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5b361328ca
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
93 lines
3.4 KiB
C
93 lines
3.4 KiB
C
/*
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* Copyright (c) 2004 Topspin Corporation. All rights reserved.
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* Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
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*
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* This software is available to you under a choice of one of two
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* licenses. You may choose to be licensed under the terms of the GNU
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* General Public License (GPL) Version 2, available from the file
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* COPYING in the main directory of this source tree, or the
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* OpenIB.org BSD license below:
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* - Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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*
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* - Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#if !defined(IB_FMR_POOL_H)
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#define IB_FMR_POOL_H
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#include <rdma/ib_verbs.h>
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struct ib_fmr_pool;
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/**
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* struct ib_fmr_pool_param - Parameters for creating FMR pool
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* @max_pages_per_fmr:Maximum number of pages per map request.
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* @page_shift: Log2 of sizeof "pages" mapped by this fmr
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* @access:Access flags for FMRs in pool.
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* @pool_size:Number of FMRs to allocate for pool.
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* @dirty_watermark:Flush is triggered when @dirty_watermark dirty
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* FMRs are present.
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* @flush_function:Callback called when unmapped FMRs are flushed and
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* more FMRs are possibly available for mapping
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* @flush_arg:Context passed to user's flush function.
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* @cache:If set, FMRs may be reused after unmapping for identical map
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* requests.
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*/
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struct ib_fmr_pool_param {
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int max_pages_per_fmr;
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int page_shift;
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enum ib_access_flags access;
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int pool_size;
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int dirty_watermark;
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void (*flush_function)(struct ib_fmr_pool *pool,
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void *arg);
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void *flush_arg;
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unsigned cache:1;
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};
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struct ib_pool_fmr {
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struct ib_fmr *fmr;
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struct ib_fmr_pool *pool;
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struct list_head list;
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struct hlist_node cache_node;
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int ref_count;
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int remap_count;
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u64 io_virtual_address;
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int page_list_len;
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u64 page_list[];
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};
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struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd *pd,
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struct ib_fmr_pool_param *params);
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void ib_destroy_fmr_pool(struct ib_fmr_pool *pool);
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int ib_flush_fmr_pool(struct ib_fmr_pool *pool);
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struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
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u64 *page_list,
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int list_len,
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u64 io_virtual_address);
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void ib_fmr_pool_unmap(struct ib_pool_fmr *fmr);
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#endif /* IB_FMR_POOL_H */
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