For the devices which does not support copy, copy emulation is added. It is required for in-kernel users like fabrics, where file descriptor is not available and hence they can't use copy_file_range. Copy-emulation is implemented by reading from source into memory and writing to the corresponding destination asynchronously. Also emulation is used, if copy offload fails or partially completes. Signed-off-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx> Signed-off-by: Vincent Fu <vincent.fu@xxxxxxxxxxx> Signed-off-by: Anuj Gupta <anuj20.g@xxxxxxxxxxx> --- block/blk-lib.c | 178 ++++++++++++++++++++++++++++++++++++++++- block/blk-map.c | 4 +- include/linux/blkdev.h | 3 + 3 files changed, 182 insertions(+), 3 deletions(-) diff --git a/block/blk-lib.c b/block/blk-lib.c index b8e11997b5bf..99b65af8bfc1 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -300,6 +300,175 @@ static ssize_t __blkdev_copy_offload( return blkdev_copy_wait_completion(cio); } +static void *blkdev_copy_alloc_buf(sector_t req_size, sector_t *alloc_size, + gfp_t gfp_mask) +{ + int min_size = PAGE_SIZE; + void *buf; + + while (req_size >= min_size) { + buf = kvmalloc(req_size, gfp_mask); + if (buf) { + *alloc_size = req_size; + return buf; + } + /* retry half the requested size */ + req_size >>= 1; + } + + return NULL; +} + +static void blkdev_copy_emulate_write_endio(struct bio *bio) +{ + struct copy_ctx *ctx = bio->bi_private; + struct cio *cio = ctx->cio; + sector_t clen; + + if (bio->bi_status) { + clen = (bio->bi_iter.bi_sector << SECTOR_SHIFT) - cio->pos_out; + cio->comp_len = min_t(sector_t, clen, cio->comp_len); + } + kfree(bvec_virt(&bio->bi_io_vec[0])); + bio_map_kern_endio(bio); + kfree(ctx); + if (atomic_dec_and_test(&cio->refcount)) { + if (cio->endio) { + cio->endio(cio->private, cio->comp_len); + kfree(cio); + } else + blk_wake_io_task(cio->waiter); + } +} + +static void blkdev_copy_emulate_read_endio(struct bio *read_bio) +{ + struct copy_ctx *ctx = read_bio->bi_private; + struct cio *cio = ctx->cio; + sector_t clen; + + if (read_bio->bi_status) { + clen = (read_bio->bi_iter.bi_sector << SECTOR_SHIFT) - + cio->pos_in; + cio->comp_len = min_t(sector_t, clen, cio->comp_len); + kfree(bvec_virt(&read_bio->bi_io_vec[0])); + bio_map_kern_endio(read_bio); + kfree(ctx); + + if (atomic_dec_and_test(&cio->refcount)) { + if (cio->endio) { + cio->endio(cio->private, cio->comp_len); + kfree(cio); + } else + blk_wake_io_task(cio->waiter); + } + } + schedule_work(&ctx->dispatch_work); + kfree(read_bio); +} + +/* + * If native copy offload feature is absent, this function tries to emulate, + * by copying data from source to a temporary buffer and from buffer to + * destination device. + * Returns the length of bytes copied or error if encountered + */ +static ssize_t __blkdev_copy_emulate( + struct block_device *bdev_in, loff_t pos_in, + struct block_device *bdev_out, loff_t pos_out, + size_t len, cio_iodone_t endio, void *private, gfp_t gfp_mask) +{ + struct request_queue *in = bdev_get_queue(bdev_in); + struct request_queue *out = bdev_get_queue(bdev_out); + struct bio *read_bio, *write_bio; + void *buf = NULL; + struct copy_ctx *ctx; + struct cio *cio; + sector_t buf_len, req_len, rem = 0; + sector_t max_src_hw_len = min_t(unsigned int, + queue_max_hw_sectors(in), + queue_max_segments(in) << (PAGE_SHIFT - SECTOR_SHIFT)) + << SECTOR_SHIFT; + sector_t max_dst_hw_len = min_t(unsigned int, + queue_max_hw_sectors(out), + queue_max_segments(out) << (PAGE_SHIFT - SECTOR_SHIFT)) + << SECTOR_SHIFT; + sector_t max_hw_len = min_t(unsigned int, + max_src_hw_len, max_dst_hw_len); + + cio = kzalloc(sizeof(struct cio), GFP_KERNEL); + if (!cio) + return -ENOMEM; + atomic_set(&cio->refcount, 0); + cio->pos_in = pos_in; + cio->pos_out = pos_out; + cio->waiter = current; + cio->endio = endio; + cio->private = private; + + for (rem = len; rem > 0; rem -= buf_len) { + req_len = min_t(int, max_hw_len, rem); + + buf = blkdev_copy_alloc_buf(req_len, &buf_len, gfp_mask); + if (!buf) + goto err_alloc_buf; + + ctx = kzalloc(sizeof(struct copy_ctx), gfp_mask); + if (!ctx) + goto err_ctx; + + read_bio = bio_map_kern(in, buf, buf_len, gfp_mask); + if (IS_ERR(read_bio)) + goto err_read_bio; + + write_bio = bio_map_kern(out, buf, buf_len, gfp_mask); + if (IS_ERR(write_bio)) + goto err_write_bio; + + ctx->cio = cio; + ctx->write_bio = write_bio; + INIT_WORK(&ctx->dispatch_work, blkdev_copy_dispatch_work); + + read_bio->bi_iter.bi_sector = pos_in >> SECTOR_SHIFT; + read_bio->bi_iter.bi_size = buf_len; + read_bio->bi_opf = REQ_OP_READ | REQ_SYNC; + bio_set_dev(read_bio, bdev_in); + read_bio->bi_end_io = blkdev_copy_emulate_read_endio; + read_bio->bi_private = ctx; + + write_bio->bi_iter.bi_size = buf_len; + write_bio->bi_opf = REQ_OP_WRITE | REQ_SYNC; + bio_set_dev(write_bio, bdev_out); + write_bio->bi_end_io = blkdev_copy_emulate_write_endio; + write_bio->bi_iter.bi_sector = pos_out >> SECTOR_SHIFT; + write_bio->bi_private = ctx; + + atomic_inc(&cio->refcount); + submit_bio(read_bio); + + pos_in += buf_len; + pos_out += buf_len; + } + + /* Wait for completion of all IO's*/ + return blkdev_copy_wait_completion(cio); + +err_write_bio: + bio_put(read_bio); +err_read_bio: + kfree(ctx); +err_ctx: + kvfree(buf); +err_alloc_buf: + cio->comp_len -= min_t(sector_t, cio->comp_len, len - rem); + if (!atomic_read(&cio->refcount)) { + kfree(cio); + return -ENOMEM; + } + /* Wait for submitted IOs to complete */ + return blkdev_copy_wait_completion(cio); +} + static inline ssize_t blkdev_copy_sanity_check( struct block_device *bdev_in, loff_t pos_in, struct block_device *bdev_out, loff_t pos_out, @@ -350,9 +519,16 @@ ssize_t blkdev_copy_offload( if (ret) return ret; - if (blk_queue_copy(q_in) && blk_queue_copy(q_out)) + if (blk_queue_copy(q_in) && blk_queue_copy(q_out)) { ret = __blkdev_copy_offload(bdev_in, pos_in, bdev_out, pos_out, len, endio, private, gfp_mask); + if (ret < 0) + ret = 0; + } + + if (ret != len) + ret = __blkdev_copy_emulate(bdev_in, pos_in + ret, bdev_out, + pos_out + ret, len - ret, endio, private, gfp_mask); return ret; } diff --git a/block/blk-map.c b/block/blk-map.c index 44d74a30ddac..ceeb70a95fd1 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -363,7 +363,7 @@ static void bio_invalidate_vmalloc_pages(struct bio *bio) #endif } -static void bio_map_kern_endio(struct bio *bio) +void bio_map_kern_endio(struct bio *bio) { bio_invalidate_vmalloc_pages(bio); bio_uninit(bio); @@ -380,7 +380,7 @@ static void bio_map_kern_endio(struct bio *bio) * 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, +struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, gfp_t gfp_mask) { unsigned long kaddr = (unsigned long)data; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 96e986b37a29..69fe977afdc9 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1057,6 +1057,9 @@ ssize_t blkdev_copy_offload( struct block_device *bdev_in, loff_t pos_in, struct block_device *bdev_out, loff_t pos_out, size_t len, cio_iodone_t end_io, void *private, gfp_t gfp_mask); +struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, + gfp_t gfp_mask); +void bio_map_kern_endio(struct bio *bio); #define BLKDEV_ZERO_NOUNMAP (1 << 0) /* do not free blocks */ #define BLKDEV_ZERO_NOFALLBACK (1 << 1) /* don't write explicit zeroes */ -- 2.35.1.500.gb896f729e2