On Tue, Mar 24, 2015 at 06:53:07PM +0800, Ming Lei wrote: > If you have better one, please just ignore this patchset.
Here is a straight forward port of my old one. It's got light testing but still could use a better description and a split up: --- >From a45b5053db5908954d340b05ef8a23e1ca43010a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig <[email protected]> Date: Fri, 16 Jan 2015 15:06:03 +0100 Subject: loop: convert to vfs_iter_read/write Signed-off-by: Christoph Hellwig <[email protected]> --- drivers/block/loop.c | 291 +++++++++++++++++++++------------------------------ 1 file changed, 119 insertions(+), 172 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index d1f168b..68974b2 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -87,28 +87,6 @@ static int part_shift; static struct workqueue_struct *loop_wq; -/* - * Transfer functions - */ -static int transfer_none(struct loop_device *lo, int cmd, - struct page *raw_page, unsigned raw_off, - struct page *loop_page, unsigned loop_off, - int size, sector_t real_block) -{ - char *raw_buf = kmap_atomic(raw_page) + raw_off; - char *loop_buf = kmap_atomic(loop_page) + loop_off; - - if (cmd == READ) - memcpy(loop_buf, raw_buf, size); - else - memcpy(raw_buf, loop_buf, size); - - kunmap_atomic(loop_buf); - kunmap_atomic(raw_buf); - cond_resched(); - return 0; -} - static int transfer_xor(struct loop_device *lo, int cmd, struct page *raw_page, unsigned raw_off, struct page *loop_page, unsigned loop_off, @@ -147,7 +125,6 @@ static int xor_init(struct loop_device *lo, const struct loop_info64 *info) static struct loop_func_table none_funcs = { .number = LO_CRYPT_NONE, - .transfer = transfer_none, }; static struct loop_func_table xor_funcs = { @@ -214,206 +191,169 @@ lo_do_transfer(struct loop_device *lo, int cmd, struct page *lpage, unsigned loffs, int size, sector_t rblock) { - if (unlikely(!lo->transfer)) + int ret; + + ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); + if (likely(!ret)) return 0; - return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); + printk_ratelimited(KERN_ERR + "loop: Transfer error at byte offset %llu, length %i.\n", + (unsigned long long)rblock << 9, size); + return ret; } -/** - * __do_lo_send_write - helper for writing data to a loop device - * - * This helper just factors out common code between do_lo_send_direct_write() - * and do_lo_send_write(). - */ -static int __do_lo_send_write(struct file *file, - u8 *buf, const int len, loff_t pos) +static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos) { + struct iov_iter i; ssize_t bw; - mm_segment_t old_fs = get_fs(); + + iov_iter_bvec(&i, ITER_BVEC, bvec, 1, bvec->bv_len); file_start_write(file); - set_fs(get_ds()); - bw = file->f_op->write(file, buf, len, &pos); - set_fs(old_fs); + bw = vfs_iter_write(file, &i, ppos); file_end_write(file); - if (likely(bw == len)) + + if (likely(bw == bvec->bv_len)) return 0; - printk_ratelimited(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n", - (unsigned long long)pos, len); + + printk_ratelimited(KERN_ERR + "loop: Write error at byte offset %llu, length %i.\n", + (unsigned long long)*ppos, bvec->bv_len); if (bw >= 0) bw = -EIO; return bw; } -/** - * do_lo_send_direct_write - helper for writing data to a loop device - * - * This is the fast, non-transforming version that does not need double - * buffering. - */ -static int do_lo_send_direct_write(struct loop_device *lo, - struct bio_vec *bvec, loff_t pos, struct page *page) +static int lo_write_simple(struct loop_device *lo, struct request *rq, + loff_t pos) { - ssize_t bw = __do_lo_send_write(lo->lo_backing_file, - kmap(bvec->bv_page) + bvec->bv_offset, - bvec->bv_len, pos); - kunmap(bvec->bv_page); - cond_resched(); - return bw; + struct bio_vec bvec; + struct req_iterator iter; + int ret = 0; + + rq_for_each_segment(bvec, rq, iter) { + ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos); + if (ret < 0) + break; + cond_resched(); + } + + return ret; } -/** - * do_lo_send_write - helper for writing data to a loop device - * +/* * This is the slow, transforming version that needs to double buffer the * data as it cannot do the transformations in place without having direct * access to the destination pages of the backing file. */ -static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec, - loff_t pos, struct page *page) -{ - int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page, - bvec->bv_offset, bvec->bv_len, pos >> 9); - if (likely(!ret)) - return __do_lo_send_write(lo->lo_backing_file, - page_address(page), bvec->bv_len, - pos); - printk_ratelimited(KERN_ERR "loop: Transfer error at byte offset %llu, " - "length %i.\n", (unsigned long long)pos, bvec->bv_len); - if (ret > 0) - ret = -EIO; - return ret; -} - -static int lo_send(struct loop_device *lo, struct request *rq, loff_t pos) +static int lo_write_transfer(struct loop_device *lo, struct request *rq, + loff_t pos) { - int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t, - struct page *page); - struct bio_vec bvec; + struct bio_vec bvec, b; struct req_iterator iter; - struct page *page = NULL; + struct page *page; int ret = 0; - if (lo->transfer != transfer_none) { - page = alloc_page(GFP_NOIO | __GFP_HIGHMEM); - if (unlikely(!page)) - goto fail; - kmap(page); - do_lo_send = do_lo_send_write; - } else { - do_lo_send = do_lo_send_direct_write; - } + page = alloc_page(GFP_NOIO); + if (unlikely(!page)) + return -ENOMEM; rq_for_each_segment(bvec, rq, iter) { - ret = do_lo_send(lo, &bvec, pos, page); + ret = lo_do_transfer(lo, WRITE, page, 0, bvec.bv_page, + bvec.bv_offset, bvec.bv_len, pos >> 9); + if (unlikely(ret)) + break; + + b.bv_page = page; + b.bv_offset = 0; + b.bv_len = bvec.bv_len; + ret = lo_write_bvec(lo->lo_backing_file, &b, &pos); if (ret < 0) break; - pos += bvec.bv_len; } - if (page) { - kunmap(page); - __free_page(page); - } -out: + + __free_page(page); return ret; -fail: - printk_ratelimited(KERN_ERR "loop: Failed to allocate temporary page for write.\n"); - ret = -ENOMEM; - goto out; } -struct lo_read_data { - struct loop_device *lo; - struct page *page; - unsigned offset; - int bsize; -}; +static int lo_read_simple(struct loop_device *lo, struct request *rq, + loff_t pos) +{ + struct bio_vec bvec; + struct req_iterator iter; + struct iov_iter i; + ssize_t len; -static int -lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, - struct splice_desc *sd) -{ - struct lo_read_data *p = sd->u.data; - struct loop_device *lo = p->lo; - struct page *page = buf->page; - sector_t IV; - int size; - - IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) + - (buf->offset >> 9); - size = sd->len; - if (size > p->bsize) - size = p->bsize; - - if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) { - printk_ratelimited(KERN_ERR "loop: transfer error block %ld\n", - page->index); - size = -EINVAL; - } + rq_for_each_segment(bvec, rq, iter) { + iov_iter_bvec(&i, ITER_BVEC, &bvec, 1, bvec.bv_len); + len = vfs_iter_read(lo->lo_backing_file, &i, &pos); + if (len < 0) + return len; - flush_dcache_page(p->page); + flush_dcache_page(bvec.bv_page); - if (size > 0) - p->offset += size; + if (len != bvec.bv_len) { + struct bio *bio; - return size; -} + __rq_for_each_bio(bio, rq) + zero_fill_bio(bio); + break; + } + cond_resched(); + } -static int -lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd) -{ - return __splice_from_pipe(pipe, sd, lo_splice_actor); + return 0; } -static ssize_t -do_lo_receive(struct loop_device *lo, - struct bio_vec *bvec, int bsize, loff_t pos) +static int lo_read_transfer(struct loop_device *lo, struct request *rq, + loff_t pos) { - struct lo_read_data cookie; - struct splice_desc sd; - struct file *file; - ssize_t retval; - - cookie.lo = lo; - cookie.page = bvec->bv_page; - cookie.offset = bvec->bv_offset; - cookie.bsize = bsize; + struct bio_vec bvec, b; + struct req_iterator iter; + struct iov_iter i; + struct page *page; + ssize_t len; + int ret = 0; - sd.len = 0; - sd.total_len = bvec->bv_len; - sd.flags = 0; - sd.pos = pos; - sd.u.data = &cookie; + page = alloc_page(GFP_NOIO); + if (unlikely(!page)) + return -ENOMEM; - file = lo->lo_backing_file; - retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor); + rq_for_each_segment(bvec, rq, iter) { + loff_t offset = pos; - return retval; -} + b.bv_page = page; + b.bv_offset = 0; + b.bv_len = bvec.bv_len; -static int -lo_receive(struct loop_device *lo, struct request *rq, int bsize, loff_t pos) -{ - struct bio_vec bvec; - struct req_iterator iter; - ssize_t s; + iov_iter_bvec(&i, ITER_BVEC, &b, 1, b.bv_len); + len = vfs_iter_read(lo->lo_backing_file, &i, &pos); + if (len < 0) { + ret = len; + goto out_free_page; + } - rq_for_each_segment(bvec, rq, iter) { - s = do_lo_receive(lo, &bvec, bsize, pos); - if (s < 0) - return s; + ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page, + bvec.bv_offset, len, offset >> 9); + if (ret) + goto out_free_page; + + flush_dcache_page(bvec.bv_page); - if (s != bvec.bv_len) { + if (len != bvec.bv_len) { struct bio *bio; __rq_for_each_bio(bio, rq) zero_fill_bio(bio); break; } - pos += bvec.bv_len; } - return 0; + + ret = 0; +out_free_page: + __free_page(page); + return ret; } static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos) @@ -462,10 +402,17 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq) ret = lo_req_flush(lo, rq); else if (rq->cmd_flags & REQ_DISCARD) ret = lo_discard(lo, rq, pos); + else if (lo->transfer) + ret = lo_write_transfer(lo, rq, pos); else - ret = lo_send(lo, rq, pos); - } else - ret = lo_receive(lo, rq, lo->lo_blocksize, pos); + ret = lo_write_simple(lo, rq, pos); + + } else { + if (lo->transfer) + ret = lo_read_transfer(lo, rq, pos); + else + ret = lo_read_simple(lo, rq, pos); + } return ret; } @@ -786,7 +733,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, lo->lo_device = bdev; lo->lo_flags = lo_flags; lo->lo_backing_file = file; - lo->transfer = transfer_none; + lo->transfer = NULL; lo->ioctl = NULL; lo->lo_sizelimit = 0; lo->old_gfp_mask = mapping_gfp_mask(mapping); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
