Subject: Re: [PATCH v5 02/16] IB/pvrdma: Add user-level shared functions

From: Leon Romanovsky <[email-masked]>
Date: Sun, 25 Sep 2016 10:26:24 +0300

On Sat, Sep 24, 2016 at 04:21:26PM -0700, Adit Ranadive wrote:
> We share some common structures with the user-level driver. This patch adds
> those structures and shared functions to traverse the QP/CQ rings.
>
> Reviewed-by: Yuval Shaia <[email-masked]>
> Reviewed-by: Jorgen Hansen <[email-masked]>
> Reviewed-by: George Zhang <[email-masked]>
> Reviewed-by: Aditya Sarwade <[email-masked]>
> Reviewed-by: Bryan Tan <[email-masked]>
> Signed-off-by: Adit Ranadive <[email-masked]>
> ---
> Changes v4->v5:
>  - Moved pvrdma_uapi.h and pvrdma_user.h into common UAPI folder.
>  - Renamed to pvrdma-uapi.h and pvrdma-abi.h respectively.
>  - Prefixed unsigned vars with __.
>
> Changes v3->v4:
>  - Moved pvrdma_sge into pvrdma_uapi.h
> ---
>  include/uapi/rdma/Kbuild        |   2 +
>  include/uapi/rdma/pvrdma-abi.h  |  99 ++++++++++++++++
>  include/uapi/rdma/pvrdma-uapi.h | 255 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 356 insertions(+)
>  create mode 100644 include/uapi/rdma/pvrdma-abi.h
>  create mode 100644 include/uapi/rdma/pvrdma-uapi.h
>
> diff --git a/include/uapi/rdma/Kbuild b/include/uapi/rdma/Kbuild
> index 4edb0f2..fc2b285 100644
> --- a/include/uapi/rdma/Kbuild
> +++ b/include/uapi/rdma/Kbuild
> @@ -7,3 +7,5 @@ header-y += rdma_netlink.h
>  header-y += rdma_user_cm.h
>  header-y += hfi/
>  header-y += rdma_user_rxe.h
> +header-y += pvrdma-abi.h
> +header-y += pvrdma-uapi.h
> diff --git a/include/uapi/rdma/pvrdma-abi.h b/include/uapi/rdma/pvrdma-abi.h
> new file mode 100644
> index 0000000..6fa0ab6
> --- /dev/null
> +++ b/include/uapi/rdma/pvrdma-abi.h
> @@ -0,0 +1,99 @@
> +/*
> + * 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.
> + */
> +
> +#ifndef __PVRDMA_USER_H__
> +#define __PVRDMA_USER_H__
> +
> +#include <linux/types.h>
> +
> +#define PVRDMA_UVERBS_ABI_VERSION	3
> +#define PVRDMA_BOARD_ID			1
> +#define PVRDMA_REV_ID			1

Please don't add defines which you are not using in the library and the
two above are not in use.

> +
> +struct pvrdma_alloc_ucontext_resp {
> +	__u32 qp_tab_size;
> +	__u32 reserved;
> +};
> +
> +struct pvrdma_alloc_pd_resp {
> +	__u32 pdn;
> +	__u32 reserved;
> +};
> +
> +struct pvrdma_create_cq {
> +	__u64 buf_addr;
> +	__u32 buf_size;
> +	__u32 reserved;
> +};
> +
> +struct pvrdma_create_cq_resp {
> +	__u32 cqn;
> +	__u32 reserved;
> +};
> +
> +struct pvrdma_resize_cq {
> +	__u64 buf_addr;
> +	__u32 buf_size;
> +	__u32 reserved;
> +};
> +
> +struct pvrdma_create_srq {
> +	__u64 buf_addr;
> +};
> +
> +struct pvrdma_create_srq_resp {
> +	__u32 srqn;
> +	__u32 reserved;
> +};
> +
> +struct pvrdma_create_qp {
> +	__u64 rbuf_addr;
> +	__u64 sbuf_addr;
> +	__u32 rbuf_size;
> +	__u32 sbuf_size;
> +	__u64 qp_addr;
> +};
> +
> +#endif /* __PVRDMA_USER_H__ */
> diff --git a/include/uapi/rdma/pvrdma-uapi.h b/include/uapi/rdma/pvrdma-uapi.h
> new file mode 100644
> index 0000000..430d8a5
> --- /dev/null
> +++ b/include/uapi/rdma/pvrdma-uapi.h
> @@ -0,0 +1,255 @@
> +/*
> + * 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.
> + */
> +
> +#ifndef __PVRDMA_UAPI_H__
> +#define __PVRDMA_UAPI_H__
> +
> +#include <linux/types.h>
> +
> +#define PVRDMA_VERSION 17

What do you plan to do with this VERSION?
How is it related to ABI?

> +
> +#define PVRDMA_UAR_HANDLE_MASK	0x00FFFFFF	/* Bottom 24 bits. */
> +#define PVRDMA_UAR_QP_OFFSET	0		/* Offset of QP doorbell. */
> +#define PVRDMA_UAR_QP_SEND	BIT(30)		/* Send bit. */
> +#define PVRDMA_UAR_QP_RECV	BIT(31)		/* Recv bit. */
> +#define PVRDMA_UAR_CQ_OFFSET	4		/* Offset of CQ doorbell. */
> +#define PVRDMA_UAR_CQ_ARM_SOL	BIT(29)		/* Arm solicited bit. */
> +#define PVRDMA_UAR_CQ_ARM	BIT(30)		/* Arm bit. */
> +#define PVRDMA_UAR_CQ_POLL	BIT(31)		/* Poll bit. */
> +#define PVRDMA_INVALID_IDX	-1		/* Invalid index. */

> +
> +/* PVRDMA atomic compare and swap */
> +struct pvrdma_exp_cmp_swap {

_EXP_ looks very similar to MLNX_OFED naming convention.

> +	__u64 swap_val;
> +	__u64 compare_val;
> +	__u64 swap_mask;
> +	__u64 compare_mask;
> +};
> +
> +/* PVRDMA atomic fetch and add */
> +struct pvrdma_exp_fetch_add {

The same as above.

> +	__u64 add_val;
> +	__u64 field_boundary;
> +};
> +
> +/* PVRDMA address vector. */
> +struct pvrdma_av {
> +	__u32 port_pd;
> +	__u32 sl_tclass_flowlabel;
> +	__u8 dgid[16];
> +	__u8 src_path_bits;
> +	__u8 gid_index;
> +	__u8 stat_rate;
> +	__u8 hop_limit;
> +	__u8 dmac[6];
> +	__u8 reserved[6];
> +};
> +
> +/* PVRDMA scatter/gather entry */
> +struct pvrdma_sge {
> +	__u64   addr;
> +	__u32   length;
> +	__u32   lkey;
> +};
> +
> +/* PVRDMA receive queue work request */
> +struct pvrdma_rq_wqe_hdr {
> +	__u64 wr_id;		/* wr id */
> +	__u32 num_sge;		/* size of s/g array */
> +	__u32 total_len;	/* reserved */
> +};
> +/* Use pvrdma_sge (ib_sge) for receive queue s/g array elements. */
> +
> +/* PVRDMA send queue work request */
> +struct pvrdma_sq_wqe_hdr {
> +	__u64 wr_id;		/* wr id */
> +	__u32 num_sge;		/* size of s/g array */
> +	__u32 total_len;	/* reserved */
> +	__u32 opcode;		/* operation type */
> +	__u32 send_flags;	/* wr flags */
> +	union {
> +		__u32 imm_data;
> +		__u32 invalidate_rkey;
> +	} ex;
> +	__u32 reserved;
> +	union {
> +		struct {
> +			__u64 remote_addr;
> +			__u32 rkey;
> +			__u8 reserved[4];
> +		} rdma;
> +		struct {
> +			__u64 remote_addr;
> +			__u64 compare_add;
> +			__u64 swap;
> +			__u32 rkey;
> +			__u32 reserved;
> +		} atomic;
> +		struct {
> +			__u64 remote_addr;
> +			__u32 log_arg_sz;
> +			__u32 rkey;
> +			union {
> +				struct pvrdma_exp_cmp_swap  cmp_swap;
> +				struct pvrdma_exp_fetch_add fetch_add;
> +			} wr_data;
> +		} masked_atomics;
> +		struct {
> +			__u64 iova_start;
> +			__u64 pl_pdir_dma;
> +			__u32 page_shift;
> +			__u32 page_list_len;
> +			__u32 length;
> +			__u32 access_flags;
> +			__u32 rkey;
> +		} fast_reg;
> +		struct {
> +			__u32 remote_qpn;
> +			__u32 remote_qkey;
> +			struct pvrdma_av av;
> +		} ud;
> +	} wr;
> +};

No, I have half-baked patch series which refactors this structure in kernel.
There is no need to put this structure in UAPI.

> +/* Use pvrdma_sge (ib_sge) for send queue s/g array elements. */
> +
> +/* Completion queue element. */
> +struct pvrdma_cqe {
> +	__u64 wr_id;
> +	__u64 qp;
> +	__u32 opcode;
> +	__u32 status;
> +	__u32 byte_len;
> +	__u32 imm_data;
> +	__u32 src_qp;
> +	__u32 wc_flags;
> +	__u32 vendor_err;
> +	__u16 pkey_index;
> +	__u16 slid;
> +	__u8 sl;
> +	__u8 dlid_path_bits;
> +	__u8 port_num;
> +	__u8 smac[6];
> +	__u8 reserved2[7]; /* Pad to next power of 2 (64). */
> +};
> +
> +struct pvrdma_ring {
> +	atomic_t prod_tail;	/* Producer tail. */
> +	atomic_t cons_head;	/* Consumer head. */
> +};
> +
> +struct pvrdma_ring_state {
> +	struct pvrdma_ring tx;	/* Tx ring. */
> +	struct pvrdma_ring rx;	/* Rx ring. */
> +};
> +
> +static inline int pvrdma_idx_valid(__u32 idx, __u32 max_elems)
> +{
> +	/* Generates fewer instructions than a less-than. */
> +	return (idx & ~((max_elems << 1) - 1)) == 0;
> +}
> +
> +static inline __s32 pvrdma_idx(atomic_t *var, __u32 max_elems)
> +{
> +	const unsigned int idx = atomic_read(var);
> +
> +	if (pvrdma_idx_valid(idx, max_elems))
> +		return idx & (max_elems - 1);
> +	return PVRDMA_INVALID_IDX;
> +}
> +
> +static inline void pvrdma_idx_ring_inc(atomic_t *var, __u32 max_elems)
> +{
> +	__u32 idx = atomic_read(var) + 1;	/* Increment. */

It is definitely different atomic_read than you expect. From my grep
searches on my machine, linux kernel doesn't export in standard headers
the atomic_* functions and C has their implementation of that functions.

> +
> +	idx &= (max_elems << 1) - 1;		/* Modulo size, flip gen. */
> +	atomic_set(var, idx);
> +}
> +
> +static inline __s32 pvrdma_idx_ring_has_space(const struct pvrdma_ring *r,
> +					      __u32 max_elems, __u32 *out_tail)
> +{
> +	const __u32 tail = atomic_read(&r->prod_tail);
> +	const __u32 head = atomic_read(&r->cons_head);
> +
> +	if (pvrdma_idx_valid(tail, max_elems) &&
> +	    pvrdma_idx_valid(head, max_elems)) {
> +		*out_tail = tail & (max_elems - 1);
> +		return tail != (head ^ max_elems);
> +	}
> +	return PVRDMA_INVALID_IDX;
> +}
> +
> +static inline __s32 pvrdma_idx_ring_has_data(const struct pvrdma_ring *r,
> +					     __u32 max_elems, __u32 *out_head)
> +{
> +	const __u32 tail = atomic_read(&r->prod_tail);
> +	const __u32 head = atomic_read(&r->cons_head);
> +
> +	if (pvrdma_idx_valid(tail, max_elems) &&
> +	    pvrdma_idx_valid(head, max_elems)) {
> +		*out_head = head & (max_elems - 1);
> +		return tail != head;
> +	}
> +	return PVRDMA_INVALID_IDX;
> +}
> +
> +static inline bool pvrdma_idx_ring_is_valid_idx(const struct pvrdma_ring *r,
> +						__u32 max_elems, __u32 *idx)
> +{
> +	const __u32 tail = atomic_read(&r->prod_tail);
> +	const __u32 head = atomic_read(&r->cons_head);
> +
> +	if (pvrdma_idx_valid(tail, max_elems) &&
> +	    pvrdma_idx_valid(head, max_elems) &&
> +	    pvrdma_idx_valid(*idx, max_elems)) {
> +		if (tail > head && (*idx < tail && *idx >= head))
> +			return true;
> +		else if (head > tail && (*idx >= head || *idx < tail))
> +			return true;
> +	}
> +	return false;
> +}
> +
> +#endif /* __PVRDMA_UAPI_H__ */

I suggest completely remove this file from UAPI headers folder.

Thanks.

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> 2.7.4
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