Re: [PATCH v2 11/15] IB/pvrdma: Add user-level shared functions

[Adit Ranadive <aditr-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>]

On Mon, 18 Jul 2016 16:59:07 +0300
Yuval Shaia <yuval.shaia-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> wrote:

> On Tue, Jul 12, 2016 at 12:36:41PM -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: Jorgen Hansen <jhansen-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
> > Reviewed-by: George Zhang <georgezhang-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
> > Reviewed-by: Aditya Sarwade <asarwade-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
> > Reviewed-by: Bryan Tan <bryantan-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
> > Signed-off-by: Adit Ranadive <aditr-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
> > ---
> >  drivers/infiniband/hw/pvrdma/pvrdma_uapi.h | 247
> > +++++++++++++++++++++++++++++ drivers/infiniband/hw/pvrdma/pvrdma_user.h |
> > 99 ++++++++++++ 2 files changed, 346 insertions(+)
> >  create mode 100644 drivers/infiniband/hw/pvrdma/pvrdma_uapi.h
> >  create mode 100644 drivers/infiniband/hw/pvrdma/pvrdma_user.h
> > 
> > diff --git a/drivers/infiniband/hw/pvrdma/pvrdma_uapi.h
> > b/drivers/infiniband/hw/pvrdma/pvrdma_uapi.h new file mode 100644
> > index 0000000..274328c
> > --- /dev/null
> > +++ b/drivers/infiniband/hw/pvrdma/pvrdma_uapi.h
> > @@ -0,0 +1,247 @@
> > +/*
> > + * 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
> > + *
> > https://urldefense.proofpoint.com/v2/url?u=http-3A__www.gnu.org_licenses_old-2Dlicenses_gpl-2D2.0.en.html&d=CwIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=uGpVYdpWLb65FRYUmM4EfQ&m=zWCNDfhYzlW7r0Soati7Ec2q9Vao5VNR2emCPrPrXLY&s=Tma3LbotbhNrOqLsPbVKn2noOZmFLnwQu2pOYlZqpfE&e= .
> > + *
> > + * 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
> > +
> > +#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. */ +
> > +/* PVRDMA atomic compare and swap */
> > +struct pvrdma_exp_cmp_swap {
> > +	__u64 swap_val;
> > +	__u64 compare_val;
> > +	__u64 swap_mask;
> > +	__u64 compare_mask;
> > +};
> > +
> > +/* PVRDMA atomic fetch and add */
> > +struct pvrdma_exp_fetch_add {
> > +	__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 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 receieve 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;
> > +};
> > +/* 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 -1;
> > +}
> > +
> > +static inline void pvrdma_idx_ring_inc(atomic_t *var, __u32 max_elems)
> > +{
> > +	__u32 idx = atomic_read(var) + 1;	/* Increment. */
> > +
> > +	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 -1;
> > +}
> > +
> > +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 -1;  
> 
> What is the meaning of -1?

It just means its an invalid index. I'll make that more clear in v3.

Thanks,
Adit
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html