cregit-Linux how code gets into the kernel

Release 4.7 drivers/infiniband/hw/hfi1/user_pages.c

/*
 * Copyright(c) 2015, 2016 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/module.h>

#include "hfi.h"


static unsigned long cache_size = 256;
module_param(cache_size, ulong, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(cache_size, "Send and receive side cache size limit (in MB)");

/*
 * Determine whether the caller can pin pages.
 *
 * This function should be used in the implementation of buffer caches.
 * The cache implementation should call this function prior to attempting
 * to pin buffer pages in order to determine whether they should do so.
 * The function computes cache limits based on the configured ulimit and
 * cache size. Use of this function is especially important for caches
 * which are not limited in any other way (e.g. by HW resources) and, thus,
 * could keeping caching buffers.
 *
 */

bool hfi1_can_pin_pages(struct hfi1_devdata *dd, u32 nlocked, u32 npages) { unsigned long ulimit = rlimit(RLIMIT_MEMLOCK), pinned, cache_limit, size = (cache_size * (1UL << 20)); /* convert to bytes */ unsigned usr_ctxts = dd->num_rcv_contexts - dd->first_user_ctxt; bool can_lock = capable(CAP_IPC_LOCK); /* * Calculate per-cache size. The calculation below uses only a quarter * of the available per-context limit. This leaves space for other * pinning. Should we worry about shared ctxts? */ cache_limit = (ulimit / usr_ctxts) / 4; /* If ulimit isn't set to "unlimited" and is smaller than cache_size. */ if (ulimit != (-1UL) && size > cache_limit) size = cache_limit; /* Convert to number of pages */ size = DIV_ROUND_UP(size, PAGE_SIZE); down_read(&current->mm->mmap_sem); pinned = current->mm->pinned_vm; up_read(&current->mm->mmap_sem); /* First, check the absolute limit against all pinned pages. */ if (pinned + npages >= ulimit && !can_lock) return false; return ((nlocked + npages) <= size) || can_lock; }

Contributors

PersonTokensPropCommitsCommitProp
mitko haralanovmitko haralanov14391.67%266.67%
mike marciniszynmike marciniszyn138.33%133.33%
Total156100.00%3100.00%


int hfi1_acquire_user_pages(unsigned long vaddr, size_t npages, bool writable, struct page **pages) { int ret; ret = get_user_pages_fast(vaddr, npages, writable, pages); if (ret < 0) return ret; down_write(&current->mm->mmap_sem); current->mm->pinned_vm += ret; up_write(&current->mm->mmap_sem); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
mitko haralanovmitko haralanov5672.73%266.67%
mike marciniszynmike marciniszyn2127.27%133.33%
Total77100.00%3100.00%


void hfi1_release_user_pages(struct mm_struct *mm, struct page **p, size_t npages, bool dirty) { size_t i; for (i = 0; i < npages; i++) { if (dirty) set_page_dirty_lock(p[i]); put_page(p[i]); } if (mm) { /* during close after signal, mm can be NULL */ down_write(&mm->mmap_sem); mm->pinned_vm -= npages; up_write(&mm->mmap_sem); } }

Contributors

PersonTokensPropCommitsCommitProp
mitko haralanovmitko haralanov4752.81%266.67%
mike marciniszynmike marciniszyn4247.19%133.33%
Total89100.00%3100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
mitko haralanovmitko haralanov27675.82%360.00%
mike marciniszynmike marciniszyn8723.90%120.00%
jubin johnjubin john10.27%120.00%
Total364100.00%5100.00%
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