[PATCH 36/41] IB/hfi1: add low level page locking

Mike Marciniszyn
2015-06-11T23:11:42Z

drivers/infiniband/hw/hfi1/user_pages.c | 156 +++++++++++++++++++++++++++++++
1 file changed, 156 insertions(+)
create mode 100644 drivers/infiniband/hw/hfi1/user_pages.c

diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c
new file mode 100644
index 0000000..9071afb
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/user_pages.c
@@ -0,0 +1,156 @@
+/*
+ *
+ * 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
+ *
+ * Copyright(c) 2015 Intel Corporation.
+ *
+ * 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
+ *
+ * Copyright(c) 2015 Intel Corporation.
+ *
+ * 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 <linux/mm.h>
+#include <linux/device.h>
+
+#include "hfi.h"
+
+static void __hfi1_release_user_pages(struct page **p, size_t num_pages,
+ int dirty)
+{
+ size_t i;
+
+ for (i = 0; i < num_pages; i++) {
+ if (dirty)
+ set_page_dirty_lock(p[i]);
+ put_page(p[i]);
+ }
+}
+
+/*
+ * Call with current->mm->mmap_sem held.
+ */
+static int __hfi1_get_user_pages(unsigned long start_page, size_t num_pages,
+ struct page **p)
+{
+ unsigned long lock_limit;
+ size_t got;
+ int ret;
+
+ lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+
+ if (num_pages > lock_limit && !capable(CAP_IPC_LOCK)) {
+ ret = -ENOMEM;
+ goto bail;
+ }
+
+ for (got = 0; got < num_pages; got += ret) {
+ ret = get_user_pages(current, current->mm,
+ start_page + got * PAGE_SIZE,
+ num_pages - got, 1, 1,
+ p + got, NULL);
+ if (ret < 0)
+ goto bail_release;
+ }
+
+ current->mm->pinned_vm += num_pages;
+
+ ret = 0;
+ goto bail;
+
+bail_release:
+ __hfi1_release_user_pages(p, got, 0);
+bail:
+ return ret;
+}
+
+/**
+ * hfi1_map_page - a safety wrapper around pci_map_page()
+ *
+ */
+dma_addr_t hfi1_map_page(struct pci_dev *hwdev, struct page *page,
+ unsigned long offset, size_t size, int direction)
+{
+ dma_addr_t phys;
+
+ phys = pci_map_page(hwdev, page, offset, size, direction);
+
+ return phys;
+}
+
+/**
+ * hfi1_get_user_pages - lock user pages into memory
+ * @start_page: the start page
+ * @num_pages: the number of pages
+ * @p: the output page structures
+ *
+ * This function takes a given start page (page aligned user virtual
+ * address) and pins it and the following specified number of pages. For
+ * now, num_pages is always 1, but that will probably change at some point
+ * (because caller is doing expected sends on a single virtually contiguous
+ * buffer, so we can do all pages at once).
+ */
+int hfi1_get_user_pages(unsigned long start_page, size_t num_pages,
+ struct page **p)
+{
+ int ret;
+
+ down_write(&current->mm->mmap_sem);
+
+ ret = __hfi1_get_user_pages(start_page, num_pages, p);
+
+ up_write(&current->mm->mmap_sem);
+
+ return ret;
+}
+
+void hfi1_release_user_pages(struct page **p, size_t num_pages)
+{
+ if (current->mm) /* during close after signal, mm can be NULL */
+ down_write(&current->mm->mmap_sem);
+
+ __hfi1_release_user_pages(p, num_pages, 1);
+
+ if (current->mm) {
+ current->mm->pinned_vm -= num_pages;
+ up_write(&current->mm->mmap_sem);