diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 65894fd8b67b724a0637914b8c22a7e84672251d..79b852c6d868c81dbcf454e0a241ec3fce98f012 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -43,6 +43,22 @@
#include "comedi_internal.h"
+/**
+ * struct comedi_file - per-file private data for comedi device
+ * @dev: comedi_device struct
+ * @read_subdev: current "read" subdevice
+ * @write_subdev: current "write" subdevice
+ * @last_detach_count: last known detach count
+ * @last_attached: last known attached/detached state
+ */
+struct comedi_file {
+ struct comedi_device *dev;
+ struct comedi_subdevice *read_subdev;
+ struct comedi_subdevice *write_subdev;
+ unsigned int last_detach_count;
+ bool last_attached:1;
+};
+
#define COMEDI_NUM_MINORS 0x100
#define COMEDI_NUM_SUBDEVICE_MINORS \
(COMEDI_NUM_MINORS - COMEDI_NUM_BOARD_MINORS)
@@ -239,6 +255,54 @@ comedi_write_subdevice(const struct comedi_device *dev, unsigned int minor)
return dev->write_subdev;
}
+static void comedi_file_reset(struct file *file)
+{
+ struct comedi_file *cfp = file->private_data;
+ struct comedi_device *dev = cfp->dev;
+ struct comedi_subdevice *s, *read_s, *write_s;
+ unsigned int minor = iminor(file_inode(file));
+
+ read_s = dev->read_subdev;
+ write_s = dev->write_subdev;
+ if (minor >= COMEDI_NUM_BOARD_MINORS) {
+ s = comedi_subdevice_from_minor(dev, minor);
+ if (s == NULL || s->subdev_flags & SDF_CMD_READ)
+ read_s = s;
+ if (s == NULL || s->subdev_flags & SDF_CMD_WRITE)
+ write_s = s;
+ }
+ cfp->last_attached = dev->attached;
+ cfp->last_detach_count = dev->detach_count;
+ ACCESS_ONCE(cfp->read_subdev) = read_s;
+ ACCESS_ONCE(cfp->write_subdev) = write_s;
+}
+
+static void comedi_file_check(struct file *file)
+{
+ struct comedi_file *cfp = file->private_data;
+ struct comedi_device *dev = cfp->dev;
+
+ if (cfp->last_attached != dev->attached ||
+ cfp->last_detach_count != dev->detach_count)
+ comedi_file_reset(file);
+}
+
+static struct comedi_subdevice *comedi_file_read_subdevice(struct file *file)
+{
+ struct comedi_file *cfp = file->private_data;
+
+ comedi_file_check(file);
+ return ACCESS_ONCE(cfp->read_subdev);
+}
+
+static struct comedi_subdevice *comedi_file_write_subdevice(struct file *file)
+{
+ struct comedi_file *cfp = file->private_data;
+
+ comedi_file_check(file);
+ return ACCESS_ONCE(cfp->write_subdev);
+}
+
static int resize_async_buffer(struct comedi_device *dev,
struct comedi_subdevice *s, unsigned new_size)
{
@@ -776,7 +840,6 @@ static int do_devinfo_ioctl(struct comedi_device *dev,
struct comedi_devinfo __user *arg,
struct file *file)
{
- const unsigned minor = iminor(file_inode(file));
struct comedi_subdevice *s;
struct comedi_devinfo devinfo;
@@ -788,13 +851,13 @@ static int do_devinfo_ioctl(struct comedi_device *dev,
strlcpy(devinfo.driver_name, dev->driver->driver_name, COMEDI_NAMELEN);
strlcpy(devinfo.board_name, dev->board_name, COMEDI_NAMELEN);
- s = comedi_read_subdevice(dev, minor);
+ s = comedi_file_read_subdevice(file);
if (s)
devinfo.read_subdevice = s->index;
else
devinfo.read_subdevice = -1;
- s = comedi_write_subdevice(dev, minor);
+ s = comedi_file_write_subdevice(file);
if (s)
devinfo.write_subdevice = s->index;
else
@@ -1787,8 +1850,9 @@ static int do_poll_ioctl(struct comedi_device *dev, unsigned long arg,
static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
- const unsigned minor = iminor(file_inode(file));
- struct comedi_device *dev = file->private_data;
+ unsigned minor = iminor(file_inode(file));
+ struct comedi_file *cfp = file->private_data;
+ struct comedi_device *dev = cfp->dev;
int rc;
mutex_lock(&dev->mutex);
@@ -1910,8 +1974,8 @@ static struct vm_operations_struct comedi_vm_ops = {
static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
{
- const unsigned minor = iminor(file_inode(file));
- struct comedi_device *dev = file->private_data;
+ struct comedi_file *cfp = file->private_data;
+ struct comedi_device *dev = cfp->dev;
struct comedi_subdevice *s;
struct comedi_async *async;
struct comedi_buf_map *bm = NULL;
@@ -1937,9 +2001,9 @@ static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
}
if (vma->vm_flags & VM_WRITE)
- s = comedi_write_subdevice(dev, minor);
+ s = comedi_file_write_subdevice(file);
else
- s = comedi_read_subdevice(dev, minor);
+ s = comedi_file_read_subdevice(file);
if (!s) {
retval = -EINVAL;
goto done;
@@ -2002,8 +2066,8 @@ static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
static unsigned int comedi_poll(struct file *file, poll_table *wait)
{
unsigned int mask = 0;
- const unsigned minor = iminor(file_inode(file));
- struct comedi_device *dev = file->private_data;
+ struct comedi_file *cfp = file->private_data;
+ struct comedi_device *dev = cfp->dev;
struct comedi_subdevice *s;
mutex_lock(&dev->mutex);
@@ -2013,7 +2077,7 @@ static unsigned int comedi_poll(struct file *file, poll_table *wait)
goto done;
}
- s = comedi_read_subdevice(dev, minor);
+ s = comedi_file_read_subdevice(file);
if (s && s->async) {
poll_wait(file, &s->async->wait_head, wait);
if (!s->busy || !comedi_is_subdevice_running(s) ||
@@ -2022,7 +2086,7 @@ static unsigned int comedi_poll(struct file *file, poll_table *wait)
mask |= POLLIN | POLLRDNORM;
}
- s = comedi_write_subdevice(dev, minor);
+ s = comedi_file_write_subdevice(file);
if (s && s->async) {
unsigned int bps = comedi_bytes_per_sample(s);
@@ -2046,8 +2110,8 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
struct comedi_async *async;
int n, m, count = 0, retval = 0;
DECLARE_WAITQUEUE(wait, current);
- const unsigned minor = iminor(file_inode(file));
- struct comedi_device *dev = file->private_data;
+ struct comedi_file *cfp = file->private_data;
+ struct comedi_device *dev = cfp->dev;
bool on_wait_queue = false;
bool attach_locked;
unsigned int old_detach_count;
@@ -2063,7 +2127,7 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
goto out;
}
- s = comedi_write_subdevice(dev, minor);
+ s = comedi_file_write_subdevice(file);
if (!s || !s->async) {
retval = -EIO;
goto out;
@@ -2115,7 +2179,7 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
* meantime!), but check the subdevice pointer
* as well just in case.
*/
- new_s = comedi_write_subdevice(dev, minor);
+ new_s = comedi_file_write_subdevice(file);
if (dev->attached &&
old_detach_count == dev->detach_count &&
s == new_s && new_s->async == async)
@@ -2190,8 +2254,8 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
struct comedi_async *async;
int n, m, count = 0, retval = 0;
DECLARE_WAITQUEUE(wait, current);
- const unsigned minor = iminor(file_inode(file));
- struct comedi_device *dev = file->private_data;
+ struct comedi_file *cfp = file->private_data;
+ struct comedi_device *dev = cfp->dev;
unsigned int old_detach_count;
bool become_nonbusy = false;
bool attach_locked;
@@ -2207,7 +2271,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
goto out;
}
- s = comedi_read_subdevice(dev, minor);
+ s = comedi_file_read_subdevice(file);
if (!s || !s->async) {
retval = -EIO;
goto out;
@@ -2304,7 +2368,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
* meantime!), but check the subdevice pointer as well just in
* case.
*/
- new_s = comedi_read_subdevice(dev, minor);
+ new_s = comedi_file_read_subdevice(file);
if (dev->attached && old_detach_count == dev->detach_count &&
s == new_s && new_s->async == async) {
if (become_nonbusy || comedi_buf_n_bytes_ready(s) == 0)
@@ -2322,6 +2386,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
static int comedi_open(struct inode *inode, struct file *file)
{
const unsigned minor = iminor(inode);
+ struct comedi_file *cfp;
struct comedi_device *dev = comedi_dev_get_from_minor(minor);
int rc;
@@ -2330,6 +2395,12 @@ static int comedi_open(struct inode *inode, struct file *file)
return -ENODEV;
}
+ cfp = kzalloc(sizeof(*cfp), GFP_KERNEL);
+ if (!cfp)
+ return -ENOMEM;
+
+ cfp->dev = dev;
+
mutex_lock(&dev->mutex);
if (!dev->attached && !capable(CAP_NET_ADMIN)) {
dev_dbg(dev->class_dev, "not attached and not CAP_NET_ADMIN\n");
@@ -2351,26 +2422,31 @@ static int comedi_open(struct inode *inode, struct file *file)
}
dev->use_count++;
- file->private_data = dev;
+ file->private_data = cfp;
+ comedi_file_reset(file);
rc = 0;
out:
mutex_unlock(&dev->mutex);
- if (rc)
+ if (rc) {
comedi_dev_put(dev);
+ kfree(cfp);
+ }
return rc;
}
static int comedi_fasync(int fd, struct file *file, int on)
{
- struct comedi_device *dev = file->private_data;
+ struct comedi_file *cfp = file->private_data;
+ struct comedi_device *dev = cfp->dev;
return fasync_helper(fd, file, on, &dev->async_queue);
}
static int comedi_close(struct inode *inode, struct file *file)
{
- struct comedi_device *dev = file->private_data;
+ struct comedi_file *cfp = file->private_data;
+ struct comedi_device *dev = cfp->dev;
struct comedi_subdevice *s = NULL;
int i;
@@ -2396,6 +2472,7 @@ static int comedi_close(struct inode *inode, struct file *file)
mutex_unlock(&dev->mutex);
comedi_dev_put(dev);
+ kfree(cfp);
return 0;
}