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path: root/drivers/char/tpm/tpm-dev-common.c
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Diffstat (limited to 'drivers/char/tpm/tpm-dev-common.c')
-rw-r--r--drivers/char/tpm/tpm-dev-common.c40
1 files changed, 18 insertions, 22 deletions
diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index 230b992880249..e4a04b2d3c32d 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -37,7 +37,7 @@ static void timeout_work(struct work_struct *work)
struct file_priv *priv = container_of(work, struct file_priv, work);
mutex_lock(&priv->buffer_mutex);
- atomic_set(&priv->data_pending, 0);
+ priv->data_pending = 0;
memset(priv->data_buffer, 0, sizeof(priv->data_buffer));
mutex_unlock(&priv->buffer_mutex);
}
@@ -46,7 +46,6 @@ void tpm_common_open(struct file *file, struct tpm_chip *chip,
struct file_priv *priv)
{
priv->chip = chip;
- atomic_set(&priv->data_pending, 0);
mutex_init(&priv->buffer_mutex);
timer_setup(&priv->user_read_timer, user_reader_timeout, 0);
INIT_WORK(&priv->work, timeout_work);
@@ -58,29 +57,24 @@ ssize_t tpm_common_read(struct file *file, char __user *buf,
size_t size, loff_t *off)
{
struct file_priv *priv = file->private_data;
- ssize_t ret_size;
- ssize_t orig_ret_size;
+ ssize_t ret_size = 0;
int rc;
del_singleshot_timer_sync(&priv->user_read_timer);
flush_work(&priv->work);
- ret_size = atomic_read(&priv->data_pending);
- if (ret_size > 0) { /* relay data */
- orig_ret_size = ret_size;
- if (size < ret_size)
- ret_size = size;
+ mutex_lock(&priv->buffer_mutex);
- mutex_lock(&priv->buffer_mutex);
+ if (priv->data_pending) {
+ ret_size = min_t(ssize_t, size, priv->data_pending);
rc = copy_to_user(buf, priv->data_buffer, ret_size);
- memset(priv->data_buffer, 0, orig_ret_size);
+ memset(priv->data_buffer, 0, priv->data_pending);
if (rc)
ret_size = -EFAULT;
- mutex_unlock(&priv->buffer_mutex);
+ priv->data_pending = 0;
}
- atomic_set(&priv->data_pending, 0);
-
+ mutex_unlock(&priv->buffer_mutex);
return ret_size;
}
@@ -91,17 +85,19 @@ ssize_t tpm_common_write(struct file *file, const char __user *buf,
size_t in_size = size;
ssize_t out_size;
+ if (in_size > TPM_BUFSIZE)
+ return -E2BIG;
+
+ mutex_lock(&priv->buffer_mutex);
+
/* Cannot perform a write until the read has cleared either via
* tpm_read or a user_read_timer timeout. This also prevents split
* buffered writes from blocking here.
*/
- if (atomic_read(&priv->data_pending) != 0)
+ if (priv->data_pending != 0) {
+ mutex_unlock(&priv->buffer_mutex);
return -EBUSY;
-
- if (in_size > TPM_BUFSIZE)
- return -E2BIG;
-
- mutex_lock(&priv->buffer_mutex);
+ }
if (copy_from_user
(priv->data_buffer, (void __user *) buf, in_size)) {
@@ -132,7 +128,7 @@ ssize_t tpm_common_write(struct file *file, const char __user *buf,
return out_size;
}
- atomic_set(&priv->data_pending, out_size);
+ priv->data_pending = out_size;
mutex_unlock(&priv->buffer_mutex);
/* Set a timeout by which the reader must come claim the result */
@@ -149,5 +145,5 @@ void tpm_common_release(struct file *file, struct file_priv *priv)
del_singleshot_timer_sync(&priv->user_read_timer);
flush_work(&priv->work);
file->private_data = NULL;
- atomic_set(&priv->data_pending, 0);
+ priv->data_pending = 0;
}