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 int 13 xfs_rw_bdev( 14 struct block_device *bdev, 15 sector_t sector, 16 unsigned int count, 17 char *data, 18 unsigned int op) 19 20 { 21 unsigned int is_vmalloc = is_vmalloc_addr(data); 22 unsigned int left = count; 23 int error; 24 struct bio *bio; 25 26 if (is_vmalloc && op == REQ_OP_WRITE) 27 flush_kernel_vmap_range(data, count); 28 29 bio = bio_alloc(bdev, bio_max_vecs(left), op | REQ_META | REQ_SYNC, 30 GFP_KERNEL); 31 bio->bi_iter.bi_sector = sector; 32 33 do { 34 struct page *page = kmem_to_page(data); 35 unsigned int off = offset_in_page(data); 36 unsigned int len = min_t(unsigned, left, PAGE_SIZE - off); 37 38 while (bio_add_page(bio, page, len, off) != len) { 39 struct bio *prev = bio; 40 41 bio = bio_alloc(prev->bi_bdev, bio_max_vecs(left), 42 prev->bi_opf, GFP_KERNEL); 43 bio->bi_iter.bi_sector = bio_end_sector(prev); 44 bio_chain(prev, bio); 45 46 submit_bio(prev); 47 } 48 49 data += len; 50 left -= len; 51 } while (left > 0); 52 53 error = submit_bio_wait(bio); 54 bio_put(bio); 55 56 if (is_vmalloc && op == REQ_OP_READ) 57 invalidate_kernel_vmap_range(data, count); 58 return error; 59 } 60