From patchwork Fri Jan 30 08:12:30 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Nicholas A. 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[67.23.28.174]) by mx.google.com with ESMTPSA id l3sm5046132obx.14.2015.01.30.00.45.33 (version=TLSv1 cipher=RC4-SHA bits=128/128); Fri, 30 Jan 2015 00:45:33 -0800 (PST) From: "Nicholas A. Bellinger" To: target-devel Cc: linux-scsi , kvm-devel , Paolo Bonzini , "Michael S. Tsirkin" , Nicholas Bellinger Subject: [PATCH 6/8] vhost/scsi: Add ANY_LAYOUT prerequisites Date: Fri, 30 Jan 2015 08:12:30 +0000 Message-Id: <1422605552-24797-7-git-send-email-nab@daterainc.com> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1422605552-24797-1-git-send-email-nab@daterainc.com> References: <1422605552-24797-1-git-send-email-nab@daterainc.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Nicholas Bellinger This patch adds ANY_LAYOUT prerequisites logic for accepting a set of protection + data payloads via iovec + offset. Also includes helpers for calcuating SGLs + invoking vhost_scsi_map_to_sgl() with a known number of iovecs. Required by ANY_LAYOUT processing when struct iovec may be offset into the first outgoing virtio-scsi request header. Cc: Michael S. Tsirkin Cc: Paolo Bonzini Signed-off-by: Nicholas Bellinger --- drivers/vhost/scsi.c | 105 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 105 insertions(+) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 756a893..d2208a41 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -909,6 +909,111 @@ vhost_scsi_map_iov_to_prot(struct tcm_vhost_cmd *cmd, return 0; } +static int +vhost_scsi_calc_sgls(struct iovec *iov, size_t off, size_t bytes, + int *niov, int max_sgls) +{ + size_t tmp = 0; + int sgl_count = 0; + + *niov = 0; + + while (tmp < bytes) { + void __user *base = iov[*niov].iov_base + off; + size_t len = iov[(*niov)++].iov_len - off; + + sgl_count += iov_num_pages(base, len); + tmp += min(len, bytes); + off = 0; + } + 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 -ENOBUFS; + } + return sgl_count; +} + +static int +vhost_scsi_iov_to_sgl(struct tcm_vhost_cmd *cmd, bool write, + struct iovec *iov, size_t iov_off, int niov, + struct scatterlist *sg, int sg_count) +{ + int i, ret; + + for (i = 0; i < niov; i++) { + void __user *base = iov[i].iov_base + iov_off; + size_t len = iov[i].iov_len - iov_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; + iov_off = 0; + } + return 0; +} + +static int +vhost_scsi_mapal(struct tcm_vhost_cmd *cmd, + size_t prot_bytes, struct iovec *prot_iov, size_t prot_off, + size_t data_bytes, struct iovec *data_iov, size_t data_off) +{ + int data_sgl_count = 0, niov, ret; + bool write = (cmd->tvc_data_direction == DMA_FROM_DEVICE); + + if (prot_bytes) { + int prot_sgl_count; + + if (!prot_iov) { + pr_err("%s: prot_iov is NULL, but prot_bytes: %zu" + "present\n", __func__, prot_bytes); + return -EINVAL; + } + prot_sgl_count = vhost_scsi_calc_sgls(prot_iov, prot_off, + prot_bytes, &niov, + TCM_VHOST_PREALLOC_PROT_SGLS); + if (prot_sgl_count < 0) + return prot_sgl_count; + + sg_init_table(cmd->tvc_prot_sgl, prot_sgl_count); + cmd->tvc_prot_sgl_count = prot_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_iov, prot_off, + niov, cmd->tvc_prot_sgl, + prot_sgl_count); + if (ret < 0) { + cmd->tvc_prot_sgl_count = 0; + return ret; + } + } + if (!data_iov) { + pr_err("%s: data_iov is NULL, but data_bytes: %zu present\n", + __func__, data_bytes); + return -EINVAL; + } + data_sgl_count = vhost_scsi_calc_sgls(data_iov, data_off, data_bytes, + &niov, TCM_VHOST_PREALLOC_SGLS); + if (data_sgl_count < 0) + return data_sgl_count; + + sg_init_table(cmd->tvc_sgl, data_sgl_count); + cmd->tvc_sgl_count = data_sgl_count; + pr_debug("%s data_sg %p data_sgl_count %u\n", __func__, + cmd->tvc_sgl, cmd->tvc_sgl_count); + + return vhost_scsi_iov_to_sgl(cmd, write, data_iov, data_off, + niov, cmd->tvc_sgl, data_sgl_count); +} + static void tcm_vhost_submission_work(struct work_struct *work) { struct tcm_vhost_cmd *cmd =