diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/bio.c | 510 | ||||
| -rw-r--r-- | block/blk-map.c | 508 | ||||
| -rw-r--r-- | block/blk.h | 4 |
3 files changed, 513 insertions, 509 deletions
diff --git a/block/bio.c b/block/bio.c index 11e6aac35092..21cbaa6a1c20 100644 --- a/block/bio.c +++ b/block/bio.c @@ -780,7 +780,7 @@ static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *bio, * * This should only be used by passthrough bios. */ -static int __bio_add_pc_page(struct request_queue *q, struct bio *bio, +int __bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page, unsigned int len, unsigned int offset, bool *same_page) { @@ -1194,90 +1194,6 @@ void bio_list_copy_data(struct bio *dst, struct bio *src) } EXPORT_SYMBOL(bio_list_copy_data); -struct bio_map_data { - int is_our_pages; - struct iov_iter iter; - struct iovec iov[]; -}; - -static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data, - gfp_t gfp_mask) -{ - struct bio_map_data *bmd; - if (data->nr_segs > UIO_MAXIOV) - return NULL; - - bmd = kmalloc(struct_size(bmd, iov, data->nr_segs), gfp_mask); - if (!bmd) - return NULL; - memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs); - bmd->iter = *data; - bmd->iter.iov = bmd->iov; - return bmd; -} - -/** - * bio_copy_from_iter - copy all pages from iov_iter to bio - * @bio: The &struct bio which describes the I/O as destination - * @iter: iov_iter as source - * - * Copy all pages from iov_iter to bio. - * Returns 0 on success, or error on failure. - */ -static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter) -{ - struct bio_vec *bvec; - struct bvec_iter_all iter_all; - - bio_for_each_segment_all(bvec, bio, iter_all) { - ssize_t ret; - - ret = copy_page_from_iter(bvec->bv_page, - bvec->bv_offset, - bvec->bv_len, - iter); - - if (!iov_iter_count(iter)) - break; - - if (ret < bvec->bv_len) - return -EFAULT; - } - - return 0; -} - -/** - * bio_copy_to_iter - copy all pages from bio to iov_iter - * @bio: The &struct bio which describes the I/O as source - * @iter: iov_iter as destination - * - * Copy all pages from bio to iov_iter. - * Returns 0 on success, or error on failure. - */ -static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter) -{ - struct bio_vec *bvec; - struct bvec_iter_all iter_all; - - bio_for_each_segment_all(bvec, bio, iter_all) { - ssize_t ret; - - ret = copy_page_to_iter(bvec->bv_page, - bvec->bv_offset, - bvec->bv_len, - &iter); - - if (!iov_iter_count(&iter)) - break; - - if (ret < bvec->bv_len) - return -EFAULT; - } - - return 0; -} - void bio_free_pages(struct bio *bio) { struct bio_vec *bvec; @@ -1288,430 +1204,6 @@ void bio_free_pages(struct bio *bio) } EXPORT_SYMBOL(bio_free_pages); -/** - * bio_uncopy_user - finish previously mapped bio - * @bio: bio being terminated - * - * Free pages allocated from bio_copy_user_iov() and write back data - * to user space in case of a read. - */ -int bio_uncopy_user(struct bio *bio) -{ - struct bio_map_data *bmd = bio->bi_private; - int ret = 0; - - if (!bio_flagged(bio, BIO_NULL_MAPPED)) { - /* - * if we're in a workqueue, the request is orphaned, so - * don't copy into a random user address space, just free - * and return -EINTR so user space doesn't expect any data. - */ - if (!current->mm) - ret = -EINTR; - else if (bio_data_dir(bio) == READ) - ret = bio_copy_to_iter(bio, bmd->iter); - if (bmd->is_our_pages) - bio_free_pages(bio); - } - kfree(bmd); - bio_put(bio); - return ret; -} - -/** - * bio_copy_user_iov - copy user data to bio - * @q: destination block queue - * @map_data: pointer to the rq_map_data holding pages (if necessary) - * @iter: iovec iterator - * @gfp_mask: memory allocation flags - * - * Prepares and returns a bio for indirect user io, bouncing data - * to/from kernel pages as necessary. Must be paired with - * call bio_uncopy_user() on io completion. - */ -struct bio *bio_copy_user_iov(struct request_queue *q, - struct rq_map_data *map_data, - struct iov_iter *iter, - gfp_t gfp_mask) -{ - struct bio_map_data *bmd; - struct page *page; - struct bio *bio; - int i = 0, ret; - int nr_pages; - unsigned int len = iter->count; - unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0; - - bmd = bio_alloc_map_data(iter, gfp_mask); - if (!bmd) - return ERR_PTR(-ENOMEM); - - /* - * We need to do a deep copy of the iov_iter including the iovecs. - * The caller provided iov might point to an on-stack or otherwise - * shortlived one. - */ - bmd->is_our_pages = map_data ? 0 : 1; - - nr_pages = DIV_ROUND_UP(offset + len, PAGE_SIZE); - if (nr_pages > BIO_MAX_PAGES) - nr_pages = BIO_MAX_PAGES; - - ret = -ENOMEM; - bio = bio_kmalloc(gfp_mask, nr_pages); - if (!bio) - goto out_bmd; - - ret = 0; - - if (map_data) { - nr_pages = 1 << map_data->page_order; - i = map_data->offset / PAGE_SIZE; - } - while (len) { - unsigned int bytes = PAGE_SIZE; - - bytes -= offset; - - if (bytes > len) - bytes = len; - - if (map_data) { - if (i == map_data->nr_entries * nr_pages) { - ret = -ENOMEM; - break; - } - - page = map_data->pages[i / nr_pages]; - page += (i % nr_pages); - - i++; - } else { - page = alloc_page(q->bounce_gfp | gfp_mask); - if (!page) { - ret = -ENOMEM; - break; - } - } - - if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) { - if (!map_data) - __free_page(page); - break; - } - - len -= bytes; - offset = 0; - } - - if (ret) - goto cleanup; - - if (map_data) - map_data->offset += bio->bi_iter.bi_size; - - /* - * success - */ - if ((iov_iter_rw(iter) == WRITE && (!map_data || !map_data->null_mapped)) || - (map_data && map_data->from_user)) { - ret = bio_copy_from_iter(bio, iter); - if (ret) - goto cleanup; - } else { - if (bmd->is_our_pages) - zero_fill_bio(bio); - iov_iter_advance(iter, bio->bi_iter.bi_size); - } - - bio->bi_private = bmd; - if (map_data && map_data->null_mapped) - bio_set_flag(bio, BIO_NULL_MAPPED); - return bio; -cleanup: - if (!map_data) - bio_free_pages(bio); - bio_put(bio); -out_bmd: - kfree(bmd); - return ERR_PTR(ret); -} - -/** - * bio_map_user_iov - map user iovec into bio - * @q: the struct request_queue for the bio - * @iter: iovec iterator - * @gfp_mask: memory allocation flags - * - * Map the user space address into a bio suitable for io to a block - * device. Returns an error pointer in case of error. - */ -struct bio *bio_map_user_iov(struct request_queue *q, - struct iov_iter *iter, - gfp_t gfp_mask) -{ - int j; - struct bio *bio; - int ret; - - if (!iov_iter_count(iter)) - return ERR_PTR(-EINVAL); - - bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_PAGES)); - if (!bio) - return ERR_PTR(-ENOMEM); - - while (iov_iter_count(iter)) { - struct page **pages; - ssize_t bytes; - size_t offs, added = 0; - int npages; - - bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs); - if (unlikely(bytes <= 0)) { - ret = bytes ? bytes : -EFAULT; - goto out_unmap; - } - - npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE); - - if (unlikely(offs & queue_dma_alignment(q))) { - ret = -EINVAL; - j = 0; - } else { - for (j = 0; j < npages; j++) { - struct page *page = pages[j]; - unsigned int n = PAGE_SIZE - offs; - bool same_page = false; - - if (n > bytes) - n = bytes; - - if (!__bio_add_pc_page(q, bio, page, n, offs, - &same_page)) { - if (same_page) - put_page(page); - break; - } - - added += n; - bytes -= n; - offs = 0; - } - iov_iter_advance(iter, added); - } - /* - * release the pages we didn't map into the bio, if any - */ - while (j < npages) - put_page(pages[j++]); - kvfree(pages); - /* couldn't stuff something into bio? */ - if (bytes) - break; - } - - bio_set_flag(bio, BIO_USER_MAPPED); - - /* - * subtle -- if bio_map_user_iov() ended up bouncing a bio, - * it would normally disappear when its bi_end_io is run. - * however, we need it for the unmap, so grab an extra - * reference to it - */ - bio_get(bio); - return bio; - - out_unmap: - bio_release_pages(bio, false); - bio_put(bio); - return ERR_PTR(ret); -} - -/** - * bio_unmap_user - unmap a bio - * @bio: the bio being unmapped - * - * Unmap a bio previously mapped by bio_map_user_iov(). Must be called from - * process context. - * - * bio_unmap_user() may sleep. - */ -void bio_unmap_user(struct bio *bio) -{ - bio_release_pages(bio, bio_data_dir(bio) == READ); - bio_put(bio); - bio_put(bio); -} - -static void bio_invalidate_vmalloc_pages(struct bio *bio) -{ -#ifdef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE - if (bio->bi_private && !op_is_write(bio_op(bio))) { - unsigned long i, len = 0; - - for (i = 0; i < bio->bi_vcnt; i++) - len += bio->bi_io_vec[i].bv_len; - invalidate_kernel_vmap_range(bio->bi_private, len); - } -#endif -} - -static void bio_map_kern_endio(struct bio *bio) -{ - bio_invalidate_vmalloc_pages(bio); - bio_put(bio); -} - -/** - * bio_map_kern - map kernel address into bio - * @q: the struct request_queue for the bio - * @data: pointer to buffer to map - * @len: length in bytes - * @gfp_mask: allocation flags for bio allocation - * - * Map the kernel address into a bio suitable for io to a block - * device. Returns an error pointer in case of error. - */ -struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, - gfp_t gfp_mask) -{ - 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; - bool is_vmalloc = is_vmalloc_addr(data); - struct page *page; - int offset, i; - struct bio *bio; - - bio = bio_kmalloc(gfp_mask, nr_pages); - if (!bio) - return ERR_PTR(-ENOMEM); - - if (is_vmalloc) { - flush_kernel_vmap_range(data, len); - bio->bi_private = data; - } - - offset = offset_in_page(kaddr); - for (i = 0; i < nr_pages; i++) { - unsigned int bytes = PAGE_SIZE - offset; - - if (len <= 0) - break; - - if (bytes > len) - bytes = len; - - if (!is_vmalloc) - page = virt_to_page(data); - else - page = vmalloc_to_page(data); - if (bio_add_pc_page(q, bio, page, bytes, - offset) < bytes) { - /* we don't support partial mappings */ - bio_put(bio); - return ERR_PTR(-EINVAL); - } - - data += bytes; - len -= bytes; - offset = 0; - } - - bio->bi_end_io = bio_map_kern_endio; - return bio; -} - -static void bio_copy_kern_endio(struct bio *bio) -{ - bio_free_pages(bio); - bio_put(bio); -} - -static void bio_copy_kern_endio_read(struct bio *bio) -{ - char *p = bio->bi_private; - struct bio_vec *bvec; - struct bvec_iter_all iter_all; - - bio_for_each_segment_all(bvec, bio, iter_all) { - memcpy(p, page_address(bvec->bv_page), bvec->bv_len); - p += bvec->bv_len; - } - - bio_copy_kern_endio(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 - * @reading: data direction is READ - * - * 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; - struct bio *bio; - void *p = data; - int nr_pages = 0; - - /* - * Overflow, abort - */ - if (end < start) - return ERR_PTR(-EINVAL); - - nr_pages = end - start; - bio = bio_kmalloc(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) - goto cleanup; - - if (!reading) - memcpy(page_address(page), p, bytes); - - if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) - break; - - len -= bytes; - p += bytes; - } - - if (reading) { - bio->bi_end_io = bio_copy_kern_endio_read; - bio->bi_private = data; - } else { - bio->bi_end_io = bio_copy_kern_endio; - } - - return bio; - -cleanup: - bio_free_pages(bio); - bio_put(bio); - return ERR_PTR(-ENOMEM); -} - /* * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions * for performing direct-IO in BIOs. diff --git a/block/blk-map.c b/block/blk-map.c index b0790268ed9d..b72c361911a4 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -11,6 +11,514 @@ #include "blk.h" +struct bio_map_data { + int is_our_pages; + struct iov_iter iter; + struct iovec iov[]; +}; + +static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data, + gfp_t gfp_mask) +{ + struct bio_map_data *bmd; + + if (data->nr_segs > UIO_MAXIOV) + return NULL; + + bmd = kmalloc(struct_size(bmd, iov, data->nr_segs), gfp_mask); + if (!bmd) + return NULL; + memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs); + bmd->iter = *data; + bmd->iter.iov = bmd->iov; + return bmd; +} + +/** + * bio_copy_from_iter - copy all pages from iov_iter to bio + * @bio: The &struct bio which describes the I/O as destination + * @iter: iov_iter as source + * + * Copy all pages from iov_iter to bio. + * Returns 0 on success, or error on failure. + */ +static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter) +{ + struct bio_vec *bvec; + struct bvec_iter_all iter_all; + + bio_for_each_segment_all(bvec, bio, iter_all) { + ssize_t ret; + + ret = copy_page_from_iter(bvec->bv_page, + bvec->bv_offset, + bvec->bv_len, + iter); + + if (!iov_iter_count(iter)) + break; + + if (ret < bvec->bv_len) + return -EFAULT; + } + + return 0; +} + +/** + * bio_copy_to_iter - copy all pages from bio to iov_iter + * @bio: The &struct bio which describes the I/O as source + * @iter: iov_iter as destination + * + * Copy all pages from bio to iov_iter. + * Returns 0 on success, or error on failure. + */ +static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter) +{ + struct bio_vec *bvec; + struct bvec_iter_all iter_all; + + bio_for_each_segment_all(bvec, bio, iter_all) { + ssize_t ret; + + ret = copy_page_to_iter(bvec->bv_page, + bvec->bv_offset, + bvec->bv_len, + &iter); + + if (!iov_iter_count(&iter)) + break; + + if (ret < bvec->bv_len) + return -EFAULT; + } + + return 0; +} + +/** + * bio_uncopy_user - finish previously mapped bio + * @bio: bio being terminated + * + * Free pages allocated from bio_copy_user_iov() and write back data + * to user space in case of a read. + */ +static int bio_uncopy_user(struct bio *bio) +{ + struct bio_map_data *bmd = bio->bi_private; + int ret = 0; + + if (!bio_flagged(bio, BIO_NULL_MAPPED)) { + /* + * if we're in a workqueue, the request is orphaned, so + * don't copy into a random user address space, just free + * and return -EINTR so user space doesn't expect any data. + */ + if (!current->mm) + ret = -EINTR; + else if (bio_data_dir(bio) == READ) + ret = bio_copy_to_iter(bio, bmd->iter); + if (bmd->is_our_pages) + bio_free_pages(bio); + } + kfree(bmd); + bio_put(bio); + return ret; +} + +/** + * bio_copy_user_iov - copy user data to bio + * @q: destination block queue + * @map_data: pointer to the rq_map_data holding pages (if necessary) + * @iter: iovec iterator + * @gfp_mask: memory allocation flags + * + * Prepares and returns a bio for indirect user io, bouncing data + * to/from kernel pages as necessary. Must be paired with + * call bio_uncopy_user() on io completion. + */ +static struct bio *bio_copy_user_iov(struct request_queue *q, + struct rq_map_data *map_data, struct iov_iter *iter, + gfp_t gfp_mask) +{ + struct bio_map_data *bmd; + struct page *page; + struct bio *bio; + int i = 0, ret; + int nr_pages; + unsigned int len = iter->count; + unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0; + + bmd = bio_alloc_map_data(iter, gfp_mask); + if (!bmd) + return ERR_PTR(-ENOMEM); + + /* + * We need to do a deep copy of the iov_iter including the iovecs. + * The caller provided iov might point to an on-stack or otherwise + * shortlived one. + */ + bmd->is_our_pages = map_data ? 0 : 1; + + nr_pages = DIV_ROUND_UP(offset + len, PAGE_SIZE); + if (nr_pages > BIO_MAX_PAGES) + nr_pages = BIO_MAX_PAGES; + + ret = -ENOMEM; + bio = bio_kmalloc(gfp_mask, nr_pages); + if (!bio) + goto out_bmd; + + ret = 0; + + if (map_data) { + nr_pages = 1 << map_data->page_order; + i = map_data->offset / PAGE_SIZE; + } + while (len) { + unsigned int bytes = PAGE_SIZE; + + bytes -= offset; + + if (bytes > len) + bytes = len; + + if (map_data) { + if (i == map_data->nr_entries * nr_pages) { + ret = -ENOMEM; + break; + } + + page = map_data->pages[i / nr_pages]; + page += (i % nr_pages); + + i++; + } else { + page = alloc_page(q->bounce_gfp | gfp_mask); + if (!page) { + ret = -ENOMEM; + break; + } + } + + if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) { + if (!map_data) + __free_page(page); + break; + } + + len -= bytes; + offset = 0; + } + + if (ret) + goto cleanup; + + if (map_data) + map_data->offset += bio->bi_iter.bi_size; + + /* + * success + */ + if ((iov_iter_rw(iter) == WRITE && + (!map_data || !map_data->null_mapped)) || + (map_data && map_data->from_user)) { + ret = bio_copy_from_iter(bio, iter); + if (ret) + goto cleanup; + } else { + if (bmd->is_our_pages) + zero_fill_bio(bio); + iov_iter_advance(iter, bio->bi_iter.bi_size); + } + + bio->bi_private = bmd; + if (map_data && map_data->null_mapped) + bio_set_flag(bio, BIO_NULL_MAPPED); + return bio; +cleanup: + if (!map_data) + bio_free_pages(bio); + bio_put(bio); +out_bmd: + kfree(bmd); + return ERR_PTR(ret); +} + +/** + * bio_map_user_iov - map user iovec into bio + * @q: the struct request_queue for the bio + * @iter: iovec iterator + * @gfp_mask: memory allocation flags + * + * Map the user space address into a bio suitable for io to a block + * device. Returns an error pointer in case of error. + */ +static struct bio *bio_map_user_iov(struct request_queue *q, + struct iov_iter *iter, gfp_t gfp_mask) +{ + int j; + struct bio *bio; + int ret; + + if (!iov_iter_count(iter)) + return ERR_PTR(-EINVAL); + + bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_PAGES)); + if (!bio) + return ERR_PTR(-ENOMEM); + + while (iov_iter_count(iter)) { + struct page **pages; + ssize_t bytes; + size_t offs, added = 0; + int npages; + + bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs); + if (unlikely(bytes <= 0)) { + ret = bytes ? bytes : -EFAULT; + goto out_unmap; + } + + npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE); + + if (unlikely(offs & queue_dma_alignment(q))) { + ret = -EINVAL; + j = 0; + } else { + for (j = 0; j < npages; j++) { + struct page *page = pages[j]; + unsigned int n = PAGE_SIZE - offs; + bool same_page = false; + + if (n > bytes) + n = bytes; + + if (!__bio_add_pc_page(q, bio, page, n, offs, + &same_page)) { + if (same_page) + put_page(page); + break; + } + + added += n; + bytes -= n; + offs = 0; + } + iov_iter_advance(iter, added); + } + /* + * release the pages we didn't map into the bio, if any + */ + while (j < npages) + put_page(pages[j++]); + kvfree(pages); + /* couldn't stuff something into bio? */ + if (bytes) + break; + } + + bio_set_flag(bio, BIO_USER_MAPPED); + + /* + * subtle -- if bio_map_user_iov() ended up bouncing a bio, + * it would normally disappear when its bi_end_io is run. + * however, we need it for the unmap, so grab an extra + * reference to it + */ + bio_get(bio); + return bio; + + out_unmap: + bio_release_pages(bio, false); + bio_put(bio); + return ERR_PTR(ret); +} + +/** + * bio_unmap_user - unmap a bio + * @bio: the bio being unmapped + * + * Unmap a bio previously mapped by bio_map_user_iov(). Must be called from + * process context. + * + * bio_unmap_user() may sleep. + */ +static void bio_unmap_user(struct bio *bio) +{ + bio_release_pages(bio, bio_data_dir(bio) == READ); + bio_put(bio); + bio_put(bio); +} + +static void bio_invalidate_vmalloc_pages(struct bio *bio) +{ +#ifdef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE + if (bio->bi_private && !op_is_write(bio_op(bio))) { + unsigned long i, len = 0; + + for (i = 0; i < bio->bi_vcnt; i++) + len += bio->bi_io_vec[i].bv_len; + invalidate_kernel_vmap_range(bio->bi_private, len); + } +#endif +} + +static void bio_map_kern_endio(struct bio *bio) +{ + bio_invalidate_vmalloc_pages(bio); + bio_put(bio); +} + +/** + * bio_map_kern - map kernel address into bio + * @q: the struct request_queue for the bio + * @data: pointer to buffer to map + * @len: length in bytes + * @gfp_mask: allocation flags for bio allocation + * + * Map the kernel address into a bio suitable for io to a block + * device. Returns an error pointer in case of error. + */ +static struct bio *bio_map_kern(struct request_queue *q, void *data, + unsigned int len, gfp_t gfp_mask) +{ + 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; + bool is_vmalloc = is_vmalloc_addr(data); + struct page *page; + int offset, i; + struct bio *bio; + + bio = bio_kmalloc(gfp_mask, nr_pages); + if (!bio) + return ERR_PTR(-ENOMEM); + + if (is_vmalloc) { + flush_kernel_vmap_range(data, len); + bio->bi_private = data; + } + + offset = offset_in_page(kaddr); + for (i = 0; i < nr_pages; i++) { + unsigned int bytes = PAGE_SIZE - offset; + + if (len <= 0) + break; + + if (bytes > len) + bytes = len; + + if (!is_vmalloc) + page = virt_to_page(data); + else + page = vmalloc_to_page(data); + if (bio_add_pc_page(q, bio, page, bytes, + offset) < bytes) { + /* we don't support partial mappings */ + bio_put(bio); + return ERR_PTR(-EINVAL); + } + + data += bytes; + len -= bytes; + offset = 0; + } + + bio->bi_end_io = bio_map_kern_endio; + return bio; +} + +static void bio_copy_kern_endio(struct bio *bio) +{ + bio_free_pages(bio); + bio_put(bio); +} + +static void bio_copy_kern_endio_read(struct bio *bio) +{ + char *p = bio->bi_private; + struct bio_vec *bvec; + struct bvec_iter_all iter_all; + + bio_for_each_segment_all(bvec, bio, iter_all) { + memcpy(p, page_address(bvec->bv_page), bvec->bv_len); + p += bvec->bv_len; + } + + bio_copy_kern_endio(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 + * @reading: data direction is READ + * + * copy the kernel address into a bio suitable for io to a block + * device. Returns an error pointer in case of error. + */ +static 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; + struct bio *bio; + void *p = data; + int nr_pages = 0; + + /* + * Overflow, abort + */ + if (end < start) + return ERR_PTR(-EINVAL); + + nr_pages = end - start; + bio = bio_kmalloc(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) + goto cleanup; + + if (!reading) + memcpy(page_address(page), p, bytes); + + if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) + break; + + len -= bytes; + p += bytes; + } + + if (reading) { + bio->bi_end_io = bio_copy_kern_endio_read; + bio->bi_private = data; + } else { + bio->bi_end_io = bio_copy_kern_endio; + } + + return bio; + +cleanup: + bio_free_pages(bio); + bio_put(bio); + return ERR_PTR(-ENOMEM); +} + /* * Append a bio to a passthrough request. Only works if the bio can be merged * into the request based on the driver constraints. diff --git a/block/blk.h b/block/blk.h index 491e52fc0aa6..0a94ec68af32 100644 --- a/block/blk.h +++ b/block/blk.h @@ -484,4 +484,8 @@ static inline void part_nr_sects_write(struct hd_struct *part, sector_t size) struct request_queue *__blk_alloc_queue(int node_id); +int __bio_add_pc_page(struct request_queue *q, struct bio *bio, + struct page *page, unsigned int len, unsigned int offset, + bool *same_page); + #endif /* BLK_INTERNAL_H */ |