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453b329b JA |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/kernel.h> | |
3 | #include <linux/errno.h> | |
4 | #include <linux/file.h> | |
5 | #include <linux/mm.h> | |
6 | #include <linux/slab.h> | |
c98817e6 | 7 | #include <linux/nospec.h> |
453b329b JA |
8 | #include <linux/io_uring.h> |
9 | ||
10 | #include <uapi/linux/io_uring.h> | |
11 | ||
453b329b | 12 | #include "io_uring.h" |
c98817e6 JA |
13 | #include "rsrc.h" |
14 | #include "filetable.h" | |
453b329b | 15 | |
c98817e6 | 16 | static int io_file_bitmap_get(struct io_ring_ctx *ctx) |
453b329b JA |
17 | { |
18 | struct io_file_table *table = &ctx->file_table; | |
6e73dffb | 19 | unsigned long nr = ctx->file_alloc_end; |
453b329b JA |
20 | int ret; |
21 | ||
22 | do { | |
23 | ret = find_next_zero_bit(table->bitmap, nr, table->alloc_hint); | |
24 | if (ret != nr) | |
25 | return ret; | |
26 | ||
6e73dffb | 27 | if (table->alloc_hint == ctx->file_alloc_start) |
453b329b | 28 | break; |
453b329b | 29 | nr = table->alloc_hint; |
6e73dffb | 30 | table->alloc_hint = ctx->file_alloc_start; |
453b329b JA |
31 | } while (1); |
32 | ||
33 | return -ENFILE; | |
34 | } | |
35 | ||
36 | bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files) | |
37 | { | |
38 | table->files = kvcalloc(nr_files, sizeof(table->files[0]), | |
39 | GFP_KERNEL_ACCOUNT); | |
40 | if (unlikely(!table->files)) | |
41 | return false; | |
42 | ||
43 | table->bitmap = bitmap_zalloc(nr_files, GFP_KERNEL_ACCOUNT); | |
44 | if (unlikely(!table->bitmap)) { | |
45 | kvfree(table->files); | |
46 | return false; | |
47 | } | |
48 | ||
49 | return true; | |
50 | } | |
51 | ||
52 | void io_free_file_tables(struct io_file_table *table) | |
53 | { | |
54 | kvfree(table->files); | |
55 | bitmap_free(table->bitmap); | |
56 | table->files = NULL; | |
57 | table->bitmap = NULL; | |
58 | } | |
c98817e6 | 59 | |
f110ed84 JA |
60 | static int io_install_fixed_file(struct io_ring_ctx *ctx, struct file *file, |
61 | u32 slot_index) | |
c98817e6 JA |
62 | __must_hold(&req->ctx->uring_lock) |
63 | { | |
c98817e6 JA |
64 | bool needs_switch = false; |
65 | struct io_fixed_file *file_slot; | |
66 | int ret; | |
67 | ||
68 | if (io_is_uring_fops(file)) | |
69 | return -EBADF; | |
70 | if (!ctx->file_data) | |
71 | return -ENXIO; | |
72 | if (slot_index >= ctx->nr_user_files) | |
73 | return -EINVAL; | |
74 | ||
75 | slot_index = array_index_nospec(slot_index, ctx->nr_user_files); | |
76 | file_slot = io_fixed_file_slot(&ctx->file_table, slot_index); | |
77 | ||
78 | if (file_slot->file_ptr) { | |
79 | struct file *old_file; | |
80 | ||
81 | ret = io_rsrc_node_switch_start(ctx); | |
82 | if (ret) | |
83 | goto err; | |
84 | ||
85 | old_file = (struct file *)(file_slot->file_ptr & FFS_MASK); | |
86 | ret = io_queue_rsrc_removal(ctx->file_data, slot_index, | |
87 | ctx->rsrc_node, old_file); | |
88 | if (ret) | |
89 | goto err; | |
90 | file_slot->file_ptr = 0; | |
91 | io_file_bitmap_clear(&ctx->file_table, slot_index); | |
92 | needs_switch = true; | |
93 | } | |
94 | ||
95 | ret = io_scm_file_account(ctx, file); | |
96 | if (!ret) { | |
97 | *io_get_tag_slot(ctx->file_data, slot_index) = 0; | |
98 | io_fixed_file_set(file_slot, file); | |
99 | io_file_bitmap_set(&ctx->file_table, slot_index); | |
100 | } | |
101 | err: | |
102 | if (needs_switch) | |
103 | io_rsrc_node_switch(ctx, ctx->file_data); | |
104 | if (ret) | |
105 | fput(file); | |
106 | return ret; | |
107 | } | |
108 | ||
f110ed84 JA |
109 | int __io_fixed_fd_install(struct io_ring_ctx *ctx, struct file *file, |
110 | unsigned int file_slot) | |
c98817e6 JA |
111 | { |
112 | bool alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC; | |
c98817e6 JA |
113 | int ret; |
114 | ||
c98817e6 JA |
115 | if (alloc_slot) { |
116 | ret = io_file_bitmap_get(ctx); | |
117 | if (unlikely(ret < 0)) | |
f110ed84 | 118 | return ret; |
c98817e6 JA |
119 | file_slot = ret; |
120 | } else { | |
121 | file_slot--; | |
122 | } | |
123 | ||
f110ed84 | 124 | ret = io_install_fixed_file(ctx, file, file_slot); |
c98817e6 JA |
125 | if (!ret && alloc_slot) |
126 | ret = file_slot; | |
f110ed84 JA |
127 | return ret; |
128 | } | |
129 | /* | |
130 | * Note when io_fixed_fd_install() returns error value, it will ensure | |
131 | * fput() is called correspondingly. | |
132 | */ | |
133 | int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags, | |
134 | struct file *file, unsigned int file_slot) | |
135 | { | |
136 | struct io_ring_ctx *ctx = req->ctx; | |
137 | int ret; | |
138 | ||
139 | io_ring_submit_lock(ctx, issue_flags); | |
140 | ret = __io_fixed_fd_install(ctx, file, file_slot); | |
c98817e6 | 141 | io_ring_submit_unlock(ctx, issue_flags); |
f110ed84 | 142 | |
c98817e6 JA |
143 | if (unlikely(ret < 0)) |
144 | fput(file); | |
145 | return ret; | |
146 | } | |
f110ed84 JA |
147 | |
148 | int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset) | |
149 | { | |
150 | struct io_fixed_file *file_slot; | |
151 | struct file *file; | |
152 | int ret; | |
153 | ||
154 | if (unlikely(!ctx->file_data)) | |
155 | return -ENXIO; | |
156 | if (offset >= ctx->nr_user_files) | |
157 | return -EINVAL; | |
158 | ret = io_rsrc_node_switch_start(ctx); | |
159 | if (ret) | |
160 | return ret; | |
161 | ||
162 | offset = array_index_nospec(offset, ctx->nr_user_files); | |
163 | file_slot = io_fixed_file_slot(&ctx->file_table, offset); | |
164 | if (!file_slot->file_ptr) | |
165 | return -EBADF; | |
166 | ||
167 | file = (struct file *)(file_slot->file_ptr & FFS_MASK); | |
168 | ret = io_queue_rsrc_removal(ctx->file_data, offset, ctx->rsrc_node, file); | |
169 | if (ret) | |
170 | return ret; | |
171 | ||
172 | file_slot->file_ptr = 0; | |
173 | io_file_bitmap_clear(&ctx->file_table, offset); | |
174 | io_rsrc_node_switch(ctx, ctx->file_data); | |
175 | return 0; | |
176 | } | |
6e73dffb PB |
177 | |
178 | int io_register_file_alloc_range(struct io_ring_ctx *ctx, | |
179 | struct io_uring_file_index_range __user *arg) | |
180 | { | |
181 | struct io_uring_file_index_range range; | |
182 | u32 end; | |
183 | ||
184 | if (copy_from_user(&range, arg, sizeof(range))) | |
185 | return -EFAULT; | |
186 | if (check_add_overflow(range.off, range.len, &end)) | |
187 | return -EOVERFLOW; | |
188 | if (range.resv || end > ctx->nr_user_files) | |
189 | return -EINVAL; | |
190 | ||
191 | io_file_table_set_alloc_range(ctx, range.off, range.len); | |
192 | return 0; | |
193 | } |