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authorStefan Berger <stefanb@linux.vnet.ibm.com>2016-02-29 08:53:02 -0500
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2016-06-25 17:26:35 +0300
commit15516788e581eb32ec1c50e5f00aba3faf95d817 (patch)
treefc21e9a76367a73ba36b1e9315ca8fd741c544d8 /drivers/char/tpm/tpm-chip.c
parent3897cd9c8d1d1a9ff81fed893502911c2b9f4a79 (diff)
tpm: Replace device number bitmap with IDR
Replace the device number bitmap with IDR. Extend the number of devices we can create to 64k. Since an IDR allows us to associate a pointer with an ID, we use this now to rewrite tpm_chip_find_get() to simply look up the chip pointer by the given device ID. Protect the IDR calls with a mutex. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Diffstat (limited to 'drivers/char/tpm/tpm-chip.c')
-rw-r--r--drivers/char/tpm/tpm-chip.c84
1 files changed, 45 insertions, 39 deletions
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 588037733107..f62c8518cd68 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -29,9 +29,8 @@
#include "tpm.h"
#include "tpm_eventlog.h"
-static DECLARE_BITMAP(dev_mask, TPM_NUM_DEVICES);
-static LIST_HEAD(tpm_chip_list);
-static DEFINE_SPINLOCK(driver_lock);
+DEFINE_IDR(dev_nums_idr);
+static DEFINE_MUTEX(idr_lock);
struct class *tpm_class;
dev_t tpm_devt;
@@ -88,20 +87,30 @@ EXPORT_SYMBOL_GPL(tpm_put_ops);
*/
struct tpm_chip *tpm_chip_find_get(int chip_num)
{
- struct tpm_chip *pos, *chip = NULL;
+ struct tpm_chip *chip, *res = NULL;
+ int chip_prev;
+
+ mutex_lock(&idr_lock);
+
+ if (chip_num == TPM_ANY_NUM) {
+ chip_num = 0;
+ do {
+ chip_prev = chip_num;
+ chip = idr_get_next(&dev_nums_idr, &chip_num);
+ if (chip && !tpm_try_get_ops(chip)) {
+ res = chip;
+ break;
+ }
+ } while (chip_prev != chip_num);
+ } else {
+ chip = idr_find_slowpath(&dev_nums_idr, chip_num);
+ if (chip && !tpm_try_get_ops(chip))
+ res = chip;
+ }
- rcu_read_lock();
- list_for_each_entry_rcu(pos, &tpm_chip_list, list) {
- if (chip_num != TPM_ANY_NUM && chip_num != pos->dev_num)
- continue;
+ mutex_unlock(&idr_lock);
- /* rcu prevents chip from being free'd */
- if (!tpm_try_get_ops(pos))
- chip = pos;
- break;
- }
- rcu_read_unlock();
- return chip;
+ return res;
}
/**
@@ -114,9 +123,10 @@ static void tpm_dev_release(struct device *dev)
{
struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
- spin_lock(&driver_lock);
- clear_bit(chip->dev_num, dev_mask);
- spin_unlock(&driver_lock);
+ mutex_lock(&idr_lock);
+ idr_remove(&dev_nums_idr, chip->dev_num);
+ mutex_unlock(&idr_lock);
+
kfree(chip);
}
@@ -142,21 +152,18 @@ struct tpm_chip *tpm_chip_alloc(struct device *dev,
mutex_init(&chip->tpm_mutex);
init_rwsem(&chip->ops_sem);
- INIT_LIST_HEAD(&chip->list);
chip->ops = ops;
- spin_lock(&driver_lock);
- chip->dev_num = find_first_zero_bit(dev_mask, TPM_NUM_DEVICES);
- spin_unlock(&driver_lock);
-
- if (chip->dev_num >= TPM_NUM_DEVICES) {
+ mutex_lock(&idr_lock);
+ rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
+ mutex_unlock(&idr_lock);
+ if (rc < 0) {
dev_err(dev, "No available tpm device numbers\n");
kfree(chip);
- return ERR_PTR(-ENOMEM);
+ return ERR_PTR(rc);
}
-
- set_bit(chip->dev_num, dev_mask);
+ chip->dev_num = rc;
device_initialize(&chip->dev);
@@ -242,19 +249,28 @@ static int tpm_add_char_device(struct tpm_chip *chip)
return rc;
}
+ /* Make the chip available. */
+ mutex_lock(&idr_lock);
+ idr_replace(&dev_nums_idr, chip, chip->dev_num);
+ mutex_unlock(&idr_lock);
+
return rc;
}
static void tpm_del_char_device(struct tpm_chip *chip)
{
cdev_del(&chip->cdev);
+ device_del(&chip->dev);
+
+ /* Make the chip unavailable. */
+ mutex_lock(&idr_lock);
+ idr_replace(&dev_nums_idr, NULL, chip->dev_num);
+ mutex_unlock(&idr_lock);
/* Make the driver uncallable. */
down_write(&chip->ops_sem);
chip->ops = NULL;
up_write(&chip->ops_sem);
-
- device_del(&chip->dev);
}
static int tpm1_chip_register(struct tpm_chip *chip)
@@ -309,11 +325,6 @@ int tpm_chip_register(struct tpm_chip *chip)
if (rc)
goto out_err;
- /* Make the chip available. */
- spin_lock(&driver_lock);
- list_add_tail_rcu(&chip->list, &tpm_chip_list);
- spin_unlock(&driver_lock);
-
chip->flags |= TPM_CHIP_FLAG_REGISTERED;
if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
@@ -350,11 +361,6 @@ void tpm_chip_unregister(struct tpm_chip *chip)
if (!(chip->flags & TPM_CHIP_FLAG_REGISTERED))
return;
- spin_lock(&driver_lock);
- list_del_rcu(&chip->list);
- spin_unlock(&driver_lock);
- synchronize_rcu();
-
if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
sysfs_remove_link(&chip->dev.parent->kobj, "ppi");

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