linux/drivers/infiniband/hw/hfi1/user_exp_rcv.h
Gustavo A. R. Silva 5b361328ca RDMA: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Link: https://lore.kernel.org/r/20200213010425.GA13068@embeddedor.com
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> # added a few more
2020-02-20 13:33:51 -04:00

99 lines
3.4 KiB
C

#ifndef _HFI1_USER_EXP_RCV_H
#define _HFI1_USER_EXP_RCV_H
/*
* Copyright(c) 2015 - 2017 Intel Corporation.
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* 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 for more details.
*
* BSD 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.
* - Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 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
* OWNER 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 "hfi.h"
#include "exp_rcv.h"
struct tid_pageset {
u16 idx;
u16 count;
};
struct tid_user_buf {
unsigned long vaddr;
unsigned long length;
unsigned int npages;
struct page **pages;
struct tid_pageset *psets;
unsigned int n_psets;
};
struct tid_rb_node {
struct mmu_interval_notifier notifier;
struct hfi1_filedata *fdata;
unsigned long phys;
struct tid_group *grp;
u32 rcventry;
dma_addr_t dma_addr;
bool freed;
unsigned int npages;
struct page *pages[];
};
static inline int num_user_pages(unsigned long addr,
unsigned long len)
{
const unsigned long spage = addr & PAGE_MASK;
const unsigned long epage = (addr + len - 1) & PAGE_MASK;
return 1 + ((epage - spage) >> PAGE_SHIFT);
}
int hfi1_user_exp_rcv_init(struct hfi1_filedata *fd,
struct hfi1_ctxtdata *uctxt);
void hfi1_user_exp_rcv_free(struct hfi1_filedata *fd);
int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd,
struct hfi1_tid_info *tinfo);
int hfi1_user_exp_rcv_clear(struct hfi1_filedata *fd,
struct hfi1_tid_info *tinfo);
int hfi1_user_exp_rcv_invalid(struct hfi1_filedata *fd,
struct hfi1_tid_info *tinfo);
#endif /* _HFI1_USER_EXP_RCV_H */