Tejun Heo | b8441ed | 2013-11-24 09:54:58 -0500 | [diff] [blame] | 1 | /* |
| 2 | * fs/kernfs/file.c - kernfs file implementation |
| 3 | * |
| 4 | * Copyright (c) 2001-3 Patrick Mochel |
| 5 | * Copyright (c) 2007 SUSE Linux Products GmbH |
| 6 | * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org> |
| 7 | * |
| 8 | * This file is released under the GPLv2. |
| 9 | */ |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 10 | |
| 11 | #include <linux/fs.h> |
| 12 | #include <linux/seq_file.h> |
| 13 | #include <linux/slab.h> |
| 14 | #include <linux/poll.h> |
| 15 | #include <linux/pagemap.h> |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 16 | #include <linux/sched.h> |
| 17 | |
| 18 | #include "kernfs-internal.h" |
| 19 | |
| 20 | /* |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 21 | * There's one kernfs_open_file for each open file and one kernfs_open_node |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 22 | * for each kernfs_node with one or more open files. |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 23 | * |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 24 | * kernfs_node->attr.open points to kernfs_open_node. attr.open is |
| 25 | * protected by kernfs_open_node_lock. |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 26 | * |
| 27 | * filp->private_data points to seq_file whose ->private points to |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 28 | * kernfs_open_file. kernfs_open_files are chained at |
| 29 | * kernfs_open_node->files, which is protected by kernfs_open_file_mutex. |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 30 | */ |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 31 | static DEFINE_SPINLOCK(kernfs_open_node_lock); |
| 32 | static DEFINE_MUTEX(kernfs_open_file_mutex); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 33 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 34 | struct kernfs_open_node { |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 35 | atomic_t refcnt; |
| 36 | atomic_t event; |
| 37 | wait_queue_head_t poll; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 38 | struct list_head files; /* goes through kernfs_open_file.list */ |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 39 | }; |
| 40 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 41 | static struct kernfs_open_file *kernfs_of(struct file *file) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 42 | { |
| 43 | return ((struct seq_file *)file->private_data)->private; |
| 44 | } |
| 45 | |
| 46 | /* |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 47 | * Determine the kernfs_ops for the given kernfs_node. This function must |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 48 | * be called while holding an active reference. |
| 49 | */ |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 50 | static const struct kernfs_ops *kernfs_ops(struct kernfs_node *kn) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 51 | { |
Tejun Heo | df23fc3 | 2013-12-11 14:11:56 -0500 | [diff] [blame] | 52 | if (kn->flags & KERNFS_LOCKDEP) |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 53 | lockdep_assert_held(kn); |
Tejun Heo | adc5e8b | 2013-12-11 14:11:54 -0500 | [diff] [blame] | 54 | return kn->attr.ops; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 55 | } |
| 56 | |
Tejun Heo | bb30594 | 2014-01-14 09:52:01 -0500 | [diff] [blame] | 57 | /* |
| 58 | * As kernfs_seq_stop() is also called after kernfs_seq_start() or |
| 59 | * kernfs_seq_next() failure, it needs to distinguish whether it's stopping |
| 60 | * a seq_file iteration which is fully initialized with an active reference |
| 61 | * or an aborted kernfs_seq_start() due to get_active failure. The |
| 62 | * position pointer is the only context for each seq_file iteration and |
| 63 | * thus the stop condition should be encoded in it. As the return value is |
| 64 | * directly visible to userland, ERR_PTR(-ENODEV) is the only acceptable |
| 65 | * choice to indicate get_active failure. |
| 66 | * |
| 67 | * Unfortunately, this is complicated due to the optional custom seq_file |
| 68 | * operations which may return ERR_PTR(-ENODEV) too. kernfs_seq_stop() |
| 69 | * can't distinguish whether ERR_PTR(-ENODEV) is from get_active failure or |
| 70 | * custom seq_file operations and thus can't decide whether put_active |
| 71 | * should be performed or not only on ERR_PTR(-ENODEV). |
| 72 | * |
| 73 | * This is worked around by factoring out the custom seq_stop() and |
| 74 | * put_active part into kernfs_seq_stop_active(), skipping it from |
| 75 | * kernfs_seq_stop() if ERR_PTR(-ENODEV) while invoking it directly after |
| 76 | * custom seq_file operations fail with ERR_PTR(-ENODEV) - this ensures |
| 77 | * that kernfs_seq_stop_active() is skipped only after get_active failure. |
| 78 | */ |
| 79 | static void kernfs_seq_stop_active(struct seq_file *sf, void *v) |
| 80 | { |
| 81 | struct kernfs_open_file *of = sf->private; |
| 82 | const struct kernfs_ops *ops = kernfs_ops(of->kn); |
| 83 | |
| 84 | if (ops->seq_stop) |
| 85 | ops->seq_stop(sf, v); |
| 86 | kernfs_put_active(of->kn); |
| 87 | } |
| 88 | |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 89 | static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos) |
| 90 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 91 | struct kernfs_open_file *of = sf->private; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 92 | const struct kernfs_ops *ops; |
| 93 | |
| 94 | /* |
| 95 | * @of->mutex nests outside active ref and is just to ensure that |
| 96 | * the ops aren't called concurrently for the same open file. |
| 97 | */ |
| 98 | mutex_lock(&of->mutex); |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 99 | if (!kernfs_get_active(of->kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 100 | return ERR_PTR(-ENODEV); |
| 101 | |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 102 | ops = kernfs_ops(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 103 | if (ops->seq_start) { |
Tejun Heo | bb30594 | 2014-01-14 09:52:01 -0500 | [diff] [blame] | 104 | void *next = ops->seq_start(sf, ppos); |
| 105 | /* see the comment above kernfs_seq_stop_active() */ |
| 106 | if (next == ERR_PTR(-ENODEV)) |
| 107 | kernfs_seq_stop_active(sf, next); |
| 108 | return next; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 109 | } else { |
| 110 | /* |
| 111 | * The same behavior and code as single_open(). Returns |
| 112 | * !NULL if pos is at the beginning; otherwise, NULL. |
| 113 | */ |
| 114 | return NULL + !*ppos; |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | static void *kernfs_seq_next(struct seq_file *sf, void *v, loff_t *ppos) |
| 119 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 120 | struct kernfs_open_file *of = sf->private; |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 121 | const struct kernfs_ops *ops = kernfs_ops(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 122 | |
| 123 | if (ops->seq_next) { |
Tejun Heo | bb30594 | 2014-01-14 09:52:01 -0500 | [diff] [blame] | 124 | void *next = ops->seq_next(sf, v, ppos); |
| 125 | /* see the comment above kernfs_seq_stop_active() */ |
| 126 | if (next == ERR_PTR(-ENODEV)) |
| 127 | kernfs_seq_stop_active(sf, next); |
| 128 | return next; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 129 | } else { |
| 130 | /* |
| 131 | * The same behavior and code as single_open(), always |
| 132 | * terminate after the initial read. |
| 133 | */ |
| 134 | ++*ppos; |
| 135 | return NULL; |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | static void kernfs_seq_stop(struct seq_file *sf, void *v) |
| 140 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 141 | struct kernfs_open_file *of = sf->private; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 142 | |
Tejun Heo | bb30594 | 2014-01-14 09:52:01 -0500 | [diff] [blame] | 143 | if (v != ERR_PTR(-ENODEV)) |
| 144 | kernfs_seq_stop_active(sf, v); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 145 | mutex_unlock(&of->mutex); |
| 146 | } |
| 147 | |
| 148 | static int kernfs_seq_show(struct seq_file *sf, void *v) |
| 149 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 150 | struct kernfs_open_file *of = sf->private; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 151 | |
Tejun Heo | adc5e8b | 2013-12-11 14:11:54 -0500 | [diff] [blame] | 152 | of->event = atomic_read(&of->kn->attr.open->event); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 153 | |
Tejun Heo | adc5e8b | 2013-12-11 14:11:54 -0500 | [diff] [blame] | 154 | return of->kn->attr.ops->seq_show(sf, v); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 155 | } |
| 156 | |
| 157 | static const struct seq_operations kernfs_seq_ops = { |
| 158 | .start = kernfs_seq_start, |
| 159 | .next = kernfs_seq_next, |
| 160 | .stop = kernfs_seq_stop, |
| 161 | .show = kernfs_seq_show, |
| 162 | }; |
| 163 | |
| 164 | /* |
| 165 | * As reading a bin file can have side-effects, the exact offset and bytes |
| 166 | * specified in read(2) call should be passed to the read callback making |
| 167 | * it difficult to use seq_file. Implement simplistic custom buffering for |
| 168 | * bin files. |
| 169 | */ |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 170 | static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of, |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 171 | char __user *user_buf, size_t count, |
| 172 | loff_t *ppos) |
| 173 | { |
| 174 | ssize_t len = min_t(size_t, count, PAGE_SIZE); |
| 175 | const struct kernfs_ops *ops; |
| 176 | char *buf; |
| 177 | |
| 178 | buf = kmalloc(len, GFP_KERNEL); |
| 179 | if (!buf) |
| 180 | return -ENOMEM; |
| 181 | |
| 182 | /* |
| 183 | * @of->mutex nests outside active ref and is just to ensure that |
| 184 | * the ops aren't called concurrently for the same open file. |
| 185 | */ |
| 186 | mutex_lock(&of->mutex); |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 187 | if (!kernfs_get_active(of->kn)) { |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 188 | len = -ENODEV; |
| 189 | mutex_unlock(&of->mutex); |
| 190 | goto out_free; |
| 191 | } |
| 192 | |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 193 | ops = kernfs_ops(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 194 | if (ops->read) |
| 195 | len = ops->read(of, buf, len, *ppos); |
| 196 | else |
| 197 | len = -EINVAL; |
| 198 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 199 | kernfs_put_active(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 200 | mutex_unlock(&of->mutex); |
| 201 | |
| 202 | if (len < 0) |
| 203 | goto out_free; |
| 204 | |
| 205 | if (copy_to_user(user_buf, buf, len)) { |
| 206 | len = -EFAULT; |
| 207 | goto out_free; |
| 208 | } |
| 209 | |
| 210 | *ppos += len; |
| 211 | |
| 212 | out_free: |
| 213 | kfree(buf); |
| 214 | return len; |
| 215 | } |
| 216 | |
| 217 | /** |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 218 | * kernfs_fop_read - kernfs vfs read callback |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 219 | * @file: file pointer |
| 220 | * @user_buf: data to write |
| 221 | * @count: number of bytes |
| 222 | * @ppos: starting offset |
| 223 | */ |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 224 | static ssize_t kernfs_fop_read(struct file *file, char __user *user_buf, |
| 225 | size_t count, loff_t *ppos) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 226 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 227 | struct kernfs_open_file *of = kernfs_of(file); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 228 | |
Tejun Heo | df23fc3 | 2013-12-11 14:11:56 -0500 | [diff] [blame] | 229 | if (of->kn->flags & KERNFS_HAS_SEQ_SHOW) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 230 | return seq_read(file, user_buf, count, ppos); |
| 231 | else |
| 232 | return kernfs_file_direct_read(of, user_buf, count, ppos); |
| 233 | } |
| 234 | |
| 235 | /** |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 236 | * kernfs_fop_write - kernfs vfs write callback |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 237 | * @file: file pointer |
| 238 | * @user_buf: data to write |
| 239 | * @count: number of bytes |
| 240 | * @ppos: starting offset |
| 241 | * |
| 242 | * Copy data in from userland and pass it to the matching kernfs write |
| 243 | * operation. |
| 244 | * |
| 245 | * There is no easy way for us to know if userspace is only doing a partial |
| 246 | * write, so we don't support them. We expect the entire buffer to come on |
| 247 | * the first write. Hint: if you're writing a value, first read the file, |
| 248 | * modify only the the value you're changing, then write entire buffer |
| 249 | * back. |
| 250 | */ |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 251 | static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, |
| 252 | size_t count, loff_t *ppos) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 253 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 254 | struct kernfs_open_file *of = kernfs_of(file); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 255 | const struct kernfs_ops *ops; |
Tejun Heo | b7ce40c | 2014-03-04 15:38:46 -0500 | [diff] [blame] | 256 | size_t len; |
| 257 | char *buf; |
| 258 | |
| 259 | if (of->atomic_write_len) { |
| 260 | len = count; |
| 261 | if (len > of->atomic_write_len) |
| 262 | return -E2BIG; |
| 263 | } else { |
| 264 | len = min_t(size_t, count, PAGE_SIZE); |
| 265 | } |
| 266 | |
| 267 | buf = kmalloc(len + 1, GFP_KERNEL); |
| 268 | if (!buf) |
| 269 | return -ENOMEM; |
| 270 | |
| 271 | if (copy_from_user(buf, user_buf, len)) { |
| 272 | len = -EFAULT; |
| 273 | goto out_free; |
| 274 | } |
| 275 | buf[len] = '\0'; /* guarantee string termination */ |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 276 | |
| 277 | /* |
| 278 | * @of->mutex nests outside active ref and is just to ensure that |
| 279 | * the ops aren't called concurrently for the same open file. |
| 280 | */ |
| 281 | mutex_lock(&of->mutex); |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 282 | if (!kernfs_get_active(of->kn)) { |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 283 | mutex_unlock(&of->mutex); |
Tejun Heo | b7ce40c | 2014-03-04 15:38:46 -0500 | [diff] [blame] | 284 | len = -ENODEV; |
| 285 | goto out_free; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 286 | } |
| 287 | |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 288 | ops = kernfs_ops(of->kn); |
Tejun Heo | b7ce40c | 2014-03-04 15:38:46 -0500 | [diff] [blame] | 289 | if (ops->write) |
| 290 | len = ops->write(of, buf, len, *ppos); |
| 291 | else |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 292 | len = -EINVAL; |
| 293 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 294 | kernfs_put_active(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 295 | mutex_unlock(&of->mutex); |
| 296 | |
| 297 | if (len > 0) |
| 298 | *ppos += len; |
Tejun Heo | b7ce40c | 2014-03-04 15:38:46 -0500 | [diff] [blame] | 299 | out_free: |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 300 | kfree(buf); |
| 301 | return len; |
| 302 | } |
| 303 | |
| 304 | static void kernfs_vma_open(struct vm_area_struct *vma) |
| 305 | { |
| 306 | struct file *file = vma->vm_file; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 307 | struct kernfs_open_file *of = kernfs_of(file); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 308 | |
| 309 | if (!of->vm_ops) |
| 310 | return; |
| 311 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 312 | if (!kernfs_get_active(of->kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 313 | return; |
| 314 | |
| 315 | if (of->vm_ops->open) |
| 316 | of->vm_ops->open(vma); |
| 317 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 318 | kernfs_put_active(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 319 | } |
| 320 | |
| 321 | static int kernfs_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| 322 | { |
| 323 | struct file *file = vma->vm_file; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 324 | struct kernfs_open_file *of = kernfs_of(file); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 325 | int ret; |
| 326 | |
| 327 | if (!of->vm_ops) |
| 328 | return VM_FAULT_SIGBUS; |
| 329 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 330 | if (!kernfs_get_active(of->kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 331 | return VM_FAULT_SIGBUS; |
| 332 | |
| 333 | ret = VM_FAULT_SIGBUS; |
| 334 | if (of->vm_ops->fault) |
| 335 | ret = of->vm_ops->fault(vma, vmf); |
| 336 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 337 | kernfs_put_active(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 338 | return ret; |
| 339 | } |
| 340 | |
| 341 | static int kernfs_vma_page_mkwrite(struct vm_area_struct *vma, |
| 342 | struct vm_fault *vmf) |
| 343 | { |
| 344 | struct file *file = vma->vm_file; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 345 | struct kernfs_open_file *of = kernfs_of(file); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 346 | int ret; |
| 347 | |
| 348 | if (!of->vm_ops) |
| 349 | return VM_FAULT_SIGBUS; |
| 350 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 351 | if (!kernfs_get_active(of->kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 352 | return VM_FAULT_SIGBUS; |
| 353 | |
| 354 | ret = 0; |
| 355 | if (of->vm_ops->page_mkwrite) |
| 356 | ret = of->vm_ops->page_mkwrite(vma, vmf); |
| 357 | else |
| 358 | file_update_time(file); |
| 359 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 360 | kernfs_put_active(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 361 | return ret; |
| 362 | } |
| 363 | |
| 364 | static int kernfs_vma_access(struct vm_area_struct *vma, unsigned long addr, |
| 365 | void *buf, int len, int write) |
| 366 | { |
| 367 | struct file *file = vma->vm_file; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 368 | struct kernfs_open_file *of = kernfs_of(file); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 369 | int ret; |
| 370 | |
| 371 | if (!of->vm_ops) |
| 372 | return -EINVAL; |
| 373 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 374 | if (!kernfs_get_active(of->kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 375 | return -EINVAL; |
| 376 | |
| 377 | ret = -EINVAL; |
| 378 | if (of->vm_ops->access) |
| 379 | ret = of->vm_ops->access(vma, addr, buf, len, write); |
| 380 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 381 | kernfs_put_active(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 382 | return ret; |
| 383 | } |
| 384 | |
| 385 | #ifdef CONFIG_NUMA |
| 386 | static int kernfs_vma_set_policy(struct vm_area_struct *vma, |
| 387 | struct mempolicy *new) |
| 388 | { |
| 389 | struct file *file = vma->vm_file; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 390 | struct kernfs_open_file *of = kernfs_of(file); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 391 | int ret; |
| 392 | |
| 393 | if (!of->vm_ops) |
| 394 | return 0; |
| 395 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 396 | if (!kernfs_get_active(of->kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 397 | return -EINVAL; |
| 398 | |
| 399 | ret = 0; |
| 400 | if (of->vm_ops->set_policy) |
| 401 | ret = of->vm_ops->set_policy(vma, new); |
| 402 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 403 | kernfs_put_active(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 404 | return ret; |
| 405 | } |
| 406 | |
| 407 | static struct mempolicy *kernfs_vma_get_policy(struct vm_area_struct *vma, |
| 408 | unsigned long addr) |
| 409 | { |
| 410 | struct file *file = vma->vm_file; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 411 | struct kernfs_open_file *of = kernfs_of(file); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 412 | struct mempolicy *pol; |
| 413 | |
| 414 | if (!of->vm_ops) |
| 415 | return vma->vm_policy; |
| 416 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 417 | if (!kernfs_get_active(of->kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 418 | return vma->vm_policy; |
| 419 | |
| 420 | pol = vma->vm_policy; |
| 421 | if (of->vm_ops->get_policy) |
| 422 | pol = of->vm_ops->get_policy(vma, addr); |
| 423 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 424 | kernfs_put_active(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 425 | return pol; |
| 426 | } |
| 427 | |
| 428 | static int kernfs_vma_migrate(struct vm_area_struct *vma, |
| 429 | const nodemask_t *from, const nodemask_t *to, |
| 430 | unsigned long flags) |
| 431 | { |
| 432 | struct file *file = vma->vm_file; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 433 | struct kernfs_open_file *of = kernfs_of(file); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 434 | int ret; |
| 435 | |
| 436 | if (!of->vm_ops) |
| 437 | return 0; |
| 438 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 439 | if (!kernfs_get_active(of->kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 440 | return 0; |
| 441 | |
| 442 | ret = 0; |
| 443 | if (of->vm_ops->migrate) |
| 444 | ret = of->vm_ops->migrate(vma, from, to, flags); |
| 445 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 446 | kernfs_put_active(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 447 | return ret; |
| 448 | } |
| 449 | #endif |
| 450 | |
| 451 | static const struct vm_operations_struct kernfs_vm_ops = { |
| 452 | .open = kernfs_vma_open, |
| 453 | .fault = kernfs_vma_fault, |
| 454 | .page_mkwrite = kernfs_vma_page_mkwrite, |
| 455 | .access = kernfs_vma_access, |
| 456 | #ifdef CONFIG_NUMA |
| 457 | .set_policy = kernfs_vma_set_policy, |
| 458 | .get_policy = kernfs_vma_get_policy, |
| 459 | .migrate = kernfs_vma_migrate, |
| 460 | #endif |
| 461 | }; |
| 462 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 463 | static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 464 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 465 | struct kernfs_open_file *of = kernfs_of(file); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 466 | const struct kernfs_ops *ops; |
| 467 | int rc; |
| 468 | |
Tejun Heo | 9b2db6e | 2013-12-10 09:29:17 -0500 | [diff] [blame] | 469 | /* |
| 470 | * mmap path and of->mutex are prone to triggering spurious lockdep |
| 471 | * warnings and we don't want to add spurious locking dependency |
| 472 | * between the two. Check whether mmap is actually implemented |
| 473 | * without grabbing @of->mutex by testing HAS_MMAP flag. See the |
| 474 | * comment in kernfs_file_open() for more details. |
| 475 | */ |
Tejun Heo | df23fc3 | 2013-12-11 14:11:56 -0500 | [diff] [blame] | 476 | if (!(of->kn->flags & KERNFS_HAS_MMAP)) |
Tejun Heo | 9b2db6e | 2013-12-10 09:29:17 -0500 | [diff] [blame] | 477 | return -ENODEV; |
| 478 | |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 479 | mutex_lock(&of->mutex); |
| 480 | |
| 481 | rc = -ENODEV; |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 482 | if (!kernfs_get_active(of->kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 483 | goto out_unlock; |
| 484 | |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 485 | ops = kernfs_ops(of->kn); |
Tejun Heo | 9b2db6e | 2013-12-10 09:29:17 -0500 | [diff] [blame] | 486 | rc = ops->mmap(of, vma); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 487 | |
| 488 | /* |
| 489 | * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup() |
| 490 | * to satisfy versions of X which crash if the mmap fails: that |
| 491 | * substitutes a new vm_file, and we don't then want bin_vm_ops. |
| 492 | */ |
| 493 | if (vma->vm_file != file) |
| 494 | goto out_put; |
| 495 | |
| 496 | rc = -EINVAL; |
| 497 | if (of->mmapped && of->vm_ops != vma->vm_ops) |
| 498 | goto out_put; |
| 499 | |
| 500 | /* |
| 501 | * It is not possible to successfully wrap close. |
| 502 | * So error if someone is trying to use close. |
| 503 | */ |
| 504 | rc = -EINVAL; |
| 505 | if (vma->vm_ops && vma->vm_ops->close) |
| 506 | goto out_put; |
| 507 | |
| 508 | rc = 0; |
| 509 | of->mmapped = 1; |
| 510 | of->vm_ops = vma->vm_ops; |
| 511 | vma->vm_ops = &kernfs_vm_ops; |
| 512 | out_put: |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 513 | kernfs_put_active(of->kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 514 | out_unlock: |
| 515 | mutex_unlock(&of->mutex); |
| 516 | |
| 517 | return rc; |
| 518 | } |
| 519 | |
| 520 | /** |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 521 | * kernfs_get_open_node - get or create kernfs_open_node |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 522 | * @kn: target kernfs_node |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 523 | * @of: kernfs_open_file for this instance of open |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 524 | * |
Tejun Heo | adc5e8b | 2013-12-11 14:11:54 -0500 | [diff] [blame] | 525 | * If @kn->attr.open exists, increment its reference count; otherwise, |
| 526 | * create one. @of is chained to the files list. |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 527 | * |
| 528 | * LOCKING: |
| 529 | * Kernel thread context (may sleep). |
| 530 | * |
| 531 | * RETURNS: |
| 532 | * 0 on success, -errno on failure. |
| 533 | */ |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 534 | static int kernfs_get_open_node(struct kernfs_node *kn, |
| 535 | struct kernfs_open_file *of) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 536 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 537 | struct kernfs_open_node *on, *new_on = NULL; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 538 | |
| 539 | retry: |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 540 | mutex_lock(&kernfs_open_file_mutex); |
| 541 | spin_lock_irq(&kernfs_open_node_lock); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 542 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 543 | if (!kn->attr.open && new_on) { |
| 544 | kn->attr.open = new_on; |
| 545 | new_on = NULL; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 546 | } |
| 547 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 548 | on = kn->attr.open; |
| 549 | if (on) { |
| 550 | atomic_inc(&on->refcnt); |
| 551 | list_add_tail(&of->list, &on->files); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 552 | } |
| 553 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 554 | spin_unlock_irq(&kernfs_open_node_lock); |
| 555 | mutex_unlock(&kernfs_open_file_mutex); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 556 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 557 | if (on) { |
| 558 | kfree(new_on); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 559 | return 0; |
| 560 | } |
| 561 | |
| 562 | /* not there, initialize a new one and retry */ |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 563 | new_on = kmalloc(sizeof(*new_on), GFP_KERNEL); |
| 564 | if (!new_on) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 565 | return -ENOMEM; |
| 566 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 567 | atomic_set(&new_on->refcnt, 0); |
| 568 | atomic_set(&new_on->event, 1); |
| 569 | init_waitqueue_head(&new_on->poll); |
| 570 | INIT_LIST_HEAD(&new_on->files); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 571 | goto retry; |
| 572 | } |
| 573 | |
| 574 | /** |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 575 | * kernfs_put_open_node - put kernfs_open_node |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 576 | * @kn: target kernfs_nodet |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 577 | * @of: associated kernfs_open_file |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 578 | * |
Tejun Heo | adc5e8b | 2013-12-11 14:11:54 -0500 | [diff] [blame] | 579 | * Put @kn->attr.open and unlink @of from the files list. If |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 580 | * reference count reaches zero, disassociate and free it. |
| 581 | * |
| 582 | * LOCKING: |
| 583 | * None. |
| 584 | */ |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 585 | static void kernfs_put_open_node(struct kernfs_node *kn, |
| 586 | struct kernfs_open_file *of) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 587 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 588 | struct kernfs_open_node *on = kn->attr.open; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 589 | unsigned long flags; |
| 590 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 591 | mutex_lock(&kernfs_open_file_mutex); |
| 592 | spin_lock_irqsave(&kernfs_open_node_lock, flags); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 593 | |
| 594 | if (of) |
| 595 | list_del(&of->list); |
| 596 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 597 | if (atomic_dec_and_test(&on->refcnt)) |
Tejun Heo | adc5e8b | 2013-12-11 14:11:54 -0500 | [diff] [blame] | 598 | kn->attr.open = NULL; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 599 | else |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 600 | on = NULL; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 601 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 602 | spin_unlock_irqrestore(&kernfs_open_node_lock, flags); |
| 603 | mutex_unlock(&kernfs_open_file_mutex); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 604 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 605 | kfree(on); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 606 | } |
| 607 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 608 | static int kernfs_fop_open(struct inode *inode, struct file *file) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 609 | { |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 610 | struct kernfs_node *kn = file->f_path.dentry->d_fsdata; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 611 | const struct kernfs_ops *ops; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 612 | struct kernfs_open_file *of; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 613 | bool has_read, has_write, has_mmap; |
| 614 | int error = -EACCES; |
| 615 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 616 | if (!kernfs_get_active(kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 617 | return -ENODEV; |
| 618 | |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 619 | ops = kernfs_ops(kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 620 | |
| 621 | has_read = ops->seq_show || ops->read || ops->mmap; |
| 622 | has_write = ops->write || ops->mmap; |
| 623 | has_mmap = ops->mmap; |
| 624 | |
| 625 | /* check perms and supported operations */ |
| 626 | if ((file->f_mode & FMODE_WRITE) && |
| 627 | (!(inode->i_mode & S_IWUGO) || !has_write)) |
| 628 | goto err_out; |
| 629 | |
| 630 | if ((file->f_mode & FMODE_READ) && |
| 631 | (!(inode->i_mode & S_IRUGO) || !has_read)) |
| 632 | goto err_out; |
| 633 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 634 | /* allocate a kernfs_open_file for the file */ |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 635 | error = -ENOMEM; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 636 | of = kzalloc(sizeof(struct kernfs_open_file), GFP_KERNEL); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 637 | if (!of) |
| 638 | goto err_out; |
| 639 | |
| 640 | /* |
| 641 | * The following is done to give a different lockdep key to |
| 642 | * @of->mutex for files which implement mmap. This is a rather |
| 643 | * crude way to avoid false positive lockdep warning around |
| 644 | * mm->mmap_sem - mmap nests @of->mutex under mm->mmap_sem and |
| 645 | * reading /sys/block/sda/trace/act_mask grabs sr_mutex, under |
| 646 | * which mm->mmap_sem nests, while holding @of->mutex. As each |
| 647 | * open file has a separate mutex, it's okay as long as those don't |
| 648 | * happen on the same file. At this point, we can't easily give |
| 649 | * each file a separate locking class. Let's differentiate on |
| 650 | * whether the file has mmap or not for now. |
Tejun Heo | 9b2db6e | 2013-12-10 09:29:17 -0500 | [diff] [blame] | 651 | * |
| 652 | * Both paths of the branch look the same. They're supposed to |
| 653 | * look that way and give @of->mutex different static lockdep keys. |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 654 | */ |
| 655 | if (has_mmap) |
| 656 | mutex_init(&of->mutex); |
| 657 | else |
| 658 | mutex_init(&of->mutex); |
| 659 | |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 660 | of->kn = kn; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 661 | of->file = file; |
| 662 | |
| 663 | /* |
Tejun Heo | b7ce40c | 2014-03-04 15:38:46 -0500 | [diff] [blame] | 664 | * Write path needs to atomic_write_len outside active reference. |
| 665 | * Cache it in open_file. See kernfs_fop_write() for details. |
| 666 | */ |
| 667 | of->atomic_write_len = ops->atomic_write_len; |
| 668 | |
| 669 | /* |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 670 | * Always instantiate seq_file even if read access doesn't use |
| 671 | * seq_file or is not requested. This unifies private data access |
| 672 | * and readable regular files are the vast majority anyway. |
| 673 | */ |
| 674 | if (ops->seq_show) |
| 675 | error = seq_open(file, &kernfs_seq_ops); |
| 676 | else |
| 677 | error = seq_open(file, NULL); |
| 678 | if (error) |
| 679 | goto err_free; |
| 680 | |
| 681 | ((struct seq_file *)file->private_data)->private = of; |
| 682 | |
| 683 | /* seq_file clears PWRITE unconditionally, restore it if WRITE */ |
| 684 | if (file->f_mode & FMODE_WRITE) |
| 685 | file->f_mode |= FMODE_PWRITE; |
| 686 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 687 | /* make sure we have open node struct */ |
| 688 | error = kernfs_get_open_node(kn, of); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 689 | if (error) |
| 690 | goto err_close; |
| 691 | |
| 692 | /* open succeeded, put active references */ |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 693 | kernfs_put_active(kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 694 | return 0; |
| 695 | |
| 696 | err_close: |
| 697 | seq_release(inode, file); |
| 698 | err_free: |
| 699 | kfree(of); |
| 700 | err_out: |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 701 | kernfs_put_active(kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 702 | return error; |
| 703 | } |
| 704 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 705 | static int kernfs_fop_release(struct inode *inode, struct file *filp) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 706 | { |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 707 | struct kernfs_node *kn = filp->f_path.dentry->d_fsdata; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 708 | struct kernfs_open_file *of = kernfs_of(filp); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 709 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 710 | kernfs_put_open_node(kn, of); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 711 | seq_release(inode, filp); |
| 712 | kfree(of); |
| 713 | |
| 714 | return 0; |
| 715 | } |
| 716 | |
Greg Kroah-Hartman | 55f6e30 | 2014-01-13 14:27:16 -0800 | [diff] [blame] | 717 | void kernfs_unmap_bin_file(struct kernfs_node *kn) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 718 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 719 | struct kernfs_open_node *on; |
| 720 | struct kernfs_open_file *of; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 721 | |
Greg Kroah-Hartman | 55f6e30 | 2014-01-13 14:27:16 -0800 | [diff] [blame] | 722 | if (!(kn->flags & KERNFS_HAS_MMAP)) |
| 723 | return; |
| 724 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 725 | spin_lock_irq(&kernfs_open_node_lock); |
| 726 | on = kn->attr.open; |
| 727 | if (on) |
| 728 | atomic_inc(&on->refcnt); |
| 729 | spin_unlock_irq(&kernfs_open_node_lock); |
| 730 | if (!on) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 731 | return; |
| 732 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 733 | mutex_lock(&kernfs_open_file_mutex); |
| 734 | list_for_each_entry(of, &on->files, list) { |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 735 | struct inode *inode = file_inode(of->file); |
| 736 | unmap_mapping_range(inode->i_mapping, 0, 0, 1); |
| 737 | } |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 738 | mutex_unlock(&kernfs_open_file_mutex); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 739 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 740 | kernfs_put_open_node(kn, NULL); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 741 | } |
| 742 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 743 | /* |
| 744 | * Kernfs attribute files are pollable. The idea is that you read |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 745 | * the content and then you use 'poll' or 'select' to wait for |
| 746 | * the content to change. When the content changes (assuming the |
| 747 | * manager for the kobject supports notification), poll will |
| 748 | * return POLLERR|POLLPRI, and select will return the fd whether |
| 749 | * it is waiting for read, write, or exceptions. |
| 750 | * Once poll/select indicates that the value has changed, you |
| 751 | * need to close and re-open the file, or seek to 0 and read again. |
| 752 | * Reminder: this only works for attributes which actively support |
| 753 | * it, and it is not possible to test an attribute from userspace |
| 754 | * to see if it supports poll (Neither 'poll' nor 'select' return |
| 755 | * an appropriate error code). When in doubt, set a suitable timeout value. |
| 756 | */ |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 757 | static unsigned int kernfs_fop_poll(struct file *filp, poll_table *wait) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 758 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 759 | struct kernfs_open_file *of = kernfs_of(filp); |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 760 | struct kernfs_node *kn = filp->f_path.dentry->d_fsdata; |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 761 | struct kernfs_open_node *on = kn->attr.open; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 762 | |
| 763 | /* need parent for the kobj, grab both */ |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 764 | if (!kernfs_get_active(kn)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 765 | goto trigger; |
| 766 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 767 | poll_wait(filp, &on->poll, wait); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 768 | |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 769 | kernfs_put_active(kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 770 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 771 | if (of->event != atomic_read(&on->event)) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 772 | goto trigger; |
| 773 | |
| 774 | return DEFAULT_POLLMASK; |
| 775 | |
| 776 | trigger: |
| 777 | return DEFAULT_POLLMASK|POLLERR|POLLPRI; |
| 778 | } |
| 779 | |
| 780 | /** |
| 781 | * kernfs_notify - notify a kernfs file |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 782 | * @kn: file to notify |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 783 | * |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 784 | * Notify @kn such that poll(2) on @kn wakes up. |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 785 | */ |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 786 | void kernfs_notify(struct kernfs_node *kn) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 787 | { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 788 | struct kernfs_open_node *on; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 789 | unsigned long flags; |
| 790 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 791 | spin_lock_irqsave(&kernfs_open_node_lock, flags); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 792 | |
Tejun Heo | df23fc3 | 2013-12-11 14:11:56 -0500 | [diff] [blame] | 793 | if (!WARN_ON(kernfs_type(kn) != KERNFS_FILE)) { |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 794 | on = kn->attr.open; |
| 795 | if (on) { |
| 796 | atomic_inc(&on->event); |
| 797 | wake_up_interruptible(&on->poll); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 798 | } |
| 799 | } |
| 800 | |
Tejun Heo | c525aad | 2013-12-11 14:11:55 -0500 | [diff] [blame] | 801 | spin_unlock_irqrestore(&kernfs_open_node_lock, flags); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 802 | } |
| 803 | EXPORT_SYMBOL_GPL(kernfs_notify); |
| 804 | |
Tejun Heo | a797bfc | 2013-12-11 14:11:57 -0500 | [diff] [blame] | 805 | const struct file_operations kernfs_file_fops = { |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 806 | .read = kernfs_fop_read, |
| 807 | .write = kernfs_fop_write, |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 808 | .llseek = generic_file_llseek, |
Tejun Heo | c637b8a | 2013-12-11 14:11:58 -0500 | [diff] [blame] | 809 | .mmap = kernfs_fop_mmap, |
| 810 | .open = kernfs_fop_open, |
| 811 | .release = kernfs_fop_release, |
| 812 | .poll = kernfs_fop_poll, |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 813 | }; |
| 814 | |
| 815 | /** |
Tejun Heo | 2063d60 | 2013-12-11 16:02:57 -0500 | [diff] [blame] | 816 | * __kernfs_create_file - kernfs internal function to create a file |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 817 | * @parent: directory to create the file in |
| 818 | * @name: name of the file |
| 819 | * @mode: mode of the file |
| 820 | * @size: size of the file |
| 821 | * @ops: kernfs operations for the file |
| 822 | * @priv: private data for the file |
| 823 | * @ns: optional namespace tag of the file |
Tejun Heo | 2063d60 | 2013-12-11 16:02:57 -0500 | [diff] [blame] | 824 | * @static_name: don't copy file name |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 825 | * @key: lockdep key for the file's active_ref, %NULL to disable lockdep |
| 826 | * |
| 827 | * Returns the created node on success, ERR_PTR() value on error. |
| 828 | */ |
Tejun Heo | 2063d60 | 2013-12-11 16:02:57 -0500 | [diff] [blame] | 829 | struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, |
| 830 | const char *name, |
| 831 | umode_t mode, loff_t size, |
| 832 | const struct kernfs_ops *ops, |
| 833 | void *priv, const void *ns, |
| 834 | bool name_is_static, |
| 835 | struct lock_class_key *key) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 836 | { |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 837 | struct kernfs_node *kn; |
Tejun Heo | 2063d60 | 2013-12-11 16:02:57 -0500 | [diff] [blame] | 838 | unsigned flags; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 839 | int rc; |
| 840 | |
Tejun Heo | 2063d60 | 2013-12-11 16:02:57 -0500 | [diff] [blame] | 841 | flags = KERNFS_FILE; |
| 842 | if (name_is_static) |
| 843 | flags |= KERNFS_STATIC_NAME; |
| 844 | |
Tejun Heo | db4aad2 | 2014-01-17 09:58:25 -0500 | [diff] [blame] | 845 | kn = kernfs_new_node(parent, name, (mode & S_IALLUGO) | S_IFREG, flags); |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 846 | if (!kn) |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 847 | return ERR_PTR(-ENOMEM); |
| 848 | |
Tejun Heo | adc5e8b | 2013-12-11 14:11:54 -0500 | [diff] [blame] | 849 | kn->attr.ops = ops; |
| 850 | kn->attr.size = size; |
| 851 | kn->ns = ns; |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 852 | kn->priv = priv; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 853 | |
| 854 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 855 | if (key) { |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 856 | lockdep_init_map(&kn->dep_map, "s_active", key, 0); |
Tejun Heo | df23fc3 | 2013-12-11 14:11:56 -0500 | [diff] [blame] | 857 | kn->flags |= KERNFS_LOCKDEP; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 858 | } |
| 859 | #endif |
| 860 | |
| 861 | /* |
Tejun Heo | adc5e8b | 2013-12-11 14:11:54 -0500 | [diff] [blame] | 862 | * kn->attr.ops is accesible only while holding active ref. We |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 863 | * need to know whether some ops are implemented outside active |
| 864 | * ref. Cache their existence in flags. |
| 865 | */ |
| 866 | if (ops->seq_show) |
Tejun Heo | df23fc3 | 2013-12-11 14:11:56 -0500 | [diff] [blame] | 867 | kn->flags |= KERNFS_HAS_SEQ_SHOW; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 868 | if (ops->mmap) |
Tejun Heo | df23fc3 | 2013-12-11 14:11:56 -0500 | [diff] [blame] | 869 | kn->flags |= KERNFS_HAS_MMAP; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 870 | |
Tejun Heo | 988cd7a | 2014-02-03 14:02:58 -0500 | [diff] [blame] | 871 | rc = kernfs_add_one(kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 872 | if (rc) { |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 873 | kernfs_put(kn); |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 874 | return ERR_PTR(rc); |
| 875 | } |
Tejun Heo | 324a56e | 2013-12-11 14:11:53 -0500 | [diff] [blame] | 876 | return kn; |
Tejun Heo | 414985a | 2013-11-28 14:54:34 -0500 | [diff] [blame] | 877 | } |