umem.c

  1/*
  2 * Copyright (c) 2005 Topspin Communications.  All rights reserved.
  3 * Copyright (c) 2005 Cisco Systems.  All rights reserved.
  4 * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
  5 * Copyright (c) 2020 Intel Corporation. All rights reserved.
  6 *
  7 * This software is available to you under a choice of one of two
  8 * licenses.  You may choose to be licensed under the terms of the GNU
  9 * General Public License (GPL) Version 2, available from the file
 10 * COPYING in the main directory of this source tree, or the
 11 * OpenIB.org BSD license below:
 12 *
 13 *     Redistribution and use in source and binary forms, with or
 14 *     without modification, are permitted provided that the following
 15 *     conditions are met:
 16 *
 17 *      - Redistributions of source code must retain the above
 18 *        copyright notice, this list of conditions and the following
 19 *        disclaimer.
 20 *
 21 *      - Redistributions in binary form must reproduce the above
 22 *        copyright notice, this list of conditions and the following
 23 *        disclaimer in the documentation and/or other materials
 24 *        provided with the distribution.
 25 *
 26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 27 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 28 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 29 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 30 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 31 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 32 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 33 * SOFTWARE.
 34 */
 35
 36#include <linux/mm.h>
 37#include <linux/dma-mapping.h>
 38#include <linux/sched/signal.h>
 39#include <linux/sched/mm.h>
 40#include <linux/export.h>
 41#include <linux/slab.h>
 42#include <linux/pagemap.h>
 43#include <linux/count_zeros.h>
 44#include <rdma/ib_umem_odp.h>
 45
 46#include "uverbs.h"
 47
 48#define RESCHED_LOOP_CNT_THRESHOLD 0x1000
 49
 50static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
 51{
 52	bool make_dirty = umem->writable && dirty;
 53	struct scatterlist *sg;
 54	unsigned int i;
 55
 56	if (dirty)
 57		ib_dma_unmap_sgtable_attrs(dev, &umem->sgt_append.sgt,
 58					   DMA_BIDIRECTIONAL, 0);
 59
 60	for_each_sgtable_sg(&umem->sgt_append.sgt, sg, i) {
 61		unpin_user_page_range_dirty_lock(sg_page(sg),
 62			DIV_ROUND_UP(sg->length, PAGE_SIZE), make_dirty);
 63
 64		if (i && !(i % RESCHED_LOOP_CNT_THRESHOLD))
 65			cond_resched();
 66	}
 67
 68	sg_free_append_table(&umem->sgt_append);
 69}
 70
 71/**
 72 * ib_umem_find_best_pgsz - Find best HW page size to use for this MR
 73 *
 74 * @umem: umem struct
 75 * @pgsz_bitmap: bitmap of HW supported page sizes
 76 * @virt: IOVA
 77 *
 78 * This helper is intended for HW that support multiple page
 79 * sizes but can do only a single page size in an MR.
 80 *
 81 * Returns 0 if the umem requires page sizes not supported by
 82 * the driver to be mapped. Drivers always supporting PAGE_SIZE
 83 * or smaller will never see a 0 result.
 84 */
 85unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
 86				     unsigned long pgsz_bitmap,
 87				     unsigned long virt)
 88{
 89	unsigned long curr_len = 0;
 90	dma_addr_t curr_base = ~0;
 91	unsigned long va, pgoff;
 92	struct scatterlist *sg;
 93	dma_addr_t mask;
 94	dma_addr_t end;
 95	int i;
 96
 97	umem->iova = va = virt;
 98
 99	if (umem->is_odp) {
100		unsigned int page_size = BIT(to_ib_umem_odp(umem)->page_shift);
101
102		/* ODP must always be self consistent. */
103		if (!(pgsz_bitmap & page_size))
104			return 0;
105		return page_size;
106	}
107
108	/* The best result is the smallest page size that results in the minimum
109	 * number of required pages. Compute the largest page size that could
110	 * work based on VA address bits that don't change.
111	 */
112	mask = pgsz_bitmap &
113	       GENMASK(BITS_PER_LONG - 1,
114		       bits_per((umem->length - 1 + virt) ^ virt));
115	/* offset into first SGL */
116	pgoff = umem->address & ~PAGE_MASK;
117
118	for_each_sgtable_dma_sg(&umem->sgt_append.sgt, sg, i) {
119		/* If the current entry is physically contiguous with the previous
120		 * one, no need to take its start addresses into consideration.
121		 */
122		if (check_add_overflow(curr_base, curr_len, &end) ||
123		    end != sg_dma_address(sg)) {
124
125			curr_base = sg_dma_address(sg);
126			curr_len = 0;
127
128			/* Reduce max page size if VA/PA bits differ */
129			mask |= (curr_base + pgoff) ^ va;
130
131			/* The alignment of any VA matching a discontinuity point
132			* in the physical memory sets the maximum possible page
133			* size as this must be a starting point of a new page that
134			* needs to be aligned.
135			*/
136			if (i != 0)
137				mask |= va;
138		}
139
140		curr_len += sg_dma_len(sg);
141		va += sg_dma_len(sg) - pgoff;
142
143		pgoff = 0;
144	}
145
146	/* The mask accumulates 1's in each position where the VA and physical
147	 * address differ, thus the length of trailing 0 is the largest page
148	 * size that can pass the VA through to the physical.
149	 */
150	if (mask)
151		pgsz_bitmap &= GENMASK(count_trailing_zeros(mask), 0);
152	return pgsz_bitmap ? rounddown_pow_of_two(pgsz_bitmap) : 0;
153}
154EXPORT_SYMBOL(ib_umem_find_best_pgsz);
155
156/**
157 * ib_umem_get - Pin and DMA map userspace memory.
158 *
159 * @device: IB device to connect UMEM
160 * @addr: userspace virtual address to start at
161 * @size: length of region to pin
162 * @access: IB_ACCESS_xxx flags for memory being pinned
163 */
164struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
165			    size_t size, int access)
166{
167	struct ib_umem *umem;
168	struct page **page_list;
169	unsigned long lock_limit;
170	unsigned long new_pinned;
171	unsigned long cur_base;
172	unsigned long dma_attr = 0;
173	struct mm_struct *mm;
174	unsigned long npages;
175	int pinned, ret;
176	unsigned int gup_flags = FOLL_LONGTERM;
177
178	/*
179	 * If the combination of the addr and size requested for this memory
180	 * region causes an integer overflow, return error.
181	 */
182	if (((addr + size) < addr) ||
183	    PAGE_ALIGN(addr + size) < (addr + size))
184		return ERR_PTR(-EINVAL);
185
186	if (!can_do_mlock())
187		return ERR_PTR(-EPERM);
188
189	if (access & IB_ACCESS_ON_DEMAND)
190		return ERR_PTR(-EOPNOTSUPP);
191
192	umem = kzalloc(sizeof(*umem), GFP_KERNEL);
193	if (!umem)
194		return ERR_PTR(-ENOMEM);
195	umem->ibdev      = device;
196	umem->length     = size;
197	umem->address    = addr;
198	/*
199	 * Drivers should call ib_umem_find_best_pgsz() to set the iova
200	 * correctly.
201	 */
202	umem->iova = addr;
203	umem->writable   = ib_access_writable(access);
204	umem->owning_mm = mm = current->mm;
205	mmgrab(mm);
206
207	page_list = (struct page **) __get_free_page(GFP_KERNEL);
208	if (!page_list) {
209		ret = -ENOMEM;
210		goto umem_kfree;
211	}
212
213	npages = ib_umem_num_pages(umem);
214	if (npages == 0 || npages > UINT_MAX) {
215		ret = -EINVAL;
216		goto out;
217	}
218
219	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
220
221	new_pinned = atomic64_add_return(npages, &mm->pinned_vm);
222	if (new_pinned > lock_limit && !capable(CAP_IPC_LOCK)) {
223		atomic64_sub(npages, &mm->pinned_vm);
224		ret = -ENOMEM;
225		goto out;
226	}
227
228	cur_base = addr & PAGE_MASK;
229
230	if (umem->writable)
231		gup_flags |= FOLL_WRITE;
232
233	while (npages) {
234		cond_resched();
235		pinned = pin_user_pages_fast(cur_base,
236					  min_t(unsigned long, npages,
237						PAGE_SIZE /
238						sizeof(struct page *)),
239					  gup_flags, page_list);
240		if (pinned < 0) {
241			ret = pinned;
242			goto umem_release;
243		}
244
245		cur_base += pinned * PAGE_SIZE;
246		npages -= pinned;
247		ret = sg_alloc_append_table_from_pages(
248			&umem->sgt_append, page_list, pinned, 0,
249			pinned << PAGE_SHIFT, ib_dma_max_seg_size(device),
250			npages, GFP_KERNEL);
251		if (ret) {
252			unpin_user_pages_dirty_lock(page_list, pinned, 0);
253			goto umem_release;
254		}
255	}
256
257	if (access & IB_ACCESS_RELAXED_ORDERING)
258		dma_attr |= DMA_ATTR_WEAK_ORDERING;
259
260	ret = ib_dma_map_sgtable_attrs(device, &umem->sgt_append.sgt,
261				       DMA_BIDIRECTIONAL, dma_attr);
262	if (ret)
263		goto umem_release;
264	goto out;
265
266umem_release:
267	__ib_umem_release(device, umem, 0);
268	atomic64_sub(ib_umem_num_pages(umem), &mm->pinned_vm);
269out:
270	free_page((unsigned long) page_list);
271umem_kfree:
272	if (ret) {
273		mmdrop(umem->owning_mm);
274		kfree(umem);
275	}
276	return ret ? ERR_PTR(ret) : umem;
277}
278EXPORT_SYMBOL(ib_umem_get);
279
280/**
281 * ib_umem_release - release memory pinned with ib_umem_get
282 * @umem: umem struct to release
283 */
284void ib_umem_release(struct ib_umem *umem)
285{
286	if (!umem)
287		return;
288	if (umem->is_dmabuf)
289		return ib_umem_dmabuf_release(to_ib_umem_dmabuf(umem));
290	if (umem->is_odp)
291		return ib_umem_odp_release(to_ib_umem_odp(umem));
292
293	__ib_umem_release(umem->ibdev, umem, 1);
294
295	atomic64_sub(ib_umem_num_pages(umem), &umem->owning_mm->pinned_vm);
296	mmdrop(umem->owning_mm);
297	kfree(umem);
298}
299EXPORT_SYMBOL(ib_umem_release);
300
301/*
302 * Copy from the given ib_umem's pages to the given buffer.
303 *
304 * umem - the umem to copy from
305 * offset - offset to start copying from
306 * dst - destination buffer
307 * length - buffer length
308 *
309 * Returns 0 on success, or an error code.
310 */
311int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
312		      size_t length)
313{
314	size_t end = offset + length;
315	int ret;
316
317	if (offset > umem->length || length > umem->length - offset) {
318		pr_err("%s not in range. offset: %zd umem length: %zd end: %zd\n",
319		       __func__, offset, umem->length, end);
320		return -EINVAL;
321	}
322
323	ret = sg_pcopy_to_buffer(umem->sgt_append.sgt.sgl,
324				 umem->sgt_append.sgt.orig_nents, dst, length,
325				 offset + ib_umem_offset(umem));
326
327	if (ret < 0)
328		return ret;
329	else if (ret != length)
330		return -EINVAL;
331	else
332		return 0;
333}
334EXPORT_SYMBOL(ib_umem_copy_from);