mtd: Replace static array of devices with an idr structure

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

mtd: Replace static array of devices with an idr structure
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Ben Hutchings · David Woodhouse
1 parent 4d1ee80f3a
Showing 3 changed files with 81 additions and 83 deletions Side-by-side Diff
drivers/mtd/mtdcore.c
drivers/mtd/mtdcore.h
include/linux/mtd/mtd.h
@@ -17,6 +17,7 @@
 #include <linux/init.h>
 #include <linux/mtd/compatmac.h>
 #include <linux/proc_fs.h>
+#include <linux/idr.h>
  
 #include <linux/mtd/mtd.h>
 #include "internal.h"
  
  
  
@@ -33,14 +34,19 @@
 	.resume = mtd_cls_resume,
 };
  
+static DEFINE_IDR(mtd_idr);
+
 /* These are exported solely for the purpose of mtd_blkdevs.c. You
    should not use them for _anything_ else */
 DEFINE_MUTEX(mtd_table_mutex);
-struct mtd_info *mtd_table[MAX_MTD_DEVICES];
-
 EXPORT_SYMBOL_GPL(mtd_table_mutex);
-EXPORT_SYMBOL_GPL(mtd_table);
  
+struct mtd_info *__mtd_next_device(int i)
+{
+	return idr_get_next(&mtd_idr, &i);
+}
+EXPORT_SYMBOL_GPL(__mtd_next_device);
+
 static LIST_HEAD(mtd_notifiers);
  
  
  
@@ -235,13 +241,13 @@
  *	Add a device to the list of MTD devices present in the system, and
  *	notify each currently active MTD 'user' of its arrival. Returns
  *	zero on success or 1 on failure, which currently will only happen
- *	if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16)
- *	or there's a sysfs error.
+ *	if there is insufficient memory or a sysfs error.
  */
  
 int add_mtd_device(struct mtd_info *mtd)
 {
-	int i;
+	struct mtd_notifier *not;
+	int i, error;
  
 	if (!mtd->backing_dev_info) {
 		switch (mtd->type) {
  
  
  
  
  
  
  
  
  
  
@@ -260,71 +266,74 @@
 	BUG_ON(mtd->writesize == 0);
 	mutex_lock(&mtd_table_mutex);
  
-	for (i=0; i < MAX_MTD_DEVICES; i++)
-		if (!mtd_table[i]) {
-			struct mtd_notifier *not;
+	do {
+		if (!idr_pre_get(&mtd_idr, GFP_KERNEL))
+			goto fail_locked;
+		error = idr_get_new(&mtd_idr, mtd, &i);
+	} while (error == -EAGAIN);
  
-			mtd_table[i] = mtd;
-			mtd->index = i;
-			mtd->usecount = 0;
+	if (error)
+		goto fail_locked;
  
-			if (is_power_of_2(mtd->erasesize))
-				mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
-			else
-				mtd->erasesize_shift = 0;
+	mtd->index = i;
+	mtd->usecount = 0;
  
-			if (is_power_of_2(mtd->writesize))
-				mtd->writesize_shift = ffs(mtd->writesize) - 1;
-			else
-				mtd->writesize_shift = 0;
+	if (is_power_of_2(mtd->erasesize))
+		mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
+	else
+		mtd->erasesize_shift = 0;
  
-			mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
-			mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
+	if (is_power_of_2(mtd->writesize))
+		mtd->writesize_shift = ffs(mtd->writesize) - 1;
+	else
+		mtd->writesize_shift = 0;
  
-			/* Some chips always power up locked. Unlock them now */
-			if ((mtd->flags & MTD_WRITEABLE)
-			    && (mtd->flags & MTD_POWERUP_LOCK) && mtd->unlock) {
-				if (mtd->unlock(mtd, 0, mtd->size))
-					printk(KERN_WARNING
-					       "%s: unlock failed, "
-					       "writes may not work\n",
-					       mtd->name);
-			}
+	mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
+	mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
  
-			/* Caller should have set dev.parent to match the
-			 * physical device.
-			 */
-			mtd->dev.type = &mtd_devtype;
-			mtd->dev.class = &mtd_class;
-			mtd->dev.devt = MTD_DEVT(i);
-			dev_set_name(&mtd->dev, "mtd%d", i);
-			dev_set_drvdata(&mtd->dev, mtd);
-			if (device_register(&mtd->dev) != 0) {
-				mtd_table[i] = NULL;
-				break;
-			}
+	/* Some chips always power up locked. Unlock them now */
+	if ((mtd->flags & MTD_WRITEABLE)
+	    && (mtd->flags & MTD_POWERUP_LOCK) && mtd->unlock) {
+		if (mtd->unlock(mtd, 0, mtd->size))
+			printk(KERN_WARNING
+			       "%s: unlock failed, writes may not work\n",
+			       mtd->name);
+	}
  
-			if (MTD_DEVT(i))
-				device_create(&mtd_class, mtd->dev.parent,
-						MTD_DEVT(i) + 1,
-						NULL, "mtd%dro", i);
+	/* Caller should have set dev.parent to match the
+	 * physical device.
+	 */
+	mtd->dev.type = &mtd_devtype;
+	mtd->dev.class = &mtd_class;
+	mtd->dev.devt = MTD_DEVT(i);
+	dev_set_name(&mtd->dev, "mtd%d", i);
+	dev_set_drvdata(&mtd->dev, mtd);
+	if (device_register(&mtd->dev) != 0)
+		goto fail_added;
  
-			DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
-			/* No need to get a refcount on the module containing
-			   the notifier, since we hold the mtd_table_mutex */
-			list_for_each_entry(not, &mtd_notifiers, list)
-				not->add(mtd);
+	if (MTD_DEVT(i))
+		device_create(&mtd_class, mtd->dev.parent,
+			      MTD_DEVT(i) + 1,
+			      NULL, "mtd%dro", i);
  
-			mutex_unlock(&mtd_table_mutex);
-			/* We _know_ we aren't being removed, because
-			   our caller is still holding us here. So none
-			   of this try_ nonsense, and no bitching about it
-			   either. :) */
-			__module_get(THIS_MODULE);
-			return 0;
-		}
+	DEBUG(0, "mtd: Giving out device %d to %s\n", i, mtd->name);
+	/* No need to get a refcount on the module containing
+	   the notifier, since we hold the mtd_table_mutex */
+	list_for_each_entry(not, &mtd_notifiers, list)
+		not->add(mtd);
  
 	mutex_unlock(&mtd_table_mutex);
+	/* We _know_ we aren't being removed, because
+	   our caller is still holding us here. So none
+	   of this try_ nonsense, and no bitching about it
+	   either. :) */
+	__module_get(THIS_MODULE);
+	return 0;
+
+fail_added:
+	idr_remove(&mtd_idr, i);
+fail_locked:
+	mutex_unlock(&mtd_table_mutex);
 	return 1;
 }
  
@@ -344,7 +353,7 @@
  
 	mutex_lock(&mtd_table_mutex);
  
-	if (mtd_table[mtd->index] != mtd) {
+	if (idr_find(&mtd_idr, mtd->index) != mtd) {
 		ret = -ENODEV;
 	} else if (mtd->usecount) {
 		printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
@@ -360,7 +369,7 @@
 		list_for_each_entry(not, &mtd_notifiers, list)
 			not->remove(mtd);
  
-		mtd_table[mtd->index] = NULL;
+		idr_remove(&mtd_idr, mtd->index);
  
 		module_put(THIS_MODULE);
 		ret = 0;
@@ -448,8 +457,8 @@
 				break;
 			}
 		}
-	} else if (num >= 0 && num < MAX_MTD_DEVICES) {
-		ret = mtd_table[num];
+	} else if (num >= 0) {
+		ret = idr_find(&mtd_idr, num);
 		if (mtd && mtd != ret)
 			ret = NULL;
 	}
@@ -8,17 +8,7 @@
    should not use them for _anything_ else */
  
 extern struct mutex mtd_table_mutex;
-extern struct mtd_info *mtd_table[MAX_MTD_DEVICES];
-
-static inline struct mtd_info *__mtd_next_device(int i)
-{
-	while (i < MAX_MTD_DEVICES) {
-		if (mtd_table[i])
-			return mtd_table[i];
-		i++;
-	}
-	return NULL;
-}
+extern struct mtd_info *__mtd_next_device(int i);
  
 #define mtd_for_each_device(mtd)			\
 	for ((mtd) = __mtd_next_device(0);		\
@@ -20,7 +20,6 @@
  
 #define MTD_CHAR_MAJOR 90
 #define MTD_BLOCK_MAJOR 31
-#define MAX_MTD_DEVICES 32
  
 #define MTD_ERASE_PENDING      	0x01
 #define MTD_ERASING		0x02
...	...	@@ -17,6 +17,7 @@
17	17	#include <linux/init.h>
18	18	#include <linux/mtd/compatmac.h>
19	19	#include <linux/proc_fs.h>
	20	+#include <linux/idr.h>
20	21
21	22	#include <linux/mtd/mtd.h>
22	23	#include "internal.h"
23	24
24	25
25	26
...	...	@@ -33,14 +34,19 @@
33	34	.resume = mtd_cls_resume,
34	35	};
35	36
	37	+static DEFINE_IDR(mtd_idr);
	38	+
36	39	/* These are exported solely for the purpose of mtd_blkdevs.c. You
37	40	should not use them for _anything_ else */
38	41	DEFINE_MUTEX(mtd_table_mutex);
39		-struct mtd_info *mtd_table[MAX_MTD_DEVICES];
40		-
41	42	EXPORT_SYMBOL_GPL(mtd_table_mutex);
42		-EXPORT_SYMBOL_GPL(mtd_table);
43	43
	44	+struct mtd_info *__mtd_next_device(int i)
	45	+{
	46	+ return idr_get_next(&mtd_idr, &i);
	47	+}
	48	+EXPORT_SYMBOL_GPL(__mtd_next_device);
	49	+
44	50	static LIST_HEAD(mtd_notifiers);
45	51
46	52
47	53
...	...	@@ -235,13 +241,13 @@
235	241	* Add a device to the list of MTD devices present in the system, and
236	242	* notify each currently active MTD 'user' of its arrival. Returns
237	243	* zero on success or 1 on failure, which currently will only happen
238		- * if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16)
239		- * or there's a sysfs error.
	244	+ * if there is insufficient memory or a sysfs error.
240	245	*/
241	246
242	247	int add_mtd_device(struct mtd_info *mtd)
243	248	{
244		- int i;
	249	+ struct mtd_notifier *not;
	250	+ int i, error;
245	251
246	252	if (!mtd->backing_dev_info) {
247	253	switch (mtd->type) {
248	254
249	255
250	256
251	257
252	258
253	259
254	260
255	261
256	262
257	263
...	...	@@ -260,71 +266,74 @@
260	266	BUG_ON(mtd->writesize == 0);
261	267	mutex_lock(&mtd_table_mutex);
262	268
263		- for (i=0; i < MAX_MTD_DEVICES; i++)
264		- if (!mtd_table[i]) {
265		- struct mtd_notifier *not;
	269	+ do {
	270	+ if (!idr_pre_get(&mtd_idr, GFP_KERNEL))
	271	+ goto fail_locked;
	272	+ error = idr_get_new(&mtd_idr, mtd, &i);
	273	+ } while (error == -EAGAIN);
266	274
267		- mtd_table[i] = mtd;
268		- mtd->index = i;
269		- mtd->usecount = 0;
	275	+ if (error)
	276	+ goto fail_locked;
270	277
271		- if (is_power_of_2(mtd->erasesize))
272		- mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
273		- else
274		- mtd->erasesize_shift = 0;
	278	+ mtd->index = i;
	279	+ mtd->usecount = 0;
275	280
276		- if (is_power_of_2(mtd->writesize))
277		- mtd->writesize_shift = ffs(mtd->writesize) - 1;
278		- else
279		- mtd->writesize_shift = 0;
	281	+ if (is_power_of_2(mtd->erasesize))
	282	+ mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
	283	+ else
	284	+ mtd->erasesize_shift = 0;
280	285
281		- mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
282		- mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
	286	+ if (is_power_of_2(mtd->writesize))
	287	+ mtd->writesize_shift = ffs(mtd->writesize) - 1;
	288	+ else
	289	+ mtd->writesize_shift = 0;
283	290
284		- /* Some chips always power up locked. Unlock them now */
285		- if ((mtd->flags & MTD_WRITEABLE)
286		- && (mtd->flags & MTD_POWERUP_LOCK) && mtd->unlock) {
287		- if (mtd->unlock(mtd, 0, mtd->size))
288		- printk(KERN_WARNING
289		- "%s: unlock failed, "
290		- "writes may not work\n",
291		- mtd->name);
292		- }
	291	+ mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
	292	+ mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
293	293
294		- /* Caller should have set dev.parent to match the
295		- * physical device.
296		- */
297		- mtd->dev.type = &mtd_devtype;
298		- mtd->dev.class = &mtd_class;
299		- mtd->dev.devt = MTD_DEVT(i);
300		- dev_set_name(&mtd->dev, "mtd%d", i);
301		- dev_set_drvdata(&mtd->dev, mtd);
302		- if (device_register(&mtd->dev) != 0) {
303		- mtd_table[i] = NULL;
304		- break;
305		- }
	294	+ /* Some chips always power up locked. Unlock them now */
	295	+ if ((mtd->flags & MTD_WRITEABLE)
	296	+ && (mtd->flags & MTD_POWERUP_LOCK) && mtd->unlock) {
	297	+ if (mtd->unlock(mtd, 0, mtd->size))
	298	+ printk(KERN_WARNING
	299	+ "%s: unlock failed, writes may not work\n",
	300	+ mtd->name);
	301	+ }
306	302
307		- if (MTD_DEVT(i))
308		- device_create(&mtd_class, mtd->dev.parent,
309		- MTD_DEVT(i) + 1,
310		- NULL, "mtd%dro", i);
	303	+ /* Caller should have set dev.parent to match the
	304	+ * physical device.
	305	+ */
	306	+ mtd->dev.type = &mtd_devtype;
	307	+ mtd->dev.class = &mtd_class;
	308	+ mtd->dev.devt = MTD_DEVT(i);
	309	+ dev_set_name(&mtd->dev, "mtd%d", i);
	310	+ dev_set_drvdata(&mtd->dev, mtd);
	311	+ if (device_register(&mtd->dev) != 0)
	312	+ goto fail_added;
311	313
312		- DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
313		- /* No need to get a refcount on the module containing
314		- the notifier, since we hold the mtd_table_mutex */
315		- list_for_each_entry(not, &mtd_notifiers, list)
316		- not->add(mtd);
	314	+ if (MTD_DEVT(i))
	315	+ device_create(&mtd_class, mtd->dev.parent,
	316	+ MTD_DEVT(i) + 1,
	317	+ NULL, "mtd%dro", i);
317	318
318		- mutex_unlock(&mtd_table_mutex);
319		- /* We _know_ we aren't being removed, because
320		- our caller is still holding us here. So none
321		- of this try_ nonsense, and no bitching about it
322		- either. :) */
323		- __module_get(THIS_MODULE);
324		- return 0;
325		- }
	319	+ DEBUG(0, "mtd: Giving out device %d to %s\n", i, mtd->name);
	320	+ /* No need to get a refcount on the module containing
	321	+ the notifier, since we hold the mtd_table_mutex */
	322	+ list_for_each_entry(not, &mtd_notifiers, list)
	323	+ not->add(mtd);
326	324
327	325	mutex_unlock(&mtd_table_mutex);
	326	+ /* We _know_ we aren't being removed, because
	327	+ our caller is still holding us here. So none
	328	+ of this try_ nonsense, and no bitching about it
	329	+ either. :) */
	330	+ __module_get(THIS_MODULE);
	331	+ return 0;
	332	+
	333	+fail_added:
	334	+ idr_remove(&mtd_idr, i);
	335	+fail_locked:
	336	+ mutex_unlock(&mtd_table_mutex);
328	337	return 1;
329	338	}
330	339
...	...	@@ -344,7 +353,7 @@
344	353
345	354	mutex_lock(&mtd_table_mutex);
346	355
347		- if (mtd_table[mtd->index] != mtd) {
	356	+ if (idr_find(&mtd_idr, mtd->index) != mtd) {
348	357	ret = -ENODEV;
349	358	} else if (mtd->usecount) {
350	359	printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
...	...	@@ -360,7 +369,7 @@
360	369	list_for_each_entry(not, &mtd_notifiers, list)
361	370	not->remove(mtd);
362	371
363		- mtd_table[mtd->index] = NULL;
	372	+ idr_remove(&mtd_idr, mtd->index);
364	373
365	374	module_put(THIS_MODULE);
366	375	ret = 0;
...	...	@@ -448,8 +457,8 @@
448	457	break;
449	458	}
450	459	}
451		- } else if (num >= 0 && num < MAX_MTD_DEVICES) {
452		- ret = mtd_table[num];
	460	+ } else if (num >= 0) {
	461	+ ret = idr_find(&mtd_idr, num);
453	462	if (mtd && mtd != ret)
454	463	ret = NULL;
455	464	}
...	...	@@ -8,17 +8,7 @@
8	8	should not use them for _anything_ else */
9	9
10	10	extern struct mutex mtd_table_mutex;
11		-extern struct mtd_info *mtd_table[MAX_MTD_DEVICES];
12		-
13		-static inline struct mtd_info *__mtd_next_device(int i)
14		-{
15		- while (i < MAX_MTD_DEVICES) {
16		- if (mtd_table[i])
17		- return mtd_table[i];
18		- i++;
19		- }
20		- return NULL;
21		-}
	11	+extern struct mtd_info *__mtd_next_device(int i);
22	12
23	13	#define mtd_for_each_device(mtd) \
24	14	for ((mtd) = __mtd_next_device(0); \
...	...	@@ -20,7 +20,6 @@
20	20
21	21	#define MTD_CHAR_MAJOR 90
22	22	#define MTD_BLOCK_MAJOR 31
23		-#define MAX_MTD_DEVICES 32
24	23
25	24	#define MTD_ERASE_PENDING 0x01
26	25	#define MTD_ERASING 0x02