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Wed, 20 Sep 2023 08:14:54 +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: Wed, 20 Sep 2023 13:37:41 +0530 Message-Id: <20230920080756.11919-5-nj.shetty@samsung.com> In-Reply-To: <20230920080756.11919-1-nj.shetty@samsung.com> MIME-Version: 1.0 X-Brightmail-Tracker: H4sIAAAAAAAAA02Tf1BUVRTHue8tj4Vx7QkoFxppXVNDB1gQtouCOab0AscYoamxjF7sCxjY Zdvlh0QTGGACww9FIhcUVn4JGCghP10kCPnZLOGwGxAQuNsU1CKgZZHSsg/L/8753HPu937P ncPFbbOtnLiR0lhGLqWjBYQNp6nbZZera6MNI+yYxVD9wB0cLT5c4aDP8h7jqHYyl0Dz3UsA 6Ts/B0htLLJEY52tGKqu7cHQ+S4tQIZRJYbU43uQ6kw5B91S93PQ3bZiApVUGqxQlq6FQFW9 TzD0Q54BoBb9aYCaVkpwVDe/wEF948+je1lnAdI87rU86Ei1KietKM3UDQ5197s4qqEmg6C+ Lk+m2sdSCKosJ9+Syk41EtSiYZxDLXSMElROYw2glhucqQb971gQ70SUbwRDixk5n5GGxYgj peF+gsDg0FdDvUVCD1cPH/SygC+lJYyf4PDRIFf/yGjTEAT8eDo6zoSCaIVC4H7AVx4TF8vw I2IUsX4CRiaOlnnJ3BS0RBEnDXeTMrH7PIRCT29T4ftRESMXWzDZyKFT/6zex1LAQ+9MYM2F pBfsa23CMoEN15ZsBzDtGxXOJksAKqu+AmzyB4CPtEOmhGtu0eg+YrkawF/HlJZsko7Bur/u 4WtFBLkHDq5y17g9mYLD6+1l5ptwsgyH6qkSYk3cjkSwp62HsxZzyB1w9sEjM+eR+2Da6ATB qrnD3OlNa9ia3A+Xy3VWbMkm2H9Rb27FyRdg6s0i87MhWWYNF1Q5HNbcYTjUXESwsR2c6220 YmMnuGxUr/MEWH3hKsE2p5k865SAPXgFpg/kmt3gpAusb3Nn8VZYMFCHscIbYfaKHmM5D7Zc fhpvh9fqS9fvd4TaP0+ve6Fg6vWTa9iWzAGwoDYwD/CVz9hRPmNH+b9wKcBrgCMjU0jCGYW3 zFPKJPz3yWExkgZg3ovdAS1g5qf7bl0A44IuALm4wJ4n2WnD2PLEdOLHjDwmVB4XzSi6gLdp 3Odwp81hMabFksaGenj5CL1EIpGXz16Rh8CBN59+SWxLhtOxTBTDyBj50z6Ma+2Ugm3J+vBQ t9pYe8ni3V82Z2w7Wz+dOq7CnYtbNxgr0ex4/HCwJgHuKJxLLrxt99q1oJIQo3iqQqh+rnls +/GhU3E+NXPHfH6rnrmcdPwlQ+mRJeX3YR9EJTpGuwzLLEI6Fasi/7CAI1r7ManEQTPxorXW 3qtixVWgS6JvjPT3hTzRLZ+7KrR4HXv7QOGbJwe3OfpqxBkV/MlPeKrqzDlV4Vnf3s7Z80fn OrbSwY1XNhi+sN1ZP71L+/cilbT3258T7zTOE/Fch5n9+hL61oUz8ZUPnAdvX/myOd+vYMtE /o9OK5qAg+/4l97kit/TO6R6Vn26sUp17A3S8q3kFcNwYLGL+5TuhICjiKA9duNyBf0vqg9d LKAEAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA02Rf0yMcRzHfb/P03PPHdeeruJbJjnKVlOdxHeJEeNZIczMDDl6VHNXuZMf +UOcXbpIQnYdYuXi2o4rUkd2LklIVqs4S4vOr5vqpGIpXLH577XX+/357LN9aEJUS/rSySl7 OUWKVCamBGRlrdhvDjQIuLDGbF9848kjAjsHhkl8NG+EwGUdpyjsqP0KcLclC+CaHp0bfmWp hvh6WR3E+dY2gO2thRDX2ILxFXUJie/VNJC4xXyBwkV6Ow/ntFdRuLR+FOKXeXaAq7qPAFw5 XERgo6OXxI9tU/G7nOMAN43Uuy3xYasLO3hs0xsTybY0prPlhmyKrSg5zN59lUmxxbln3NiT qh6KddptJNt7v5Vic28ZANtf7seWd3+Ba4WbBVEJnCx5H6cIXbxdkNSsrYJpzdEHfv7qg5lg IEIDaBox81BT+x4NENAi5i5A+eespAbw/3gfpB95SIyzJ7o++oE3XlJBVHIxk+capphg9PQX 7fJejIZA2dU9Y8MEYyJQ86P5LvZkMKoz1415kglAb799p1wsZCLRsdbX1PgRoehUp4dL85mF qL+knedi0Z/K0xdFvPG6B2rQdv9dPx2pbuuIPMAU/hcV/hddBtAAfLg0pTxRrpSkzU3h9oco pXJlekpiyM5UeTkY+3NQUBW4Z+gLsQJIAytANCH2EsoDBZxImCA9mMEpUuMV6TJOaQVTaVI8 RTjoOJkgYhKle7ndHJfGKf6lkOb7ZkJjwefwoQcrc4TuHtNO99Wv1Dom2mXq8+4a/vvU5NWS oe9tZt21GY6tk0ofms4Ndgzm2woO/XzuvWvLoC0mQGqOdJh2JMf0vMl16jpVxiO6G8XyyN7Z wKBesKDtcItz0ZUT0OTxoeuqUp+wjnPK7AMxk8LDNvmPBMfGxzYGWEIuwC/+SUMnuiRqL77b xMSGH6ROH1jqfjPes8XbdMlkz0rSRHQu9j499Gw9/PgpLLbggDovzrLOsmbFHX14JZ61MTrq WeV8MwyYE+2tndy8bcK+5cOrskLjjH5nrxa/1C6LuKmSdc14MnP7aEfUNEmj0Z6xdIlzw/61 4v6KhfKCOP8aMalMkkqCCIVS+hta4tVRVgMAAA== X-CMS-MailID: 20230920081458epcas5p3a3e12d8b5661b5d6f4420316630b02e1 X-Msg-Generator: CA X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20230920081458epcas5p3a3e12d8b5661b5d6f4420316630b02e1 References: <20230920080756.11919-1-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 10.11.54.4 Subject: [dm-devel] [PATCH v16 04/12] 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: Anuj Gupta , Vincent Fu , anuj1072538@gmail.com, martin.petersen@oracle.com, linux-scsi@vger.kernel.org, linux-doc@vger.kernel.org, gost.dev@samsung.com, nitheshshetty@gmail.com, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, mcgrof@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 10.11.54.4 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. 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 50d10fa3c4c5..da3594d25a3f 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); @@ -316,6 +330,215 @@ 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_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 5405499bcf22..e0a832a1c3a7 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 */