sysmo-bts
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barebox
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devfs: add open counter 

Add an open counter for device files so that we cannot accidently
remove an opened device. This happened with bb devices.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Sascha Hauer 2009-09-10 12:07:10 +02:00
parent 2ee3e596c5
commit f46010a1ab
2 changed files with 31 additions and 8 deletions
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36
fs/devfs.c
View File

@ -130,6 +130,7 @@ static int devfs_memmap(struct device_d *_dev, FILE *f, void **map, int flags)
static int devfs_open(struct device_d *_dev, FILE *f, const char *filename)
{
struct cdev *cdev;
int ret;
cdev = cdev_by_name(filename + 1);
@ -139,8 +140,13 @@ static int devfs_open(struct device_d *_dev, FILE *f, const char *filename)
f->size = cdev->size;
f->inode = cdev;
if (cdev->ops->open)
return cdev->ops->open(cdev, f);
if (cdev->ops->open) {
ret = cdev->ops->open(cdev, f);
if (ret)
return ret;
}
cdev->open++;
return 0;
}
@ -148,9 +154,16 @@ static int devfs_open(struct device_d *_dev, FILE *f, const char *filename)
static int devfs_close(struct device_d *_dev, FILE *f)
{
struct cdev *cdev = f->inode;
int ret;
if (cdev->ops->close) {
ret = cdev->ops->close(cdev, f);
if (ret)
return ret;
}
cdev->open--;
if (cdev->ops->close)
return cdev->ops->close(cdev, f);
return 0;
}
@ -301,11 +314,16 @@ int devfs_create(struct cdev *new)
return 0;
}
void devfs_remove(struct cdev *cdev)
int devfs_remove(struct cdev *cdev)
{
if (cdev->open)
return -EBUSY;
list_del(&cdev->list);
if (cdev->dev)
list_del(&cdev->devices_list);
return 0;
}
int devfs_add_partition(const char *devname, unsigned long offset, size_t size,
@ -333,7 +351,7 @@ int devfs_add_partition(const char *devname, unsigned long offset, size_t size,
new->dev = cdev->dev;
new->flags = flags | DEVFS_IS_PARTITION;
list_add_tail(&new->list, &cdev_list);
devfs_create(new);
return 0;
}
@ -341,6 +359,7 @@ int devfs_add_partition(const char *devname, unsigned long offset, size_t size,
int devfs_del_partition(const char *name)
{
struct cdev *cdev;
int ret;
cdev = cdev_by_name(name);
if (!cdev)
@ -351,7 +370,10 @@ int devfs_del_partition(const char *name)
if (cdev->flags & DEVFS_PARTITION_FIXED)
return -EPERM;
devfs_remove(cdev);
ret = devfs_remove(cdev);
if (ret)
return ret;
free(cdev->name);
free(cdev);

3
include/driver.h
View File

@ -301,10 +301,11 @@ struct cdev {
unsigned long offset;
size_t size;
unsigned int flags;
int open;
};
int devfs_create(struct cdev *);
void devfs_remove(struct cdev *);
int devfs_remove(struct cdev *);
struct cdev *cdev_by_name(const char *filename);
ssize_t cdev_read(struct cdev *cdev, void *buf, size_t count, ulong offset, ulong flags);
ssize_t cdev_write(struct cdev *cdev, const void *buf, size_t count, ulong offset, ulong flags);