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Wed, 6 Dec 2023 10:11:18 +0000 (GMT) Received: from epsmgms1p2new.samsung.com (unknown [182.195.42.42]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20231206101118epsmtrp2882cd222b4c8fcca5aaafc6113b65840~eNlwVBeI-0924709247epsmtrp2d; Wed, 6 Dec 2023 10:11:18 +0000 (GMT) X-AuditID: b6c32a4a-261fd70000002719-2d-657048c6a55e Received: from epsmtip2.samsung.com ( [182.195.34.31]) by epsmgms1p2new.samsung.com (Symantec Messaging Gateway) with SMTP id B1.52.08817.6C840756; Wed, 6 Dec 2023 19:11:18 +0900 (KST) Received: from localhost.localdomain (unknown [107.99.41.245]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20231206101113epsmtip278f834a99ee8a24a8447ab449801a2ff~eNlrq_aCz3173831738epsmtip2Z; Wed, 6 Dec 2023 10:11:13 +0000 (GMT) From: Kanchan Joshi To: Jens Axboe , Jonathan Corbet , Alasdair Kergon , Mike Snitzer , Mikulas Patocka , dm-devel@lists.linux.dev, Keith Busch , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , Alexander Viro , Christian Brauner Cc: martin.petersen@oracle.com, linux-scsi@vger.kernel.org, nitheshshetty@gmail.com, anuj1072538@gmail.com, gost.dev@samsung.com, mcgrof@kernel.org, Nitesh Shetty , Vincent Fu , Anuj Gupta , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v18 04/12] block: add emulation for copy Date: Wed, 6 Dec 2023 15:32:36 +0530 Message-Id: <20231206100253.13100-5-joshi.k@samsung.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231206100253.13100-1-joshi.k@samsung.com> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Brightmail-Tracker: H4sIAAAAAAAAA01TbUxTVxjeufdyWyB1bdVxVhOBOtwE+ShruwMDNGLcjWMZC/90k93QO0BK 2/UDYdkyKoJYUPmQAVU+hM4PMDAKQ0C6ACqgC2AkdYMENqSdczAU2TBaYGtp3fz3vM/7PHnf 5z05bJxfzBKw0xVaRq2g5ULSh+i8vuOt0EFKxUQsVryJWm8P4mjxbweBjpas4qh56jSJ5q4/ AcjWdxyg+oYaAk30dWPocvNNDJUN3APIbjViyDIZgs4XmAjUa7lFoPGecySqu2BnoaKfukh0 cWgNQz+X2AEqLbRiqMumB6jTUYejlrlHBBqe3IJmiwoBGlsd8totoLqNUyxqbLqNoMZHdJS5 6QRJtZu+pn5vrwbUtYlckmo8Ve5FncxbIKlF+yRBPfrBSlKnOpoAtWTeSpltf2KJGw5kxKQx tIxRBzCKFKUsXZEaK3w/KTk+WSKNEIWKotA7wgAFncnECvcmJIbuS5c7zyEMyKLlOieVSGs0 wvC4GLVSp2UC0pQabayQUcnkKrEqTENnanSK1DAFo40WRURESpzCTzPS6hqrMdXanmxL/n1W LjBKDcCbDbliOL/8i5cB+LD53GsALhvPeIonABZYbbi7WAYw76aeeGEpMOtJd8MCYGmlwWNZ ArCrfcRpYbNJ7g54p1znMmziXsFhd5vIpcG5jTi0TNeRrsZGLoJPHzSsY4IbBEcfm4ELc5z8 1IkVzD3NH1bffcpyYW9uFCx/0IC7NTx4q9q2vhHu1OR9f3Z9Vcht9oa1fVbcbd4Ln/e3km68 Ef4x1MFyYwFcWrB4+BR4t3rUM0wLZ3v7PXgXzL99ej0M7gzT2hPunrUBnnTYMBcNuRxYWMB3 qwPhdJndy4394EyVyYMpWLFQ6bliMYDHzzjIEuBvfCmC8aUIxv+n1QO8CbzOqDSZqYxGoopU MEf+e9kUZaYZrH+L4P1dYObXx2EDAGODAQDZuHATRz6mZPgcGZ3zBaNWJqt1ckYzACTOG5fi gs0pSue/UmiTReKoCLFUKhVHvS0VCf04c/k1Mj43ldYyGQyjYtQvfBjbW5CLHY7P9x+TJSx8 80zTtnKBlEhHR2iJrmN5WF+/1h7MYz7x0dtO768N510y7Ml6pb9eEDqX/bmpNyZ2vr32K8eq 32vfPjRE51Z999lC/BX7fBnZ+WGsMr21SPXxoUFfwrRdygvPqpq+kR1/x5EjzNiWdMN3URx9 eXem0bYlsOX+q/T0wbOVB3lf6g/HV/GPgn1bI7OuXqo4BoNUVQdsjp6HV01HmH92jdeY69Y4 YY0zm5fj5tFHgiC6z3+4x94zqh191i+dNIRd3B4Xfqhv24xS917WwM4JVsK5D3LLBn8MTmxr M4WcX13xKy66R/NUwbOBLbbfQnz7n79h/QvtfDfmWFKOkNCk0aJgXK2h/wVQ6RsynwQAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA02Ra0hTYRjHe885nh1H2mmWvnnJGhSpNZtEvF3JCDsFUlFGFJRLD2ptc+xo N4000VLzHtROhdes1tVlMq/pLM2oVt4qaRW5sUwst252meUcQd9+PL//8/w/PBQuMhK+VIIy iVUrZXIxKSTq2sWBizoYFbvYZpmKbj7swJHt6y8CHS904OiqqYBEw+12gMytJwAqq7hAoJet 9Ri6cvU+hooN/QBZ+ngMNQ+EoPKsKgI1NXcRqKfhPIlKqy0ClPtcT6JLneMYelFoAajoZB+G 9OZ0gOp+leLoxvAnAj0Y8EODuScBMjo63db4MvW8ScAYX9cQTM/jZEanzSaZ21XHmPe3NYBp fJlGMpX5JW5MXsZHkrFZBgjmU0sfyeTXagHzWTeb0ZlHsM2eO4UrY1l5wgFWHbo6WhhfWqnB VONrDzVnvhOkAX5pDnCnIL0EZunSyRwgpER0I4D8rRuES/jAjP4xgYu94JVxq8AVsgE4ducD ngMoiqSD4NOSZOd8Bq3H4Y/rGZhzAadrcNjdMdngRSP43VpBOpmg58EnozrgZI+JuSn7N+Yq CISa7u+TZe70MlhircCdLJrItKSfIVz56bBLYyZc9wNhxp1zeCGg+f8U/58qA5gWzGJVnCJO wUlVYUr2oISTKbhkZZwkJlGhA5M/Dw7WgybtqMQAMAoYAKRw8QwPuTGRFXnEyg4fYdWJe9TJ cpYzAD+KEPt4fBvOixXRcbIkdj/Lqlj1P4tR7r5pmK+3/4lDl8FyxR/vftHCqI2nPmyTvA2r Dh9ZtY4vmGKd/7AoZWSBnbPSx66fXv5z9OC13AsJbdPW1wfE7mjcG3W47Uv7G+ub2tQAPmlm zM8QB2OXrM8acjQmxUVuN68TzpVL+reeDY2I8equHHmWPX50S4GxIf5Mb2ZDud27q/yden6R dMXrojFoEM/pexXR+nhtVdfgzUf+X03f2jR8AdguLUv1CQ5x643Y5Zmiq0HS81HVOdy2WcYN vSWiVLtJHxSWN9QTXdEb6B8Ejea9LcW7Pod3rrzorcxuytwXWuu+ZIi+Fxm+W5tG2Ui30Rr4 xdOUUnx36uLaOsfg4KbIu9FigouXSYNxNSf7C2PAyuliAwAA X-CMS-MailID: 20231206101118epcas5p1cc77b49dbd8bc1601423d02527b03122 X-Msg-Generator: CA CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20231206101118epcas5p1cc77b49dbd8bc1601423d02527b03122 References: <20231206100253.13100-1-joshi.k@samsung.com> From: Nitesh Shetty 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. At present in kernel user of emulation is 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 05dbe7fa5354..e32e00e4a1eb 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); @@ -319,6 +333,215 @@ 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 + * 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); + 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_for_completion_io(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 e8582a38adb7..9fa1ad68beb5 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 */