Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-2.6-microblaze.git] / net / xdp / xdp_umem.c
1 // SPDX-License-Identifier: GPL-2.0
2 /* XDP user-space packet buffer
3  * Copyright(c) 2018 Intel Corporation.
4  */
5
6 #include <linux/init.h>
7 #include <linux/sched/mm.h>
8 #include <linux/sched/signal.h>
9 #include <linux/sched/task.h>
10 #include <linux/uaccess.h>
11 #include <linux/slab.h>
12 #include <linux/bpf.h>
13 #include <linux/mm.h>
14 #include <linux/netdevice.h>
15 #include <linux/rtnetlink.h>
16 #include <linux/idr.h>
17 #include <linux/vmalloc.h>
18
19 #include "xdp_umem.h"
20 #include "xsk_queue.h"
21
22 #define XDP_UMEM_MIN_CHUNK_SIZE 2048
23
24 static DEFINE_IDA(umem_ida);
25
26 static void xdp_umem_unpin_pages(struct xdp_umem *umem)
27 {
28         unpin_user_pages_dirty_lock(umem->pgs, umem->npgs, true);
29
30         kvfree(umem->pgs);
31         umem->pgs = NULL;
32 }
33
34 static void xdp_umem_unaccount_pages(struct xdp_umem *umem)
35 {
36         if (umem->user) {
37                 atomic_long_sub(umem->npgs, &umem->user->locked_vm);
38                 free_uid(umem->user);
39         }
40 }
41
42 static void xdp_umem_addr_unmap(struct xdp_umem *umem)
43 {
44         vunmap(umem->addrs);
45         umem->addrs = NULL;
46 }
47
48 static int xdp_umem_addr_map(struct xdp_umem *umem, struct page **pages,
49                              u32 nr_pages)
50 {
51         umem->addrs = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
52         if (!umem->addrs)
53                 return -ENOMEM;
54         return 0;
55 }
56
57 static void xdp_umem_release(struct xdp_umem *umem)
58 {
59         umem->zc = false;
60         ida_simple_remove(&umem_ida, umem->id);
61
62         xdp_umem_addr_unmap(umem);
63         xdp_umem_unpin_pages(umem);
64
65         xdp_umem_unaccount_pages(umem);
66         kfree(umem);
67 }
68
69 static void xdp_umem_release_deferred(struct work_struct *work)
70 {
71         struct xdp_umem *umem = container_of(work, struct xdp_umem, work);
72
73         xdp_umem_release(umem);
74 }
75
76 void xdp_get_umem(struct xdp_umem *umem)
77 {
78         refcount_inc(&umem->users);
79 }
80
81 void xdp_put_umem(struct xdp_umem *umem, bool defer_cleanup)
82 {
83         if (!umem)
84                 return;
85
86         if (refcount_dec_and_test(&umem->users)) {
87                 if (defer_cleanup) {
88                         INIT_WORK(&umem->work, xdp_umem_release_deferred);
89                         schedule_work(&umem->work);
90                 } else {
91                         xdp_umem_release(umem);
92                 }
93         }
94 }
95
96 static int xdp_umem_pin_pages(struct xdp_umem *umem, unsigned long address)
97 {
98         unsigned int gup_flags = FOLL_WRITE;
99         long npgs;
100         int err;
101
102         umem->pgs = kvcalloc(umem->npgs, sizeof(*umem->pgs), GFP_KERNEL | __GFP_NOWARN);
103         if (!umem->pgs)
104                 return -ENOMEM;
105
106         mmap_read_lock(current->mm);
107         npgs = pin_user_pages(address, umem->npgs,
108                               gup_flags | FOLL_LONGTERM, &umem->pgs[0], NULL);
109         mmap_read_unlock(current->mm);
110
111         if (npgs != umem->npgs) {
112                 if (npgs >= 0) {
113                         umem->npgs = npgs;
114                         err = -ENOMEM;
115                         goto out_pin;
116                 }
117                 err = npgs;
118                 goto out_pgs;
119         }
120         return 0;
121
122 out_pin:
123         xdp_umem_unpin_pages(umem);
124 out_pgs:
125         kvfree(umem->pgs);
126         umem->pgs = NULL;
127         return err;
128 }
129
130 static int xdp_umem_account_pages(struct xdp_umem *umem)
131 {
132         unsigned long lock_limit, new_npgs, old_npgs;
133
134         if (capable(CAP_IPC_LOCK))
135                 return 0;
136
137         lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
138         umem->user = get_uid(current_user());
139
140         do {
141                 old_npgs = atomic_long_read(&umem->user->locked_vm);
142                 new_npgs = old_npgs + umem->npgs;
143                 if (new_npgs > lock_limit) {
144                         free_uid(umem->user);
145                         umem->user = NULL;
146                         return -ENOBUFS;
147                 }
148         } while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs,
149                                      new_npgs) != old_npgs);
150         return 0;
151 }
152
153 static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
154 {
155         u32 npgs_rem, chunk_size = mr->chunk_size, headroom = mr->headroom;
156         bool unaligned_chunks = mr->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG;
157         u64 npgs, addr = mr->addr, size = mr->len;
158         unsigned int chunks, chunks_rem;
159         int err;
160
161         if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) {
162                 /* Strictly speaking we could support this, if:
163                  * - huge pages, or*
164                  * - using an IOMMU, or
165                  * - making sure the memory area is consecutive
166                  * but for now, we simply say "computer says no".
167                  */
168                 return -EINVAL;
169         }
170
171         if (mr->flags & ~XDP_UMEM_UNALIGNED_CHUNK_FLAG)
172                 return -EINVAL;
173
174         if (!unaligned_chunks && !is_power_of_2(chunk_size))
175                 return -EINVAL;
176
177         if (!PAGE_ALIGNED(addr)) {
178                 /* Memory area has to be page size aligned. For
179                  * simplicity, this might change.
180                  */
181                 return -EINVAL;
182         }
183
184         if ((addr + size) < addr)
185                 return -EINVAL;
186
187         npgs = div_u64_rem(size, PAGE_SIZE, &npgs_rem);
188         if (npgs_rem)
189                 npgs++;
190         if (npgs > U32_MAX)
191                 return -EINVAL;
192
193         chunks = (unsigned int)div_u64_rem(size, chunk_size, &chunks_rem);
194         if (chunks == 0)
195                 return -EINVAL;
196
197         if (!unaligned_chunks && chunks_rem)
198                 return -EINVAL;
199
200         if (headroom >= chunk_size - XDP_PACKET_HEADROOM)
201                 return -EINVAL;
202
203         umem->size = size;
204         umem->headroom = headroom;
205         umem->chunk_size = chunk_size;
206         umem->chunks = chunks;
207         umem->npgs = (u32)npgs;
208         umem->pgs = NULL;
209         umem->user = NULL;
210         umem->flags = mr->flags;
211
212         INIT_LIST_HEAD(&umem->xsk_dma_list);
213         refcount_set(&umem->users, 1);
214
215         err = xdp_umem_account_pages(umem);
216         if (err)
217                 return err;
218
219         err = xdp_umem_pin_pages(umem, (unsigned long)addr);
220         if (err)
221                 goto out_account;
222
223         err = xdp_umem_addr_map(umem, umem->pgs, umem->npgs);
224         if (err)
225                 goto out_unpin;
226
227         return 0;
228
229 out_unpin:
230         xdp_umem_unpin_pages(umem);
231 out_account:
232         xdp_umem_unaccount_pages(umem);
233         return err;
234 }
235
236 struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr)
237 {
238         struct xdp_umem *umem;
239         int err;
240
241         umem = kzalloc(sizeof(*umem), GFP_KERNEL);
242         if (!umem)
243                 return ERR_PTR(-ENOMEM);
244
245         err = ida_simple_get(&umem_ida, 0, 0, GFP_KERNEL);
246         if (err < 0) {
247                 kfree(umem);
248                 return ERR_PTR(err);
249         }
250         umem->id = err;
251
252         err = xdp_umem_reg(umem, mr);
253         if (err) {
254                 ida_simple_remove(&umem_ida, umem->id);
255                 kfree(umem);
256                 return ERR_PTR(err);
257         }
258
259         return umem;
260 }