diff options
| -rw-r--r-- | drivers/vhost/scsi.c | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index b9800c7a1d5d..5396b8a3028f 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -914,6 +914,99 @@ vhost_scsi_map_iov_to_prot(struct tcm_vhost_cmd *cmd, return 0; } +static int +vhost_scsi_calc_sgls(struct iov_iter *iter, size_t bytes, int max_sgls) +{ + int sgl_count = 0; + + if (!iter || !iter->iov) { + pr_err("%s: iter->iov is NULL, but expected bytes: %zu" + " present\n", __func__, bytes); + return -EINVAL; + } + + sgl_count = iov_iter_npages(iter, 0xffff); + if (sgl_count > max_sgls) { + pr_err("%s: requested sgl_count: %d exceeds pre-allocated" + " max_sgls: %d\n", __func__, sgl_count, max_sgls); + return -EINVAL; + } + return sgl_count; +} + +static int +vhost_scsi_iov_to_sgl(struct tcm_vhost_cmd *cmd, bool write, + struct iov_iter *iter, struct scatterlist *sg, + int sg_count) +{ + size_t off = iter->iov_offset; + int i, ret; + + for (i = 0; i < iter->nr_segs; i++) { + void __user *base = iter->iov[i].iov_base + off; + size_t len = iter->iov[i].iov_len - off; + + ret = vhost_scsi_map_to_sgl(cmd, base, len, sg, write); + if (ret < 0) { + for (i = 0; i < sg_count; i++) { + struct page *page = sg_page(&sg[i]); + if (page) + put_page(page); + } + return ret; + } + sg += ret; + off = 0; + } + return 0; +} + +static int +vhost_scsi_mapal(struct tcm_vhost_cmd *cmd, + size_t prot_bytes, struct iov_iter *prot_iter, + size_t data_bytes, struct iov_iter *data_iter) +{ + int sgl_count, ret; + bool write = (cmd->tvc_data_direction == DMA_FROM_DEVICE); + + if (prot_bytes) { + sgl_count = vhost_scsi_calc_sgls(prot_iter, prot_bytes, + TCM_VHOST_PREALLOC_PROT_SGLS); + if (sgl_count < 0) + return sgl_count; + + sg_init_table(cmd->tvc_prot_sgl, sgl_count); + cmd->tvc_prot_sgl_count = sgl_count; + pr_debug("%s prot_sg %p prot_sgl_count %u\n", __func__, + cmd->tvc_prot_sgl, cmd->tvc_prot_sgl_count); + + ret = vhost_scsi_iov_to_sgl(cmd, write, prot_iter, + cmd->tvc_prot_sgl, + cmd->tvc_prot_sgl_count); + if (ret < 0) { + cmd->tvc_prot_sgl_count = 0; + return ret; + } + } + sgl_count = vhost_scsi_calc_sgls(data_iter, data_bytes, + TCM_VHOST_PREALLOC_SGLS); + if (sgl_count < 0) + return sgl_count; + + sg_init_table(cmd->tvc_sgl, sgl_count); + cmd->tvc_sgl_count = sgl_count; + pr_debug("%s data_sg %p data_sgl_count %u\n", __func__, + cmd->tvc_sgl, cmd->tvc_sgl_count); + + ret = vhost_scsi_iov_to_sgl(cmd, write, data_iter, + cmd->tvc_sgl, cmd->tvc_sgl_count); + if (ret < 0) { + cmd->tvc_sgl_count = 0; + return ret; + } + return 0; +} + static void tcm_vhost_submission_work(struct work_struct *work) { struct tcm_vhost_cmd *cmd = |