--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+#include "kublk.h"
+
+#define NR_STRIPE MAX_BACK_FILES
+
+struct stripe_conf {
+ unsigned nr_files;
+ unsigned shift;
+};
+
+struct stripe {
+ loff_t start;
+ unsigned nr_sects;
+ int seq;
+
+ struct iovec *vec;
+ unsigned nr_vec;
+ unsigned cap;
+};
+
+struct stripe_array {
+ struct stripe s[NR_STRIPE];
+ unsigned nr;
+ struct iovec _vec[];
+};
+
+static inline const struct stripe_conf *get_chunk_shift(const struct ublk_queue *q)
+{
+ return (struct stripe_conf *)q->dev->private_data;
+}
+
+static inline unsigned calculate_nr_vec(const struct stripe_conf *conf,
+ const struct ublksrv_io_desc *iod)
+{
+ const unsigned shift = conf->shift - 9;
+ const unsigned unit_sects = conf->nr_files << shift;
+ loff_t start = iod->start_sector;
+ loff_t end = start + iod->nr_sectors;
+
+ return (end / unit_sects) - (start / unit_sects) + 1;
+}
+
+static struct stripe_array *alloc_stripe_array(const struct stripe_conf *conf,
+ const struct ublksrv_io_desc *iod)
+{
+ unsigned nr_vecs = calculate_nr_vec(conf, iod);
+ unsigned total = nr_vecs * conf->nr_files;
+ struct stripe_array *s;
+ int i;
+
+ s = malloc(sizeof(*s) + total * sizeof(struct iovec));
+
+ s->nr = 0;
+ for (i = 0; i < conf->nr_files; i++) {
+ struct stripe *t = &s->s[i];
+
+ t->nr_vec = 0;
+ t->vec = &s->_vec[i * nr_vecs];
+ t->nr_sects = 0;
+ t->cap = nr_vecs;
+ }
+
+ return s;
+}
+
+static void free_stripe_array(struct stripe_array *s)
+{
+ free(s);
+}
+
+static void calculate_stripe_array(const struct stripe_conf *conf,
+ const struct ublksrv_io_desc *iod, struct stripe_array *s)
+{
+ const unsigned shift = conf->shift - 9;
+ const unsigned chunk_sects = 1 << shift;
+ const unsigned unit_sects = conf->nr_files << shift;
+ off64_t start = iod->start_sector;
+ off64_t end = start + iod->nr_sectors;
+ unsigned long done = 0;
+ unsigned idx = 0;
+
+ while (start < end) {
+ unsigned nr_sects = chunk_sects - (start & (chunk_sects - 1));
+ loff_t unit_off = (start / unit_sects) * unit_sects;
+ unsigned seq = (start - unit_off) >> shift;
+ struct stripe *this = &s->s[idx];
+ loff_t stripe_off = (unit_off / conf->nr_files) +
+ (start & (chunk_sects - 1));
+
+ if (nr_sects > end - start)
+ nr_sects = end - start;
+ if (this->nr_sects == 0) {
+ this->nr_sects = nr_sects;
+ this->start = stripe_off;
+ this->seq = seq;
+ s->nr += 1;
+ } else {
+ assert(seq == this->seq);
+ assert(this->start + this->nr_sects == stripe_off);
+ this->nr_sects += nr_sects;
+ }
+
+ assert(this->nr_vec < this->cap);
+ this->vec[this->nr_vec].iov_base = (void *)(iod->addr + done);
+ this->vec[this->nr_vec++].iov_len = nr_sects << 9;
+
+ start += nr_sects;
+ done += nr_sects << 9;
+ idx = (idx + 1) % conf->nr_files;
+ }
+}
+
+static inline enum io_uring_op stripe_to_uring_op(const struct ublksrv_io_desc *iod)
+{
+ unsigned ublk_op = ublksrv_get_op(iod);
+
+ if (ublk_op == UBLK_IO_OP_READ)
+ return IORING_OP_READV;
+ else if (ublk_op == UBLK_IO_OP_WRITE)
+ return IORING_OP_WRITEV;
+ assert(0);
+}
+
+static int stripe_queue_tgt_rw_io(struct ublk_queue *q, const struct ublksrv_io_desc *iod, int tag)
+{
+ const struct stripe_conf *conf = get_chunk_shift(q);
+ enum io_uring_op op = stripe_to_uring_op(iod);
+ struct io_uring_sqe *sqe[NR_STRIPE];
+ struct stripe_array *s = alloc_stripe_array(conf, iod);
+ struct ublk_io *io = ublk_get_io(q, tag);
+ int i;
+
+ io->private_data = s;
+ calculate_stripe_array(conf, iod, s);
+
+ ublk_queue_alloc_sqes(q, sqe, s->nr);
+ for (i = 0; i < s->nr; i++) {
+ struct stripe *t = &s->s[i];
+
+ io_uring_prep_rw(op, sqe[i],
+ t->seq + 1,
+ (void *)t->vec,
+ t->nr_vec,
+ t->start << 9);
+ io_uring_sqe_set_flags(sqe[i], IOSQE_FIXED_FILE);
+ /* bit63 marks us as tgt io */
+ sqe[i]->user_data = build_user_data(tag, ublksrv_get_op(iod), i, 1);
+ }
+ return s->nr;
+}
+
+static int handle_flush(struct ublk_queue *q, const struct ublksrv_io_desc *iod, int tag)
+{
+ const struct stripe_conf *conf = get_chunk_shift(q);
+ struct io_uring_sqe *sqe[NR_STRIPE];
+ int i;
+
+ ublk_queue_alloc_sqes(q, sqe, conf->nr_files);
+ for (i = 0; i < conf->nr_files; i++) {
+ io_uring_prep_fsync(sqe[i], i + 1, IORING_FSYNC_DATASYNC);
+ io_uring_sqe_set_flags(sqe[i], IOSQE_FIXED_FILE);
+ sqe[i]->user_data = build_user_data(tag, UBLK_IO_OP_FLUSH, 0, 1);
+ }
+ return conf->nr_files;
+}
+
+static int stripe_queue_tgt_io(struct ublk_queue *q, int tag)
+{
+ const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
+ unsigned ublk_op = ublksrv_get_op(iod);
+ int ret = 0;
+
+ switch (ublk_op) {
+ case UBLK_IO_OP_FLUSH:
+ ret = handle_flush(q, iod, tag);
+ break;
+ case UBLK_IO_OP_WRITE_ZEROES:
+ case UBLK_IO_OP_DISCARD:
+ ret = -ENOTSUP;
+ break;
+ case UBLK_IO_OP_READ:
+ case UBLK_IO_OP_WRITE:
+ ret = stripe_queue_tgt_rw_io(q, iod, tag);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ ublk_dbg(UBLK_DBG_IO, "%s: tag %d ublk io %x %llx %u ret %d\n", __func__, tag,
+ iod->op_flags, iod->start_sector, iod->nr_sectors << 9, ret);
+ return ret;
+}
+
+static int ublk_stripe_queue_io(struct ublk_queue *q, int tag)
+{
+ int queued = stripe_queue_tgt_io(q, tag);
+
+ ublk_queued_tgt_io(q, tag, queued);
+ return 0;
+}
+
+static void ublk_stripe_io_done(struct ublk_queue *q, int tag,
+ const struct io_uring_cqe *cqe)
+{
+ const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
+ unsigned op = user_data_to_op(cqe->user_data);
+ struct ublk_io *io = ublk_get_io(q, tag);
+ int res = cqe->res;
+
+ if (res < 0) {
+ if (!io->result)
+ io->result = res;
+ ublk_err("%s: io failure %d tag %u\n", __func__, res, tag);
+ }
+
+ /* fail short READ/WRITE simply */
+ if (op == UBLK_IO_OP_READ || op == UBLK_IO_OP_WRITE) {
+ unsigned seq = user_data_to_tgt_data(cqe->user_data);
+ struct stripe_array *s = io->private_data;
+
+ if (res < s->s[seq].vec->iov_len)
+ io->result = -EIO;
+ }
+
+ if (ublk_completed_tgt_io(q, tag)) {
+ int res = io->result;
+
+ if (!res)
+ res = iod->nr_sectors << 9;
+
+ ublk_complete_io(q, tag, res);
+
+ free_stripe_array(io->private_data);
+ io->private_data = NULL;
+ }
+}
+
+static int ublk_stripe_tgt_init(const struct dev_ctx *ctx, struct ublk_dev *dev)
+{
+ struct ublk_params p = {
+ .types = UBLK_PARAM_TYPE_BASIC,
+ .basic = {
+ .attrs = UBLK_ATTR_VOLATILE_CACHE,
+ .logical_bs_shift = 9,
+ .physical_bs_shift = 12,
+ .io_opt_shift = 12,
+ .io_min_shift = 9,
+ .max_sectors = dev->dev_info.max_io_buf_bytes >> 9,
+ },
+ };
+ unsigned chunk_size = ctx->chunk_size;
+ struct stripe_conf *conf;
+ unsigned chunk_shift;
+ loff_t bytes = 0;
+ int ret, i;
+
+ if ((chunk_size & (chunk_size - 1)) || !chunk_size) {
+ ublk_err("invalid chunk size %u\n", chunk_size);
+ return -EINVAL;
+ }
+
+ if (chunk_size < 4096 || chunk_size > 512 * 1024) {
+ ublk_err("invalid chunk size %u\n", chunk_size);
+ return -EINVAL;
+ }
+
+ chunk_shift = ilog2(chunk_size);
+
+ ret = backing_file_tgt_init(dev);
+ if (ret)
+ return ret;
+
+ if (!dev->tgt.nr_backing_files || dev->tgt.nr_backing_files > NR_STRIPE)
+ return -EINVAL;
+
+ assert(dev->nr_fds == dev->tgt.nr_backing_files + 1);
+
+ for (i = 0; i < dev->tgt.nr_backing_files; i++)
+ dev->tgt.backing_file_size[i] &= ~((1 << chunk_shift) - 1);
+
+ for (i = 0; i < dev->tgt.nr_backing_files; i++) {
+ unsigned long size = dev->tgt.backing_file_size[i];
+
+ if (size != dev->tgt.backing_file_size[0])
+ return -EINVAL;
+ bytes += size;
+ }
+
+ conf = malloc(sizeof(*conf));
+ conf->shift = chunk_shift;
+ conf->nr_files = dev->tgt.nr_backing_files;
+
+ dev->private_data = conf;
+ dev->tgt.dev_size = bytes;
+ p.basic.dev_sectors = bytes >> 9;
+ dev->tgt.params = p;
+ dev->tgt.sq_depth = dev->dev_info.queue_depth * conf->nr_files;
+ dev->tgt.cq_depth = dev->dev_info.queue_depth * conf->nr_files;
+
+ printf("%s: shift %u files %u\n", __func__, conf->shift, conf->nr_files);
+
+ return 0;
+}
+
+static void ublk_stripe_tgt_deinit(struct ublk_dev *dev)
+{
+ free(dev->private_data);
+ backing_file_tgt_deinit(dev);
+}
+
+const struct ublk_tgt_ops stripe_tgt_ops = {
+ .name = "stripe",
+ .init_tgt = ublk_stripe_tgt_init,
+ .deinit_tgt = ublk_stripe_tgt_deinit,
+ .queue_io = ublk_stripe_queue_io,
+ .tgt_io_done = ublk_stripe_io_done,
+};
projects / thirdparty / kernel / linux.git / commitdiff
