1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2010 Red Hat, Inc. 4 * Copyright (C) 2016-2023 Christoph Hellwig. 5 */ 6 #include <linux/iomap.h> 7 #include <linux/pagemap.h> 8 #include "internal.h" 9 #include "trace.h" 10 11 static void iomap_read_end_io(struct bio *bio) 12 { 13 int error = blk_status_to_errno(bio->bi_status); 14 struct folio_iter fi; 15 16 bio_for_each_folio_all(fi, bio) 17 iomap_finish_folio_read(fi.folio, fi.offset, fi.length, error); 18 bio_put(bio); 19 } 20 21 static void iomap_bio_submit_read(struct iomap_read_folio_ctx *ctx) 22 { 23 struct bio *bio = ctx->read_ctx; 24 25 if (bio) 26 submit_bio(bio); 27 } 28 29 static int iomap_bio_read_folio_range(const struct iomap_iter *iter, 30 struct iomap_read_folio_ctx *ctx, size_t plen) 31 { 32 struct folio *folio = ctx->cur_folio; 33 const struct iomap *iomap = &iter->iomap; 34 loff_t pos = iter->pos; 35 size_t poff = offset_in_folio(folio, pos); 36 loff_t length = iomap_length(iter); 37 sector_t sector; 38 struct bio *bio = ctx->read_ctx; 39 40 sector = iomap_sector(iomap, pos); 41 if (!bio || bio_end_sector(bio) != sector || 42 !bio_add_folio(bio, folio, plen, poff)) { 43 gfp_t gfp = mapping_gfp_constraint(folio->mapping, GFP_KERNEL); 44 gfp_t orig_gfp = gfp; 45 unsigned int nr_vecs = DIV_ROUND_UP(length, PAGE_SIZE); 46 47 if (bio) 48 submit_bio(bio); 49 50 if (ctx->rac) /* same as readahead_gfp_mask */ 51 gfp |= __GFP_NORETRY | __GFP_NOWARN; 52 bio = bio_alloc(iomap->bdev, bio_max_segs(nr_vecs), REQ_OP_READ, 53 gfp); 54 /* 55 * If the bio_alloc fails, try it again for a single page to 56 * avoid having to deal with partial page reads. This emulates 57 * what do_mpage_read_folio does. 58 */ 59 if (!bio) 60 bio = bio_alloc(iomap->bdev, 1, REQ_OP_READ, orig_gfp); 61 if (ctx->rac) 62 bio->bi_opf |= REQ_RAHEAD; 63 bio->bi_iter.bi_sector = sector; 64 bio->bi_end_io = iomap_read_end_io; 65 bio_add_folio_nofail(bio, folio, plen, poff); 66 ctx->read_ctx = bio; 67 } 68 return 0; 69 } 70 71 const struct iomap_read_ops iomap_bio_read_ops = { 72 .read_folio_range = iomap_bio_read_folio_range, 73 .submit_read = iomap_bio_submit_read, 74 }; 75 EXPORT_SYMBOL_GPL(iomap_bio_read_ops); 76 77 int iomap_bio_read_folio_range_sync(const struct iomap_iter *iter, 78 struct folio *folio, loff_t pos, size_t len) 79 { 80 const struct iomap *srcmap = iomap_iter_srcmap(iter); 81 struct bio_vec bvec; 82 struct bio bio; 83 84 bio_init(&bio, srcmap->bdev, &bvec, 1, REQ_OP_READ); 85 bio.bi_iter.bi_sector = iomap_sector(srcmap, pos); 86 bio_add_folio_nofail(&bio, folio, len, offset_in_folio(folio, pos)); 87 return submit_bio_wait(&bio); 88 } 89