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Message-ID: <20160926071601.GA6352@yuval-lap.Home>
Date: Mon, 26 Sep 2016 10:16:01 +0300
From: Yuval Shaia <yuval.shaia@...cle.com>
To: Adit Ranadive <aditr@...are.com>
Cc: dledford@...hat.com, linux-rdma@...r.kernel.org,
pv-drivers@...are.com, netdev@...r.kernel.org,
linux-pci@...r.kernel.org, jhansen@...are.com, asarwade@...are.com,
georgezhang@...are.com, bryantan@...are.com
Subject: Re: [PATCH v5 08/16] IB/pvrdma: Add device command support
Minor question/suggestion inline.
(sorry for missing it till now).
Yuval
On Sat, Sep 24, 2016 at 04:21:32PM -0700, Adit Ranadive wrote:
> This patch enables posting Verb requests and receiving responses to/from
> the backend PVRDMA emulation layer.
>
> Reviewed-by: Yuval Shaia <yuval.shaia@...cle.com>
> Reviewed-by: Jorgen Hansen <jhansen@...are.com>
> Reviewed-by: George Zhang <georgezhang@...are.com>
> Reviewed-by: Aditya Sarwade <asarwade@...are.com>
> Reviewed-by: Bryan Tan <bryantan@...are.com>
> Signed-off-by: Adit Ranadive <aditr@...are.com>
> ---
> Changes v4->v5:
> - Moved the timeout to pvrdma_cmd_recv.
> - Added additional response code parameter to pvrdma_cmd_post.
>
> Changes v3->v4:
> - Removed the min check and added a BUILD_BUG_ON check for size.
>
> Changes v2->v3:
> - Converted pvrdma_cmd_recv to inline.
> - Added a min check in the memcpy to cmd_slot.
> - Removed the boolean from pvrdma_cmd_post.
> ---
> drivers/infiniband/hw/pvrdma/pvrdma_cmd.c | 117 ++++++++++++++++++++++++++++++
> 1 file changed, 117 insertions(+)
> create mode 100644 drivers/infiniband/hw/pvrdma/pvrdma_cmd.c
>
> diff --git a/drivers/infiniband/hw/pvrdma/pvrdma_cmd.c b/drivers/infiniband/hw/pvrdma/pvrdma_cmd.c
> new file mode 100644
> index 0000000..21f1af8
> --- /dev/null
> +++ b/drivers/infiniband/hw/pvrdma/pvrdma_cmd.c
> @@ -0,0 +1,117 @@
> +/*
> + * Copyright (c) 2012-2016 VMware, Inc. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of EITHER the GNU General Public License
> + * version 2 as published by the Free Software Foundation or the BSD
> + * 2-Clause License. This program is distributed in the hope that it
> + * will be useful, but WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED
> + * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
> + * See the GNU General Public License version 2 for more details at
> + * http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program available in the file COPYING in the main
> + * directory of this source tree.
> + *
> + * The BSD 2-Clause License
> + *
> + * Redistribution and use in source and binary forms, with or
> + * without modification, are permitted provided that the following
> + * conditions are met:
> + *
> + * - Redistributions of source code must retain the above
> + * copyright notice, this list of conditions and the following
> + * disclaimer.
> + *
> + * - Redistributions in binary form must reproduce the above
> + * copyright notice, this list of conditions and the following
> + * disclaimer in the documentation and/or other materials
> + * provided with the distribution.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
> + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
> + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
> + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
> + * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
> + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
> + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
> + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
> + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
> + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
> + * OF THE POSSIBILITY OF SUCH DAMAGE.
> + */
> +
> +#include <linux/list.h>
> +
> +#include "pvrdma.h"
> +
> +#define PVRDMA_CMD_TIMEOUT 10000 /* ms */
> +
> +static inline int pvrdma_cmd_recv(struct pvrdma_dev *dev,
> + union pvrdma_cmd_resp *resp,
> + unsigned resp_code)
> +{
> + int err;
> +
> + dev_dbg(&dev->pdev->dev, "receive response from device\n");
> +
> + err = wait_for_completion_interruptible_timeout(&dev->cmd_done,
> + msecs_to_jiffies(PVRDMA_CMD_TIMEOUT));
> + if (err == 0 || err == -ERESTARTSYS) {
> + dev_warn(&dev->pdev->dev,
> + "completion timeout or interrupted\n");
> + return -ETIMEDOUT;
> + }
> +
> + spin_lock(&dev->cmd_lock);
> + memcpy(resp, dev->resp_slot, sizeof(*resp));
> + spin_unlock(&dev->cmd_lock);
> +
> + if (resp->hdr.ack != resp_code) {
> + dev_warn(&dev->pdev->dev,
> + "unknown response %#x expected %#x\n",
> + resp->hdr.ack, resp_code);
> + return -EFAULT;
> + }
> +
> + return 0;
> +}
> +
> +int
> +pvrdma_cmd_post(struct pvrdma_dev *dev, union pvrdma_cmd_req *req,
> + union pvrdma_cmd_resp *resp, unsigned resp_code)
> +{
> + int err;
> +
> + dev_dbg(&dev->pdev->dev, "post request to device\n");
> +
> + /* Serializiation */
> + down(&dev->cmd_sema);
> +
> + BUILD_BUG_ON(sizeof(union pvrdma_cmd_req) !=
> + sizeof(struct pvrdma_cmd_modify_qp));
> +
> + spin_lock(&dev->cmd_lock);
> + memcpy(dev->cmd_slot, req, sizeof(*req));
> + spin_unlock(&dev->cmd_lock);
> +
> + init_completion(&dev->cmd_done);
> + pvrdma_write_reg(dev, PVRDMA_REG_REQUEST, 0);
> +
> + /* Make sure the request is written before reading status. */
> + mb();
> +
> + err = pvrdma_read_reg(dev, PVRDMA_REG_ERR);
> + if (err == 0) {
> + if (resp != NULL)
> + err = pvrdma_cmd_recv(dev, resp, resp_code);
> + } else {
> + dev_warn(&dev->pdev->dev, "failed to write request %d\n", err);
> + }
Please note that callers checks if err<0 while here err!=0 considered as
error.
Looking at similar code in pvrdma_pci_probe i can see that function
"translates" this error to -EINVAL. Suggesting to do the same here
(although -EINVAL is not a good choice, if device can be more friendly with
the return code then we can propagate it up or just print a suitable error
i.e. EAGAIN or ENOMEM otherwise EFAULT should be sufficient).
> +
> + up(&dev->cmd_sema);
> +
> + return err;
> +}
> --
> 2.7.4
>
> --
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