[PATCHv2 6/7] mtd: Replace static array of devices with an idr structure
Ben Hutchings
bhutchings at solarflare.com
Tue Jan 12 18:09:44 EST 2010
Signed-off-by: Ben Hutchings <bhutchings at solarflare.com>
---
drivers/mtd/mtdcore.c | 151 +++++++++++++++++++++++++----------------------
drivers/mtd/mtdcore.h | 12 +----
include/linux/mtd/mtd.h | 1 -
3 files changed, 81 insertions(+), 83 deletions(-)
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 402d417..b3b98d1 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -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"
@@ -33,13 +34,18 @@ static struct class mtd_class = {
.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 @@ static struct device_type mtd_devtype = {
* 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) {
@@ -260,70 +266,73 @@ int add_mtd_device(struct mtd_info *mtd)
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;
-
- mtd_table[i] = mtd;
- mtd->index = i;
- mtd->usecount = 0;
-
- if (is_power_of_2(mtd->erasesize))
- mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
- else
- mtd->erasesize_shift = 0;
-
- if (is_power_of_2(mtd->writesize))
- mtd->writesize_shift = ffs(mtd->writesize) - 1;
- else
- mtd->writesize_shift = 0;
-
- mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
- mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
-
- /* 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);
- }
+ do {
+ if (!idr_pre_get(&mtd_idr, GFP_KERNEL))
+ goto fail_locked;
+ error = idr_get_new(&mtd_idr, mtd, &i);
+ } while (error == -EAGAIN);
- /* 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;
- }
+ if (error)
+ goto fail_locked;
- if (MTD_DEVT(i))
- device_create(&mtd_class, mtd->dev.parent,
- MTD_DEVT(i) + 1,
- NULL, "mtd%dro", i);
-
- 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;
- }
+ mtd->index = i;
+ mtd->usecount = 0;
+
+ if (is_power_of_2(mtd->erasesize))
+ mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
+ else
+ mtd->erasesize_shift = 0;
+
+ if (is_power_of_2(mtd->writesize))
+ mtd->writesize_shift = ffs(mtd->writesize) - 1;
+ else
+ mtd->writesize_shift = 0;
+
+ mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
+ mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
+
+ /* 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);
+ }
+
+ /* 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;
+
+ if (MTD_DEVT(i))
+ device_create(&mtd_class, mtd->dev.parent,
+ MTD_DEVT(i) + 1,
+ NULL, "mtd%dro", i);
+
+ 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 @@ int del_mtd_device (struct mtd_info *mtd)
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 @@ int del_mtd_device (struct mtd_info *mtd)
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 @@ struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
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;
}
diff --git a/drivers/mtd/mtdcore.h b/drivers/mtd/mtdcore.h
index e2f93a3..6a64fde 100644
--- a/drivers/mtd/mtdcore.h
+++ b/drivers/mtd/mtdcore.h
@@ -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); \
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 0f32a9b..ba53ecc 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -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
--
1.5.5
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
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