Commit e84f9e57 authored by Al Viro's avatar Al Viro

consolidate the reassignments of ->f_op in ->open() instances

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 7b00ed6f
...@@ -114,7 +114,7 @@ static int misc_open(struct inode * inode, struct file * file) ...@@ -114,7 +114,7 @@ static int misc_open(struct inode * inode, struct file * file)
int minor = iminor(inode); int minor = iminor(inode);
struct miscdevice *c; struct miscdevice *c;
int err = -ENODEV; int err = -ENODEV;
const struct file_operations *old_fops, *new_fops = NULL; const struct file_operations *new_fops = NULL;
mutex_lock(&misc_mtx); mutex_lock(&misc_mtx);
...@@ -141,17 +141,11 @@ static int misc_open(struct inode * inode, struct file * file) ...@@ -141,17 +141,11 @@ static int misc_open(struct inode * inode, struct file * file)
} }
err = 0; err = 0;
old_fops = file->f_op; replace_fops(file, new_fops);
file->f_op = new_fops;
if (file->f_op->open) { if (file->f_op->open) {
file->private_data = c; file->private_data = c;
err=file->f_op->open(inode,file); err = file->f_op->open(inode,file);
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
} }
fops_put(old_fops);
fail: fail:
mutex_unlock(&misc_mtx); mutex_unlock(&misc_mtx);
return err; return err;
......
...@@ -148,7 +148,7 @@ int drm_stub_open(struct inode *inode, struct file *filp) ...@@ -148,7 +148,7 @@ int drm_stub_open(struct inode *inode, struct file *filp)
struct drm_minor *minor; struct drm_minor *minor;
int minor_id = iminor(inode); int minor_id = iminor(inode);
int err = -ENODEV; int err = -ENODEV;
const struct file_operations *old_fops; const struct file_operations *new_fops;
DRM_DEBUG("\n"); DRM_DEBUG("\n");
...@@ -163,18 +163,13 @@ int drm_stub_open(struct inode *inode, struct file *filp) ...@@ -163,18 +163,13 @@ int drm_stub_open(struct inode *inode, struct file *filp)
if (drm_device_is_unplugged(dev)) if (drm_device_is_unplugged(dev))
goto out; goto out;
old_fops = filp->f_op; new_fops = fops_get(dev->driver->fops);
filp->f_op = fops_get(dev->driver->fops); if (!new_fops)
if (filp->f_op == NULL) {
filp->f_op = old_fops;
goto out; goto out;
}
if (filp->f_op->open && (err = filp->f_op->open(inode, filp))) {
fops_put(filp->f_op);
filp->f_op = fops_get(old_fops);
}
fops_put(old_fops);
replace_fops(filp, new_fops);
if (filp->f_op->open)
err = filp->f_op->open(inode, filp);
out: out:
mutex_unlock(&drm_global_mutex); mutex_unlock(&drm_global_mutex);
return err; return err;
......
...@@ -74,22 +74,15 @@ static int dvb_device_open(struct inode *inode, struct file *file) ...@@ -74,22 +74,15 @@ static int dvb_device_open(struct inode *inode, struct file *file)
if (dvbdev && dvbdev->fops) { if (dvbdev && dvbdev->fops) {
int err = 0; int err = 0;
const struct file_operations *old_fops; const struct file_operations *new_fops;
file->private_data = dvbdev; new_fops = fops_get(dvbdev->fops);
old_fops = file->f_op; if (!new_fops)
file->f_op = fops_get(dvbdev->fops);
if (file->f_op == NULL) {
file->f_op = old_fops;
goto fail; goto fail;
} file->private_data = dvbdev;
if(file->f_op->open) replace_fops(file, new_fops);
if (file->f_op->open)
err = file->f_op->open(inode,file); err = file->f_op->open(inode,file);
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
fops_put(old_fops);
up_read(&minor_rwsem); up_read(&minor_rwsem);
mutex_unlock(&dvbdev_mutex); mutex_unlock(&dvbdev_mutex);
return err; return err;
......
...@@ -29,27 +29,19 @@ static DECLARE_RWSEM(minor_rwsem); ...@@ -29,27 +29,19 @@ static DECLARE_RWSEM(minor_rwsem);
static int usb_open(struct inode * inode, struct file * file) static int usb_open(struct inode * inode, struct file * file)
{ {
int minor = iminor(inode);
const struct file_operations *c;
int err = -ENODEV; int err = -ENODEV;
const struct file_operations *old_fops, *new_fops = NULL; const struct file_operations *new_fops;
down_read(&minor_rwsem); down_read(&minor_rwsem);
c = usb_minors[minor]; new_fops = fops_get(usb_minors[iminor(inode)]);
if (!c || !(new_fops = fops_get(c))) if (!new_fops)
goto done; goto done;
old_fops = file->f_op; replace_fops(file, new_fops);
file->f_op = new_fops;
/* Curiouser and curiouser... NULL ->open() as "no device" ? */ /* Curiouser and curiouser... NULL ->open() as "no device" ? */
if (file->f_op->open) if (file->f_op->open)
err = file->f_op->open(inode,file); err = file->f_op->open(inode,file);
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
fops_put(old_fops);
done: done:
up_read(&minor_rwsem); up_read(&minor_rwsem);
return err; return err;
......
...@@ -368,6 +368,7 @@ void cdev_put(struct cdev *p) ...@@ -368,6 +368,7 @@ void cdev_put(struct cdev *p)
*/ */
static int chrdev_open(struct inode *inode, struct file *filp) static int chrdev_open(struct inode *inode, struct file *filp)
{ {
const struct file_operations *fops;
struct cdev *p; struct cdev *p;
struct cdev *new = NULL; struct cdev *new = NULL;
int ret = 0; int ret = 0;
...@@ -400,10 +401,11 @@ static int chrdev_open(struct inode *inode, struct file *filp) ...@@ -400,10 +401,11 @@ static int chrdev_open(struct inode *inode, struct file *filp)
return ret; return ret;
ret = -ENXIO; ret = -ENXIO;
filp->f_op = fops_get(p->ops); fops = fops_get(p->ops);
if (!filp->f_op) if (!fops)
goto out_cdev_put; goto out_cdev_put;
replace_fops(filp, fops);
if (filp->f_op->open) { if (filp->f_op->open) {
ret = filp->f_op->open(inode, filp); ret = filp->f_op->open(inode, filp);
if (ret) if (ret)
......
...@@ -1875,6 +1875,17 @@ extern struct dentry *mount_pseudo(struct file_system_type *, char *, ...@@ -1875,6 +1875,17 @@ extern struct dentry *mount_pseudo(struct file_system_type *, char *,
(((fops) && try_module_get((fops)->owner) ? (fops) : NULL)) (((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
#define fops_put(fops) \ #define fops_put(fops) \
do { if (fops) module_put((fops)->owner); } while(0) do { if (fops) module_put((fops)->owner); } while(0)
/*
* This one is to be used *ONLY* from ->open() instances.
* fops must be non-NULL, pinned down *and* module dependencies
* should be sufficient to pin the caller down as well.
*/
#define replace_fops(f, fops) \
do { \
struct file *__file = (f); \
fops_put(__file->f_op); \
BUG_ON(!(__file->f_op = (fops))); \
} while(0)
extern int register_filesystem(struct file_system_type *); extern int register_filesystem(struct file_system_type *);
extern int unregister_filesystem(struct file_system_type *); extern int unregister_filesystem(struct file_system_type *);
......
...@@ -153,7 +153,7 @@ static int snd_open(struct inode *inode, struct file *file) ...@@ -153,7 +153,7 @@ static int snd_open(struct inode *inode, struct file *file)
{ {
unsigned int minor = iminor(inode); unsigned int minor = iminor(inode);
struct snd_minor *mptr = NULL; struct snd_minor *mptr = NULL;
const struct file_operations *old_fops; const struct file_operations *new_fops;
int err = 0; int err = 0;
if (minor >= ARRAY_SIZE(snd_minors)) if (minor >= ARRAY_SIZE(snd_minors))
...@@ -167,24 +167,14 @@ static int snd_open(struct inode *inode, struct file *file) ...@@ -167,24 +167,14 @@ static int snd_open(struct inode *inode, struct file *file)
return -ENODEV; return -ENODEV;
} }
} }
old_fops = file->f_op; new_fops = fops_get(mptr->f_ops);
file->f_op = fops_get(mptr->f_ops);
if (file->f_op == NULL) {
file->f_op = old_fops;
err = -ENODEV;
}
mutex_unlock(&sound_mutex); mutex_unlock(&sound_mutex);
if (err < 0) if (!new_fops)
return err; return -ENODEV;
replace_fops(file, new_fops);
if (file->f_op->open) { if (file->f_op->open)
err = file->f_op->open(inode, file); err = file->f_op->open(inode, file);
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
}
fops_put(old_fops);
return err; return err;
} }
......
...@@ -626,31 +626,20 @@ static int soundcore_open(struct inode *inode, struct file *file) ...@@ -626,31 +626,20 @@ static int soundcore_open(struct inode *inode, struct file *file)
if (s) if (s)
new_fops = fops_get(s->unit_fops); new_fops = fops_get(s->unit_fops);
} }
spin_unlock(&sound_loader_lock);
if (new_fops) { if (new_fops) {
/* /*
* We rely upon the fact that we can't be unloaded while the * We rely upon the fact that we can't be unloaded while the
* subdriver is there, so if ->open() is successful we can * subdriver is there.
* safely drop the reference counter and if it is not we can
* revert to old ->f_op. Ugly, indeed, but that's the cost of
* switching ->f_op in the first place.
*/ */
int err = 0; int err = 0;
const struct file_operations *old_fops = file->f_op; replace_fops(file, new_fops);
file->f_op = new_fops;
spin_unlock(&sound_loader_lock);
if (file->f_op->open) if (file->f_op->open)
err = file->f_op->open(inode,file); err = file->f_op->open(inode,file);
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
fops_put(old_fops);
return err; return err;
} }
spin_unlock(&sound_loader_lock);
return -ENODEV; return -ENODEV;
} }
......
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