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Fri, 11 Aug 2023 10:57:05 +0000 (GMT) From: Nitesh Shetty To: Jens Axboe , Jonathan Corbet , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, Keith Busch , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , Alexander Viro , Christian Brauner Date: Fri, 11 Aug 2023 16:22:47 +0530 Message-Id: <20230811105300.15889-5-nj.shetty@samsung.com> In-Reply-To: <20230811105300.15889-1-nj.shetty@samsung.com> MIME-Version: 1.0 X-Brightmail-Tracker: H4sIAAAAAAAAA02Te0xTVxzHc+5tL8WteikQDhi37hrjgPAotvWgMJfB9CaajcxtOp1gQy+P Udqmlwq6JfIcroSHVDIoMnAw5DUe5REediBEXgZ1EhDYRKewyZD3mDjDHOWK87/P73t+75Of ABetEi6CSHUMo1MrVBSxidfU5erqEeY8rPROaJWjmv5uHCVmreKo8m4mgaa7FgGa6EgF6H77 PmSZzeej0Y4WDJVXXsNQducwQJNDJgxZxtzRpa9LeOiKpY+HBlsvEqiwdNIGXe75F0MjWZMA NT0rxFH19BwP9Y5tRQ/TzgF0c7WH/64TfXO8jkcPDuhpc8U3BF1fcpZuG40n6OIMI59OT5ol 6IXJMR4999MQQWc0VAB6yfwGbZ6YwYJePxblF8EolIxOzKhDNcpIdbg/dfBwSECITO4t8ZD4 ot2UWK2IZvypwENBHvsjVWtDU+JTCpV+TQpSsCzl9Y6fTqOPYcQRGjbGn2K0SpVWqvVkFdGs Xh3uqWZi9ki8vX1ka44noyK+bf0N11YHxM3XzePx4KrcAGwFkJTCoZVGvgFsEojIKwAu5TwG nLEI4PfdBfyXRleugb8Rkr/y1MbKIrIFwOoZd84pBYPF58YJAxAICNIdXn8usOoOZDwOa9uK 19Pi5BQGh0d/AVYnexLBvwbirIl45A5oHK9bl4XkHng9x9eKkPSCmffsrB625F44Z75NWFlI 2sG+vAmelXHyTZjUmI9zrWXawirDdo4DoaW3ncexPfyzp8GGYxe4NGshOI6F5RfKCGtnkEwG 0HTHBLiHfTClPxO39oCTrrCm1YuTt8Gc/mqMq7sZpj+bwDhdCJu/2+DtsKqm6EV+Zzj8JOEF 03CkpBDnVpUBYGNqE5EFxKZX5jG9Mo/p/9JFAK8ALoyWjQ5nQmVaiYeaiX35yaGaaDNYvwO3 oGZQWbvq2QkwAegEUIBTDkL/w7eVIqFScfoMo9OE6PQqhu0EsrV9n8ddHEM1a4ekjgmRSH29 pXK5XOq7Sy6hnITTKQVKERmuiGGiGEbL6DbiMIGtSzxW/4HP3ZqV6TlZrO1uSdnRAMcd7NyJ EyGHjoQtLKQ7597flTyR6BYr+wMcXN7Zt63tTNHTA5a65pGHcV0+E+KCRrtg8HkQ8mtbvHT+ /c3Rpddyng8ZP9F89J5U/k9eae7xnR9nR/5qmBrUJ3Q/2Pppu/3ftb0qUfLPXsGPA9mlvaUD ea130pKC6z/0ORl8eov92Yu6DodEqvZyVvmtC/QNPyz+kTFnMY16zTGgc3l5YNhcG9x5Sn2V XP2xoest9vctdQ/0uYqyrONP8sO+0u5/JLEr/GIhysnL1Hgk2Xa+6ti9Fg+l+2eVQmHbl2W3 6KlUaYPe+ANpCmBvuPtL+7JnjEeptw9QPDZCIXHDdaziP/1oRyGQBAAA X-Brightmail-Tracker: H4sIAAAAAAAAA02ReUiTcRjH+73v6+vravC6pv08SFyJlaQZHT/tsLuXooMiOqBjtbcZeaxN xYpqaFpbmdIqc+sSZZGGtmkrLWveeSEpmo7UWS4pzzwqy2W9SeB/n+f7/fDwwEPhghzCnToR EcXKI8RhIpJHmEpFXgudhM2SRaN6N5RbXYGjuBQ7jrLbkknUUzoEUJf5EkDW1yGoqF/ngFrN BRh6lF2OoeslzQDZmrQYKrL4ofTETAK9LKoiUGPhHRLd19sc0cPK3xhqSbEBZPp1H0c5PQME emPxQB+vXAao3l7psGYWU99uIJjGumjGmKUimbzMC8yLViXJZFzTODBJ8f0k89VmIZiBV00k cy0/CzDDxtmMsasP2znjAG+lhA07EcPKA1Yf4YWmFnbispz1sYOGQVwJipepgRMF6SVQ92PM kWMB/QzA3NeHJnM3qLeX4ZM8Ez763f3X4f114jH4NrGdVAOKImk/WDNBcbmQVuNQVdBPcANO j2KwVa39J82kERypi+UWEbQP1LQbABfz6WBYczOIQ0gHwOQOZ85wolfAAWMDOXlOMBzUFwOO +bQzrErrIjjGaS8Y/1SHpwBaO6XSTqkeACwLuLAyRbg0/Jgs0F8hDldER0j9j0WGG8G/ly7Y 9Rzoc+3+JQCjQAmAFC4S8lftbpAI+BLx6TOsPPKwPDqMVZQAD4oQzeLPCVNJBLRUHMWeZFkZ K//fYpSTuxLb3di5IeEoO5wwNzrRu+tBzHiD9/D5WlZD2240KdWshTrMasYTn1pv3/LwmdCe Tk1PDhTw1DrVWYmwzzBWbr0qUSV14MzSnwlyl4jvspjqnLYvZOoT8Xu/UK/P9dvGcaYp+Enr 9s1lccq1ysx1x88pPE7tyxiy5oJYa3maum7xhzWXI291PPYMyc//FmTxyd/RvOlewSeH7JUH 57e80/R1O07La97Kcx2ZYxr2XD3+uKqwd2OC2WpxDlno62o3FVXjpi21LotirrZUHHF7uzzK nF6WNbp/aA85z2WnoVp6cW+PdOgZ9F5ivZ73vfdhaKE9bdr0Fb46YUrHXfNI9s0oEaEIFQcu wOUK8R8sKNEjQQMAAA== X-CMS-MailID: 20230811105713epcas5p3b5323a0c553006e60671dde6c72fc4c6 X-Msg-Generator: CA X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20230811105713epcas5p3b5323a0c553006e60671dde6c72fc4c6 References: <20230811105300.15889-1-nj.shetty@samsung.com> X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Subject: [dm-devel] [PATCH v14 04/11] block: add emulation for copy X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Vincent Fu , martin.petersen@oracle.com, linux-doc@vger.kernel.org, gost.dev@samsung.com, Anuj Gupta , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, mcgrof@kernel.org, dlemoal@kernel.org, linux-fsdevel@vger.kernel.org, Nitesh Shetty Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: samsung.com 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. Also emulation can be used, if copy offload fails or partially completes. At present in kernel user of emulation is NVMe fabrics. Signed-off-by: Nitesh Shetty Signed-off-by: Vincent Fu Signed-off-by: Anuj Gupta --- block/blk-lib.c | 223 +++++++++++++++++++++++++++++++++++++++++ include/linux/blkdev.h | 4 + 2 files changed, 227 insertions(+) diff --git a/block/blk-lib.c b/block/blk-lib.c index ad512293730b..5eeb5af20a9a 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -26,6 +26,20 @@ struct blkdev_copy_offload_io { loff_t offset; }; +/* Keeps track of single outstanding copy emulation IO */ +struct blkdev_copy_emulation_io { + struct blkdev_copy_io *cio; + struct work_struct emulation_work; + void *buf; + ssize_t buf_len; + loff_t pos_in; + loff_t pos_out; + ssize_t len; + struct block_device *bdev_in; + struct block_device *bdev_out; + gfp_t gfp; +}; + static sector_t bio_discard_limit(struct block_device *bdev, sector_t sector) { unsigned int discard_granularity = bdev_discard_granularity(bdev); @@ -311,6 +325,215 @@ ssize_t blkdev_copy_offload(struct block_device *bdev, loff_t pos_in, } EXPORT_SYMBOL_GPL(blkdev_copy_offload); +static void *blkdev_copy_alloc_buf(ssize_t req_size, ssize_t *alloc_size, + gfp_t gfp) +{ + int min_size = PAGE_SIZE; + char *buf; + + while (req_size >= min_size) { + buf = kvmalloc(req_size, gfp); + if (buf) { + *alloc_size = req_size; + return buf; + } + req_size >>= 1; + } + + return NULL; +} + +static struct bio *bio_map_buf(void *data, unsigned int len, gfp_t gfp) +{ + 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(nr_pages, gfp); + if (!bio) + return ERR_PTR(-ENOMEM); + bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, 0); + + 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_page(bio, page, bytes, offset) < bytes) { + /* we don't support partial mappings */ + bio_uninit(bio); + kfree(bio); + return ERR_PTR(-EINVAL); + } + + data += bytes; + len -= bytes; + offset = 0; + } + + return bio; +} + +static void blkdev_copy_emulation_work(struct work_struct *work) +{ + struct blkdev_copy_emulation_io *emulation_io = container_of(work, + struct blkdev_copy_emulation_io, emulation_work); + struct blkdev_copy_io *cio = emulation_io->cio; + struct bio *read_bio, *write_bio; + loff_t pos_in = emulation_io->pos_in, pos_out = emulation_io->pos_out; + ssize_t rem, chunk; + int ret = 0; + + for (rem = emulation_io->len; rem > 0; rem -= chunk) { + chunk = min_t(int, emulation_io->buf_len, rem); + + read_bio = bio_map_buf(emulation_io->buf, + emulation_io->buf_len, + emulation_io->gfp); + if (IS_ERR(read_bio)) { + ret = PTR_ERR(read_bio); + break; + } + read_bio->bi_opf = REQ_OP_READ | REQ_SYNC; + bio_set_dev(read_bio, emulation_io->bdev_in); + read_bio->bi_iter.bi_sector = pos_in >> SECTOR_SHIFT; + read_bio->bi_iter.bi_size = chunk; + ret = submit_bio_wait(read_bio); + kfree(read_bio); + if (ret) + break; + + write_bio = bio_map_buf(emulation_io->buf, + emulation_io->buf_len, + emulation_io->gfp); + if (IS_ERR(write_bio)) { + ret = PTR_ERR(write_bio); + break; + } + write_bio->bi_opf = REQ_OP_WRITE | REQ_SYNC; + bio_set_dev(write_bio, emulation_io->bdev_out); + write_bio->bi_iter.bi_sector = pos_out >> SECTOR_SHIFT; + write_bio->bi_iter.bi_size = chunk; + ret = submit_bio_wait(write_bio); + kfree(write_bio); + if (ret) + break; + + pos_in += chunk; + pos_out += chunk; + } + cio->status = ret; + kvfree(emulation_io->buf); + kfree(emulation_io); + blkdev_copy_endio(cio); +} + +static inline ssize_t queue_max_hw_bytes(struct request_queue *q) +{ + return min_t(ssize_t, queue_max_hw_sectors(q) << SECTOR_SHIFT, + queue_max_segments(q) << PAGE_SHIFT); +} +/* + * @bdev_in: source block device + * @pos_in: source offset + * @bdev_out: destination block device + * @pos_out: destination offset + * @len: length in bytes to be copied + * @endio: endio function to be called on completion of copy operation, + * for synchronous operation this should be NULL + * @private: endio function will be called with this private data, + * for synchronous operation this should be NULL + * @gfp_mask: memory allocation flags (for bio_alloc) + * + * For synchronous operation returns the length of bytes copied or error + * For asynchronous operation returns -EIOCBQUEUED or error + * + * Description: + * If native copy offload feature is absent, caller can use this function + * as fallback to perform copy. + * We store information required to perform the copy along with temporary + * buffer allocation. We async punt copy emulation to a worker. And worker + * performs copy in 2 steps. + * 1. Read data from source to temporary buffer + * 2. Write data to destination from temporary buffer + */ +ssize_t blkdev_copy_emulation(struct block_device *bdev_in, loff_t pos_in, + struct block_device *bdev_out, loff_t pos_out, + size_t len, void (*endio)(void *, int, ssize_t), + void *private, gfp_t gfp) +{ + struct request_queue *in = bdev_get_queue(bdev_in); + struct request_queue *out = bdev_get_queue(bdev_out); + struct blkdev_copy_emulation_io *emulation_io; + struct blkdev_copy_io *cio; + ssize_t ret; + size_t max_hw_bytes = min(queue_max_hw_bytes(in), + queue_max_hw_bytes(out)); + + ret = blkdev_copy_sanity_check(bdev_in, pos_in, bdev_out, pos_out, len); + if (ret) + return ret; + + cio = kzalloc(sizeof(*cio), GFP_KERNEL); + if (!cio) + return -ENOMEM; + + cio->waiter = current; + cio->copied = len; + cio->endio = endio; + cio->private = private; + + emulation_io = kzalloc(sizeof(*emulation_io), gfp); + if (!emulation_io) + goto err_free_cio; + emulation_io->cio = cio; + INIT_WORK(&emulation_io->emulation_work, blkdev_copy_emulation_work); + emulation_io->pos_in = pos_in; + emulation_io->pos_out = pos_out; + emulation_io->len = len; + emulation_io->bdev_in = bdev_in; + emulation_io->bdev_out = bdev_out; + emulation_io->gfp = gfp; + + emulation_io->buf = blkdev_copy_alloc_buf(min(max_hw_bytes, len), + &emulation_io->buf_len, gfp); + if (!emulation_io->buf) + goto err_free_emulation_io; + + schedule_work(&emulation_io->emulation_work); + + if (cio->endio) + return -EIOCBQUEUED; + + return blkdev_copy_wait_io_completion(cio); + +err_free_emulation_io: + kfree(emulation_io); +err_free_cio: + kfree(cio); + return -ENOMEM; +} +EXPORT_SYMBOL_GPL(blkdev_copy_emulation); + static int __blkdev_issue_write_zeroes(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask, struct bio **biop, unsigned flags) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 81558cb7c019..67eab354592c 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1046,6 +1046,10 @@ ssize_t blkdev_copy_offload(struct block_device *bdev, loff_t pos_in, loff_t pos_out, size_t len, void (*endio)(void *, int, ssize_t), void *private, gfp_t gfp_mask); +ssize_t blkdev_copy_emulation(struct block_device *bdev_in, loff_t pos_in, + struct block_device *bdev_out, loff_t pos_out, + size_t len, void (*endio)(void *, int, ssize_t), + void *private, gfp_t gfp); #define BLKDEV_ZERO_NOUNMAP (1 << 0) /* do not free blocks */ #define BLKDEV_ZERO_NOFALLBACK (1 << 1) /* don't write explicit zeroes */