diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/bio.c | 227 |
1 files changed, 182 insertions, 45 deletions
@@ -25,6 +25,7 @@ #include <linux/module.h> #include <linux/mempool.h> #include <linux/workqueue.h> +#include <scsi/sg.h> /* for struct sg_iovec */ #define BIO_POOL_SIZE 256 @@ -546,22 +547,34 @@ out_bmd: return ERR_PTR(ret); } -static struct bio *__bio_map_user(request_queue_t *q, struct block_device *bdev, - unsigned long uaddr, unsigned int len, - int write_to_vm) +static struct bio *__bio_map_user_iov(request_queue_t *q, + struct block_device *bdev, + struct sg_iovec *iov, int iov_count, + int write_to_vm) { - unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; - unsigned long start = uaddr >> PAGE_SHIFT; - const int nr_pages = end - start; - int ret, offset, i; + int i, j; + int nr_pages = 0; struct page **pages; struct bio *bio; + int cur_page = 0; + int ret, offset; - /* - * transfer and buffer must be aligned to at least hardsector - * size for now, in the future we can relax this restriction - */ - if ((uaddr & queue_dma_alignment(q)) || (len & queue_dma_alignment(q))) + for (i = 0; i < iov_count; i++) { + unsigned long uaddr = (unsigned long)iov[i].iov_base; + unsigned long len = iov[i].iov_len; + unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; + unsigned long start = uaddr >> PAGE_SHIFT; + + nr_pages += end - start; + /* + * transfer and buffer must be aligned to at least hardsector + * size for now, in the future we can relax this restriction + */ + if ((uaddr & queue_dma_alignment(q)) || (len & queue_dma_alignment(q))) + return ERR_PTR(-EINVAL); + } + + if (!nr_pages) return ERR_PTR(-EINVAL); bio = bio_alloc(GFP_KERNEL, nr_pages); @@ -573,42 +586,54 @@ static struct bio *__bio_map_user(request_queue_t *q, struct block_device *bdev, if (!pages) goto out; - down_read(¤t->mm->mmap_sem); - ret = get_user_pages(current, current->mm, uaddr, nr_pages, - write_to_vm, 0, pages, NULL); - up_read(¤t->mm->mmap_sem); - - if (ret < nr_pages) - goto out; - - bio->bi_bdev = bdev; - - offset = uaddr & ~PAGE_MASK; - for (i = 0; i < nr_pages; i++) { - unsigned int bytes = PAGE_SIZE - offset; - - if (len <= 0) - break; - - if (bytes > len) - bytes = len; + memset(pages, 0, nr_pages * sizeof(struct page *)); + + for (i = 0; i < iov_count; i++) { + unsigned long uaddr = (unsigned long)iov[i].iov_base; + unsigned long len = iov[i].iov_len; + unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; + unsigned long start = uaddr >> PAGE_SHIFT; + const int local_nr_pages = end - start; + const int page_limit = cur_page + local_nr_pages; + + down_read(¤t->mm->mmap_sem); + ret = get_user_pages(current, current->mm, uaddr, + local_nr_pages, + write_to_vm, 0, &pages[cur_page], NULL); + up_read(¤t->mm->mmap_sem); + + if (ret < local_nr_pages) + goto out_unmap; + + + offset = uaddr & ~PAGE_MASK; + for (j = cur_page; j < page_limit; j++) { + unsigned int bytes = PAGE_SIZE - offset; + + if (len <= 0) + break; + + if (bytes > len) + bytes = len; + + /* + * sorry... + */ + if (__bio_add_page(q, bio, pages[j], bytes, offset) < bytes) + break; + + len -= bytes; + offset = 0; + } + cur_page = j; /* - * sorry... + * release the pages we didn't map into the bio, if any */ - if (__bio_add_page(q, bio, pages[i], bytes, offset) < bytes) - break; - - len -= bytes; - offset = 0; + while (j < page_limit) + page_cache_release(pages[j++]); } - /* - * release the pages we didn't map into the bio, if any - */ - while (i < nr_pages) - page_cache_release(pages[i++]); - kfree(pages); /* @@ -617,9 +642,17 @@ static struct bio *__bio_map_user(request_queue_t *q, struct block_device *bdev, if (!write_to_vm) bio->bi_rw |= (1 << BIO_RW); + bio->bi_bdev = bdev; bio->bi_flags |= (1 << BIO_USER_MAPPED); return bio; -out: + + out_unmap: + for (i = 0; i < nr_pages; i++) { + if(!pages[i]) + break; + page_cache_release(pages[i]); + } + out: kfree(pages); bio_put(bio); return ERR_PTR(ret); @@ -639,9 +672,33 @@ out: struct bio *bio_map_user(request_queue_t *q, struct block_device *bdev, unsigned long uaddr, unsigned int len, int write_to_vm) { + struct sg_iovec iov; + + iov.iov_base = (__user void *)uaddr; + iov.iov_len = len; + + return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm); +} + +/** + * bio_map_user_iov - map user sg_iovec table into bio + * @q: the request_queue_t for the bio + * @bdev: destination block device + * @iov: the iovec. + * @iov_count: number of elements in the iovec + * @write_to_vm: bool indicating writing to pages or not + * + * 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(request_queue_t *q, struct block_device *bdev, + struct sg_iovec *iov, int iov_count, + int write_to_vm) +{ struct bio *bio; + int len = 0, i; - bio = __bio_map_user(q, bdev, uaddr, len, write_to_vm); + bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm); if (IS_ERR(bio)) return bio; @@ -654,6 +711,9 @@ struct bio *bio_map_user(request_queue_t *q, struct block_device *bdev, */ bio_get(bio); + for (i = 0; i < iov_count; i++) + len += iov[i].iov_len; + if (bio->bi_size == len) return bio; @@ -698,6 +758,82 @@ void bio_unmap_user(struct bio *bio) bio_put(bio); } +static int bio_map_kern_endio(struct bio *bio, unsigned int bytes_done, int err) +{ + if (bio->bi_size) + return 1; + + bio_put(bio); + return 0; +} + + +static struct bio *__bio_map_kern(request_queue_t *q, void *data, + unsigned int len, unsigned int 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; + int offset, i; + struct bio *bio; + + bio = bio_alloc(gfp_mask, nr_pages); + if (!bio) + return ERR_PTR(-ENOMEM); + + 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 (__bio_add_page(q, bio, virt_to_page(data), bytes, + offset) < bytes) + break; + + data += bytes; + len -= bytes; + offset = 0; + } + + bio->bi_end_io = bio_map_kern_endio; + return bio; +} + +/** + * bio_map_kern - map kernel address into bio + * @q: the request_queue_t 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(request_queue_t *q, void *data, unsigned int len, + unsigned int gfp_mask) +{ + struct bio *bio; + + bio = __bio_map_kern(q, data, len, gfp_mask); + if (IS_ERR(bio)) + return bio; + + if (bio->bi_size == len) + return bio; + + /* + * Don't support partial mappings. + */ + bio_put(bio); + return ERR_PTR(-EINVAL); +} + /* * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions * for performing direct-IO in BIOs. @@ -1085,6 +1221,7 @@ EXPORT_SYMBOL(bio_add_page); EXPORT_SYMBOL(bio_get_nr_vecs); EXPORT_SYMBOL(bio_map_user); EXPORT_SYMBOL(bio_unmap_user); +EXPORT_SYMBOL(bio_map_kern); EXPORT_SYMBOL(bio_pair_release); EXPORT_SYMBOL(bio_split); EXPORT_SYMBOL(bio_split_pool); |