89 if (is_vmalloc && op == REQ_OP_READ) 90 invalidate_kernel_vmap_range(data, count); 91 return error; 92 } 93