This patch removes the BKL calls from the TPM driver, which
were added in the overall misc-char-dev-BKL-pushdown.patch,
as they are not needed. Changed num_opens from an int to atomic_t.
Signed-off-by: Mimi Zohar <[email protected]>
Signed-off-by: Rajiv Andrade <[email protected]>
---
drivers/char/tpm/tpm.c | 22 +++++++---------------
drivers/char/tpm/tpm.h | 2 +-
2 files changed, 8 insertions(+), 16 deletions(-)
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index ae766d8..cd4ff36 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -960,7 +960,6 @@ int tpm_open(struct inode *inode, struct file *file)
int rc = 0, minor = iminor(inode);
struct tpm_chip *chip = NULL, *pos;
- lock_kernel();
spin_lock(&driver_lock);
list_for_each_entry(pos, &tpm_chip_list, list) {
@@ -975,34 +974,31 @@ int tpm_open(struct inode *inode, struct file *file)
goto err_out;
}
- if (chip->num_opens) {
+ if (atomic_read(&chip->num_opens)) {
dev_dbg(chip->dev, "Another process owns this TPM\n");
rc = -EBUSY;
goto err_out;
}
- chip->num_opens++;
+ atomic_inc(&chip->num_opens);
get_device(chip->dev);
spin_unlock(&driver_lock);
chip->data_buffer = kmalloc(TPM_BUFSIZE * sizeof(u8), GFP_KERNEL);
if (chip->data_buffer == NULL) {
- chip->num_opens--;
+ atomic_dec(&chip->num_opens);
put_device(chip->dev);
- unlock_kernel();
return -ENOMEM;
}
atomic_set(&chip->data_pending, 0);
file->private_data = chip;
- unlock_kernel();
return 0;
err_out:
spin_unlock(&driver_lock);
- unlock_kernel();
return rc;
}
EXPORT_SYMBOL_GPL(tpm_open);
@@ -1016,7 +1012,7 @@ int tpm_release(struct inode *inode, struct file *file)
file->private_data = NULL;
del_singleshot_timer_sync(&chip->user_read_timer);
atomic_set(&chip->data_pending, 0);
- chip->num_opens--;
+ atomic_dec(chip->num_opens);
put_device(chip->dev);
kfree(chip->data_buffer);
spin_unlock(&driver_lock);
@@ -1231,20 +1227,16 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend
return NULL;
}
- spin_lock(&driver_lock);
-
- list_add(&chip->list, &tpm_chip_list);
-
- spin_unlock(&driver_lock);
-
if (sysfs_create_group(&dev->kobj, chip->vendor.attr_group)) {
- list_del(&chip->list);
misc_deregister(&chip->vendor.miscdev);
put_device(chip->dev);
return NULL;
}
chip->bios_dir = tpm_bios_log_setup(devname);
+ spin_lock(&driver_lock);
+ list_add(&chip->list, &tpm_chip_list);
+ spin_unlock(&driver_lock);
return chip;
}
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index e885148..edb8ed6 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -90,7 +90,7 @@ struct tpm_chip {
struct device *dev; /* Device stuff */
int dev_num; /* /dev/tpm# */
- int num_opens; /* only one allowed */
+ atomic_t num_opens; /* only one allowed */
int time_expired;
/* Data passed to and from the tpm via the read/write calls */
--
1.5.4.5
Quoting Rajiv Andrade ([email protected]):
> This patch removes the BKL calls from the TPM driver, which
> were added in the overall misc-char-dev-BKL-pushdown.patch,
> as they are not needed. Changed num_opens from an int to atomic_t.
>
> Signed-off-by: Mimi Zohar <[email protected]>
> Signed-off-by: Rajiv Andrade <[email protected]>
Yes, this patch is good.
It would also be good to rename num_opens. Note that it is always
either 0 or 1, and indicates whether someone has opened the chip.
So 'is_open' may make more sense.
Mimi is also working on a patch (on top of this one) to use rcu
to protect chip->list, and that patch will (I hope) include an
explanation of all of the locking/protection involved.
Acked-by: Serge Hallyn <[email protected]>
> ---
> drivers/char/tpm/tpm.c | 22 +++++++---------------
> drivers/char/tpm/tpm.h | 2 +-
> 2 files changed, 8 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
> index ae766d8..cd4ff36 100644
> --- a/drivers/char/tpm/tpm.c
> +++ b/drivers/char/tpm/tpm.c
> @@ -960,7 +960,6 @@ int tpm_open(struct inode *inode, struct file *file)
> int rc = 0, minor = iminor(inode);
> struct tpm_chip *chip = NULL, *pos;
>
> - lock_kernel();
> spin_lock(&driver_lock);
>
> list_for_each_entry(pos, &tpm_chip_list, list) {
> @@ -975,34 +974,31 @@ int tpm_open(struct inode *inode, struct file *file)
> goto err_out;
> }
>
> - if (chip->num_opens) {
> + if (atomic_read(&chip->num_opens)) {
> dev_dbg(chip->dev, "Another process owns this TPM\n");
> rc = -EBUSY;
> goto err_out;
> }
>
> - chip->num_opens++;
> + atomic_inc(&chip->num_opens);
> get_device(chip->dev);
>
> spin_unlock(&driver_lock);
>
> chip->data_buffer = kmalloc(TPM_BUFSIZE * sizeof(u8), GFP_KERNEL);
> if (chip->data_buffer == NULL) {
> - chip->num_opens--;
> + atomic_dec(&chip->num_opens);
> put_device(chip->dev);
> - unlock_kernel();
> return -ENOMEM;
> }
>
> atomic_set(&chip->data_pending, 0);
>
> file->private_data = chip;
> - unlock_kernel();
> return 0;
>
> err_out:
> spin_unlock(&driver_lock);
> - unlock_kernel();
> return rc;
> }
> EXPORT_SYMBOL_GPL(tpm_open);
> @@ -1016,7 +1012,7 @@ int tpm_release(struct inode *inode, struct file *file)
> file->private_data = NULL;
> del_singleshot_timer_sync(&chip->user_read_timer);
> atomic_set(&chip->data_pending, 0);
> - chip->num_opens--;
> + atomic_dec(chip->num_opens);
> put_device(chip->dev);
> kfree(chip->data_buffer);
> spin_unlock(&driver_lock);
> @@ -1231,20 +1227,16 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend
> return NULL;
> }
>
> - spin_lock(&driver_lock);
> -
> - list_add(&chip->list, &tpm_chip_list);
> -
> - spin_unlock(&driver_lock);
> -
> if (sysfs_create_group(&dev->kobj, chip->vendor.attr_group)) {
> - list_del(&chip->list);
> misc_deregister(&chip->vendor.miscdev);
> put_device(chip->dev);
> return NULL;
> }
>
> chip->bios_dir = tpm_bios_log_setup(devname);
> + spin_lock(&driver_lock);
> + list_add(&chip->list, &tpm_chip_list);
> + spin_unlock(&driver_lock);
>
> return chip;
> }
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index e885148..edb8ed6 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -90,7 +90,7 @@ struct tpm_chip {
> struct device *dev; /* Device stuff */
>
> int dev_num; /* /dev/tpm# */
> - int num_opens; /* only one allowed */
> + atomic_t num_opens; /* only one allowed */
> int time_expired;
>
> /* Data passed to and from the tpm via the read/write calls */
> --
> 1.5.4.5
>
>
On Fri, 22 Aug 2008, Serge E. Hallyn wrote:
> Quoting Rajiv Andrade ([email protected]):
> > This patch removes the BKL calls from the TPM driver, which
> > were added in the overall misc-char-dev-BKL-pushdown.patch,
> > as they are not needed. Changed num_opens from an int to atomic_t.
> >
> > Signed-off-by: Mimi Zohar <[email protected]>
> > Signed-off-by: Rajiv Andrade <[email protected]>
>
> Yes, this patch is good.
>
> It would also be good to rename num_opens. Note that it is always
> either 0 or 1, and indicates whether someone has opened the chip.
> So 'is_open' may make more sense.
And use atomic_set() instead of atomic_inc().
- James
--
James Morris
<[email protected]>