Contents of /trunk/kernel26-magellan/patches-2.6.16-r12/0114-2.6.16.12-proc.patch
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Mon Jun 5 09:25:38 2006 UTC (18 years, 3 months ago) by niro
File size: 13636 byte(s)
Mon Jun 5 09:25:38 2006 UTC (18 years, 3 months ago) by niro
File size: 13636 byte(s)
ver bump to 2.6.16-r12: - updated to linux-2.6.16.19 - updated to ck11
1 | From: Andrew Morton <akpm@osdl.org> |
2 | Date: Fri, 21 Apr 2006 08:51:36 +0000 (-0700) |
3 | Subject: [PATCH] Simplify proc/devices and fix early termination regression |
4 | X-Git-Url: http://www.kernel.org/git/?p=linux/kernel/git/stable/linux-2.6.16.y.git;a=commitdiff;h=692c0509fd0719406f8f781d9a9f2e19aa6b7c0a |
5 | |
6 | [PATCH] Simplify proc/devices and fix early termination regression |
7 | |
8 | Repair /proc/devices early-termination regression. |
9 | |
10 | 2.6.16 broke /proc/devices. An application often gets an |
11 | EOF before the end of data is reached, if that application |
12 | uses a series of short read(2)s to access the data. I have |
13 | used read buffers of varying sizes with varying degrees |
14 | of unsuccess (larger sizes get further into the data than |
15 | smaller sizes, following a simple pattern). It appears |
16 | that the only safe way to get the data is to use a single |
17 | read buffer larger than all the data in /proc/devices. |
18 | |
19 | The following example demonstates the problem: |
20 | |
21 | # dd if=/proc/devices bs=1 |
22 | Character devices: |
23 | 1 mem |
24 | 27+0 records in |
25 | 27+0 records out |
26 | |
27 | This patch is a backport of the fix recently accepted to |
28 | Linus's tree: |
29 | |
30 | commit 68eef3b4791572ecb70249c7fb145bb3742dd899 |
31 | [PATCH] Simplify proc/devices and fix early termination regression |
32 | |
33 | It replaces the complex, state-machine algorithm introduced |
34 | in 2.6.16 with a simple algorithm, modeled on the implementation |
35 | of /proc/interrupts. |
36 | |
37 | [akpm@osdl.org: cleanups, simplifications] |
38 | |
39 | Signed-off-by: Joe Korty <joe.korty@ccur.com> |
40 | Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
41 | --- |
42 | |
43 | --- a/block/genhd.c |
44 | +++ b/block/genhd.c |
45 | @@ -16,8 +16,6 @@ |
46 | #include <linux/kobj_map.h> |
47 | #include <linux/buffer_head.h> |
48 | |
49 | -#define MAX_PROBE_HASH 255 /* random */ |
50 | - |
51 | static struct subsystem block_subsys; |
52 | |
53 | static DECLARE_MUTEX(block_subsys_sem); |
54 | @@ -30,108 +28,29 @@ static struct blk_major_name { |
55 | struct blk_major_name *next; |
56 | int major; |
57 | char name[16]; |
58 | -} *major_names[MAX_PROBE_HASH]; |
59 | +} *major_names[BLKDEV_MAJOR_HASH_SIZE]; |
60 | |
61 | /* index in the above - for now: assume no multimajor ranges */ |
62 | static inline int major_to_index(int major) |
63 | { |
64 | - return major % MAX_PROBE_HASH; |
65 | -} |
66 | - |
67 | -struct blkdev_info { |
68 | - int index; |
69 | - struct blk_major_name *bd; |
70 | -}; |
71 | - |
72 | -/* |
73 | - * iterate over a list of blkdev_info structures. allows |
74 | - * the major_names array to be iterated over from outside this file |
75 | - * must be called with the block_subsys_sem held |
76 | - */ |
77 | -void *get_next_blkdev(void *dev) |
78 | -{ |
79 | - struct blkdev_info *info; |
80 | - |
81 | - if (dev == NULL) { |
82 | - info = kmalloc(sizeof(*info), GFP_KERNEL); |
83 | - if (!info) |
84 | - goto out; |
85 | - info->index=0; |
86 | - info->bd = major_names[info->index]; |
87 | - if (info->bd) |
88 | - goto out; |
89 | - } else { |
90 | - info = dev; |
91 | - } |
92 | - |
93 | - while (info->index < ARRAY_SIZE(major_names)) { |
94 | - if (info->bd) |
95 | - info->bd = info->bd->next; |
96 | - if (info->bd) |
97 | - goto out; |
98 | - /* |
99 | - * No devices on this chain, move to the next |
100 | - */ |
101 | - info->index++; |
102 | - info->bd = (info->index < ARRAY_SIZE(major_names)) ? |
103 | - major_names[info->index] : NULL; |
104 | - if (info->bd) |
105 | - goto out; |
106 | - } |
107 | - |
108 | -out: |
109 | - return info; |
110 | -} |
111 | - |
112 | -void *acquire_blkdev_list(void) |
113 | -{ |
114 | - down(&block_subsys_sem); |
115 | - return get_next_blkdev(NULL); |
116 | -} |
117 | - |
118 | -void release_blkdev_list(void *dev) |
119 | -{ |
120 | - up(&block_subsys_sem); |
121 | - kfree(dev); |
122 | + return major % BLKDEV_MAJOR_HASH_SIZE; |
123 | } |
124 | |
125 | +#ifdef CONFIG_PROC_FS |
126 | |
127 | -/* |
128 | - * Count the number of records in the blkdev_list. |
129 | - * must be called with the block_subsys_sem held |
130 | - */ |
131 | -int count_blkdev_list(void) |
132 | +void blkdev_show(struct seq_file *f, off_t offset) |
133 | { |
134 | - struct blk_major_name *n; |
135 | - int i, count; |
136 | - |
137 | - count = 0; |
138 | + struct blk_major_name *dp; |
139 | |
140 | - for (i = 0; i < ARRAY_SIZE(major_names); i++) { |
141 | - for (n = major_names[i]; n; n = n->next) |
142 | - count++; |
143 | + if (offset < BLKDEV_MAJOR_HASH_SIZE) { |
144 | + down(&block_subsys_sem); |
145 | + for (dp = major_names[offset]; dp; dp = dp->next) |
146 | + seq_printf(f, "%3d %s\n", dp->major, dp->name); |
147 | + up(&block_subsys_sem); |
148 | } |
149 | - |
150 | - return count; |
151 | -} |
152 | - |
153 | -/* |
154 | - * extract the major and name values from a blkdev_info struct |
155 | - * passed in as a void to *dev. Must be called with |
156 | - * block_subsys_sem held |
157 | - */ |
158 | -int get_blkdev_info(void *dev, int *major, char **name) |
159 | -{ |
160 | - struct blkdev_info *info = dev; |
161 | - |
162 | - if (info->bd == NULL) |
163 | - return 1; |
164 | - |
165 | - *major = info->bd->major; |
166 | - *name = info->bd->name; |
167 | - return 0; |
168 | } |
169 | |
170 | +#endif /* CONFIG_PROC_FS */ |
171 | |
172 | int register_blkdev(unsigned int major, const char *name) |
173 | { |
174 | --- a/fs/char_dev.c |
175 | +++ b/fs/char_dev.c |
176 | @@ -15,6 +15,7 @@ |
177 | #include <linux/module.h> |
178 | #include <linux/smp_lock.h> |
179 | #include <linux/devfs_fs_kernel.h> |
180 | +#include <linux/seq_file.h> |
181 | |
182 | #include <linux/kobject.h> |
183 | #include <linux/kobj_map.h> |
184 | @@ -26,8 +27,6 @@ |
185 | |
186 | static struct kobj_map *cdev_map; |
187 | |
188 | -#define MAX_PROBE_HASH 255 /* random */ |
189 | - |
190 | static DECLARE_MUTEX(chrdevs_lock); |
191 | |
192 | static struct char_device_struct { |
193 | @@ -38,93 +37,29 @@ static struct char_device_struct { |
194 | char name[64]; |
195 | struct file_operations *fops; |
196 | struct cdev *cdev; /* will die */ |
197 | -} *chrdevs[MAX_PROBE_HASH]; |
198 | +} *chrdevs[CHRDEV_MAJOR_HASH_SIZE]; |
199 | |
200 | /* index in the above */ |
201 | static inline int major_to_index(int major) |
202 | { |
203 | - return major % MAX_PROBE_HASH; |
204 | -} |
205 | - |
206 | -struct chrdev_info { |
207 | - int index; |
208 | - struct char_device_struct *cd; |
209 | -}; |
210 | - |
211 | -void *get_next_chrdev(void *dev) |
212 | -{ |
213 | - struct chrdev_info *info; |
214 | - |
215 | - if (dev == NULL) { |
216 | - info = kmalloc(sizeof(*info), GFP_KERNEL); |
217 | - if (!info) |
218 | - goto out; |
219 | - info->index=0; |
220 | - info->cd = chrdevs[info->index]; |
221 | - if (info->cd) |
222 | - goto out; |
223 | - } else { |
224 | - info = dev; |
225 | - } |
226 | - |
227 | - while (info->index < ARRAY_SIZE(chrdevs)) { |
228 | - if (info->cd) |
229 | - info->cd = info->cd->next; |
230 | - if (info->cd) |
231 | - goto out; |
232 | - /* |
233 | - * No devices on this chain, move to the next |
234 | - */ |
235 | - info->index++; |
236 | - info->cd = (info->index < ARRAY_SIZE(chrdevs)) ? |
237 | - chrdevs[info->index] : NULL; |
238 | - if (info->cd) |
239 | - goto out; |
240 | - } |
241 | - |
242 | -out: |
243 | - return info; |
244 | -} |
245 | - |
246 | -void *acquire_chrdev_list(void) |
247 | -{ |
248 | - down(&chrdevs_lock); |
249 | - return get_next_chrdev(NULL); |
250 | -} |
251 | - |
252 | -void release_chrdev_list(void *dev) |
253 | -{ |
254 | - up(&chrdevs_lock); |
255 | - kfree(dev); |
256 | + return major % CHRDEV_MAJOR_HASH_SIZE; |
257 | } |
258 | |
259 | +#ifdef CONFIG_PROC_FS |
260 | |
261 | -int count_chrdev_list(void) |
262 | +void chrdev_show(struct seq_file *f, off_t offset) |
263 | { |
264 | struct char_device_struct *cd; |
265 | - int i, count; |
266 | - |
267 | - count = 0; |
268 | |
269 | - for (i = 0; i < ARRAY_SIZE(chrdevs) ; i++) { |
270 | - for (cd = chrdevs[i]; cd; cd = cd->next) |
271 | - count++; |
272 | + if (offset < CHRDEV_MAJOR_HASH_SIZE) { |
273 | + down(&chrdevs_lock); |
274 | + for (cd = chrdevs[offset]; cd; cd = cd->next) |
275 | + seq_printf(f, "%3d %s\n", cd->major, cd->name); |
276 | + up(&chrdevs_lock); |
277 | } |
278 | - |
279 | - return count; |
280 | } |
281 | |
282 | -int get_chrdev_info(void *dev, int *major, char **name) |
283 | -{ |
284 | - struct chrdev_info *info = dev; |
285 | - |
286 | - if (info->cd == NULL) |
287 | - return 1; |
288 | - |
289 | - *major = info->cd->major; |
290 | - *name = info->cd->name; |
291 | - return 0; |
292 | -} |
293 | +#endif /* CONFIG_PROC_FS */ |
294 | |
295 | /* |
296 | * Register a single major with a specified minor range. |
297 | --- a/fs/proc/proc_misc.c |
298 | +++ b/fs/proc/proc_misc.c |
299 | @@ -249,144 +249,60 @@ static int cpuinfo_open(struct inode *in |
300 | return seq_open(file, &cpuinfo_op); |
301 | } |
302 | |
303 | -enum devinfo_states { |
304 | - CHR_HDR, |
305 | - CHR_LIST, |
306 | - BLK_HDR, |
307 | - BLK_LIST, |
308 | - DEVINFO_DONE |
309 | -}; |
310 | - |
311 | -struct devinfo_state { |
312 | - void *chrdev; |
313 | - void *blkdev; |
314 | - unsigned int num_records; |
315 | - unsigned int cur_record; |
316 | - enum devinfo_states state; |
317 | +static struct file_operations proc_cpuinfo_operations = { |
318 | + .open = cpuinfo_open, |
319 | + .read = seq_read, |
320 | + .llseek = seq_lseek, |
321 | + .release = seq_release, |
322 | }; |
323 | |
324 | -static void *devinfo_start(struct seq_file *f, loff_t *pos) |
325 | +static int devinfo_show(struct seq_file *f, void *v) |
326 | { |
327 | - struct devinfo_state *info = f->private; |
328 | + int i = *(loff_t *) v; |
329 | |
330 | - if (*pos) { |
331 | - if ((info) && (*pos <= info->num_records)) |
332 | - return info; |
333 | - return NULL; |
334 | + if (i < CHRDEV_MAJOR_HASH_SIZE) { |
335 | + if (i == 0) |
336 | + seq_printf(f, "Character devices:\n"); |
337 | + chrdev_show(f, i); |
338 | + } else { |
339 | + i -= CHRDEV_MAJOR_HASH_SIZE; |
340 | + if (i == 0) |
341 | + seq_printf(f, "\nBlock devices:\n"); |
342 | + blkdev_show(f, i); |
343 | } |
344 | - info = kmalloc(sizeof(*info), GFP_KERNEL); |
345 | - f->private = info; |
346 | - info->chrdev = acquire_chrdev_list(); |
347 | - info->blkdev = acquire_blkdev_list(); |
348 | - info->state = CHR_HDR; |
349 | - info->num_records = count_chrdev_list(); |
350 | - info->num_records += count_blkdev_list(); |
351 | - info->num_records += 2; /* Character and Block headers */ |
352 | - *pos = 1; |
353 | - info->cur_record = *pos; |
354 | - return info; |
355 | + return 0; |
356 | } |
357 | |
358 | -static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos) |
359 | +static void *devinfo_start(struct seq_file *f, loff_t *pos) |
360 | { |
361 | - int idummy; |
362 | - char *ndummy; |
363 | - struct devinfo_state *info = f->private; |
364 | - |
365 | - switch (info->state) { |
366 | - case CHR_HDR: |
367 | - info->state = CHR_LIST; |
368 | - (*pos)++; |
369 | - /*fallthrough*/ |
370 | - case CHR_LIST: |
371 | - if (get_chrdev_info(info->chrdev,&idummy,&ndummy)) { |
372 | - /* |
373 | - * The character dev list is complete |
374 | - */ |
375 | - info->state = BLK_HDR; |
376 | - } else { |
377 | - info->chrdev = get_next_chrdev(info->chrdev); |
378 | - } |
379 | - (*pos)++; |
380 | - break; |
381 | - case BLK_HDR: |
382 | - info->state = BLK_LIST; |
383 | - (*pos)++; |
384 | - /*fallthrough*/ |
385 | - case BLK_LIST: |
386 | - if (get_blkdev_info(info->blkdev,&idummy,&ndummy)) { |
387 | - /* |
388 | - * The block dev list is complete |
389 | - */ |
390 | - info->state = DEVINFO_DONE; |
391 | - } else { |
392 | - info->blkdev = get_next_blkdev(info->blkdev); |
393 | - } |
394 | - (*pos)++; |
395 | - break; |
396 | - case DEVINFO_DONE: |
397 | - (*pos)++; |
398 | - info->cur_record = *pos; |
399 | - info = NULL; |
400 | - break; |
401 | - default: |
402 | - break; |
403 | - } |
404 | - if (info) |
405 | - info->cur_record = *pos; |
406 | - return info; |
407 | + if (*pos < (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE)) |
408 | + return pos; |
409 | + return NULL; |
410 | } |
411 | |
412 | -static void devinfo_stop(struct seq_file *f, void *v) |
413 | +static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos) |
414 | { |
415 | - struct devinfo_state *info = f->private; |
416 | - |
417 | - if (info) { |
418 | - release_chrdev_list(info->chrdev); |
419 | - release_blkdev_list(info->blkdev); |
420 | - f->private = NULL; |
421 | - kfree(info); |
422 | - } |
423 | + (*pos)++; |
424 | + if (*pos >= (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE)) |
425 | + return NULL; |
426 | + return pos; |
427 | } |
428 | |
429 | -static int devinfo_show(struct seq_file *f, void *arg) |
430 | +static void devinfo_stop(struct seq_file *f, void *v) |
431 | { |
432 | - int major; |
433 | - char *name; |
434 | - struct devinfo_state *info = f->private; |
435 | - |
436 | - switch(info->state) { |
437 | - case CHR_HDR: |
438 | - seq_printf(f,"Character devices:\n"); |
439 | - /* fallthrough */ |
440 | - case CHR_LIST: |
441 | - if (!get_chrdev_info(info->chrdev,&major,&name)) |
442 | - seq_printf(f,"%3d %s\n",major,name); |
443 | - break; |
444 | - case BLK_HDR: |
445 | - seq_printf(f,"\nBlock devices:\n"); |
446 | - /* fallthrough */ |
447 | - case BLK_LIST: |
448 | - if (!get_blkdev_info(info->blkdev,&major,&name)) |
449 | - seq_printf(f,"%3d %s\n",major,name); |
450 | - break; |
451 | - default: |
452 | - break; |
453 | - } |
454 | - |
455 | - return 0; |
456 | + /* Nothing to do */ |
457 | } |
458 | |
459 | -static struct seq_operations devinfo_op = { |
460 | - .start = devinfo_start, |
461 | - .next = devinfo_next, |
462 | - .stop = devinfo_stop, |
463 | - .show = devinfo_show, |
464 | +static struct seq_operations devinfo_ops = { |
465 | + .start = devinfo_start, |
466 | + .next = devinfo_next, |
467 | + .stop = devinfo_stop, |
468 | + .show = devinfo_show |
469 | }; |
470 | |
471 | -static int devinfo_open(struct inode *inode, struct file *file) |
472 | +static int devinfo_open(struct inode *inode, struct file *filp) |
473 | { |
474 | - return seq_open(file, &devinfo_op); |
475 | + return seq_open(filp, &devinfo_ops); |
476 | } |
477 | |
478 | static struct file_operations proc_devinfo_operations = { |
479 | @@ -396,13 +312,6 @@ static struct file_operations proc_devin |
480 | .release = seq_release, |
481 | }; |
482 | |
483 | -static struct file_operations proc_cpuinfo_operations = { |
484 | - .open = cpuinfo_open, |
485 | - .read = seq_read, |
486 | - .llseek = seq_lseek, |
487 | - .release = seq_release, |
488 | -}; |
489 | - |
490 | extern struct seq_operations vmstat_op; |
491 | static int vmstat_open(struct inode *inode, struct file *file) |
492 | { |
493 | --- a/include/linux/fs.h |
494 | +++ b/include/linux/fs.h |
495 | @@ -1383,6 +1383,7 @@ extern int bd_claim(struct block_device |
496 | extern void bd_release(struct block_device *); |
497 | |
498 | /* fs/char_dev.c */ |
499 | +#define CHRDEV_MAJOR_HASH_SIZE 255 |
500 | extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *); |
501 | extern int register_chrdev_region(dev_t, unsigned, const char *); |
502 | extern int register_chrdev(unsigned int, const char *, |
503 | @@ -1390,25 +1391,17 @@ extern int register_chrdev(unsigned int, |
504 | extern int unregister_chrdev(unsigned int, const char *); |
505 | extern void unregister_chrdev_region(dev_t, unsigned); |
506 | extern int chrdev_open(struct inode *, struct file *); |
507 | -extern int get_chrdev_list(char *); |
508 | -extern void *acquire_chrdev_list(void); |
509 | -extern int count_chrdev_list(void); |
510 | -extern void *get_next_chrdev(void *); |
511 | -extern int get_chrdev_info(void *, int *, char **); |
512 | -extern void release_chrdev_list(void *); |
513 | +extern void chrdev_show(struct seq_file *,off_t); |
514 | |
515 | /* fs/block_dev.c */ |
516 | +#define BLKDEV_MAJOR_HASH_SIZE 255 |
517 | #define BDEVNAME_SIZE 32 /* Largest string for a blockdev identifier */ |
518 | extern const char *__bdevname(dev_t, char *buffer); |
519 | extern const char *bdevname(struct block_device *bdev, char *buffer); |
520 | extern struct block_device *lookup_bdev(const char *); |
521 | extern struct block_device *open_bdev_excl(const char *, int, void *); |
522 | extern void close_bdev_excl(struct block_device *); |
523 | -extern void *acquire_blkdev_list(void); |
524 | -extern int count_blkdev_list(void); |
525 | -extern void *get_next_blkdev(void *); |
526 | -extern int get_blkdev_info(void *, int *, char **); |
527 | -extern void release_blkdev_list(void *); |
528 | +extern void blkdev_show(struct seq_file *,off_t); |
529 | |
530 | extern void init_special_inode(struct inode *, umode_t, dev_t); |
531 |