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mtd: Replace static array of devices with an idr structure
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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>
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Ben Hutchings authored and David Woodhouse committed Feb 25, 2010
1 parent 4d1ee80 commit b520e41
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Showing 3 changed files with 81 additions and 83 deletions.
151 changes: 80 additions & 71 deletions drivers/mtd/mtdcore.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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"
Expand All @@ -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);

Expand Down Expand Up @@ -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) {
Expand All @@ -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;
}
Expand All @@ -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",
Expand All @@ -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;
Expand Down Expand Up @@ -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;
}
Expand Down
12 changes: 1 addition & 11 deletions drivers/mtd/mtdcore.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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); \
Expand Down
1 change: 0 additions & 1 deletion include/linux/mtd/mtd.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down

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