diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/bio.c | 90 |
1 files changed, 90 insertions, 0 deletions
@@ -937,6 +937,95 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, return ERR_PTR(-EINVAL); } +static void bio_copy_kern_endio(struct bio *bio, int err) +{ + struct bio_vec *bvec; + const int read = bio_data_dir(bio) == READ; + char *p = bio->bi_private; + int i; + + __bio_for_each_segment(bvec, bio, i, 0) { + char *addr = page_address(bvec->bv_page); + + if (read && !err) + memcpy(p, addr, bvec->bv_len); + + __free_page(bvec->bv_page); + p += bvec->bv_len; + } + + bio_put(bio); +} + +/** + * bio_copy_kern - copy kernel address into bio + * @q: the struct request_queue for the bio + * @data: pointer to buffer to copy + * @len: length in bytes + * @gfp_mask: allocation flags for bio and page allocation + * + * copy the kernel address into a bio suitable for io to a block + * device. Returns an error pointer in case of error. + */ +struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, + gfp_t gfp_mask, int reading) +{ + unsigned long kaddr = (unsigned long)data; + unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; + unsigned long start = kaddr >> PAGE_SHIFT; + const int nr_pages = end - start; + struct bio *bio; + struct bio_vec *bvec; + int i, ret; + + bio = bio_alloc(gfp_mask, nr_pages); + if (!bio) + return ERR_PTR(-ENOMEM); + + while (len) { + struct page *page; + unsigned int bytes = PAGE_SIZE; + + if (bytes > len) + bytes = len; + + page = alloc_page(q->bounce_gfp | gfp_mask); + if (!page) { + ret = -ENOMEM; + goto cleanup; + } + + if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) { + ret = -EINVAL; + goto cleanup; + } + + len -= bytes; + } + + if (!reading) { + void *p = data; + + bio_for_each_segment(bvec, bio, i) { + char *addr = page_address(bvec->bv_page); + + memcpy(addr, p, bvec->bv_len); + p += bvec->bv_len; + } + } + + bio->bi_private = data; + bio->bi_end_io = bio_copy_kern_endio; + return bio; +cleanup: + bio_for_each_segment(bvec, bio, i) + __free_page(bvec->bv_page); + + bio_put(bio); + + return ERR_PTR(ret); +} + /* * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions * for performing direct-IO in BIOs. @@ -1273,6 +1362,7 @@ EXPORT_SYMBOL(bio_get_nr_vecs); EXPORT_SYMBOL(bio_map_user); EXPORT_SYMBOL(bio_unmap_user); EXPORT_SYMBOL(bio_map_kern); +EXPORT_SYMBOL(bio_copy_kern); EXPORT_SYMBOL(bio_pair_release); EXPORT_SYMBOL(bio_split); EXPORT_SYMBOL(bio_split_pool); |