Merge tag 'tpmdd-next-20180602' of git://git.infradead.org/users/jjs/linux-tpmdd into next-tpm

tpmdd fixes for Linux 4.17 (just missed 4.17)

2 files changed, 19 insertions, 23 deletions

diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index 230b99288024..e4a04b2d3c32 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;
 }
diff --git a/drivers/char/tpm/tpm-dev.h b/drivers/char/tpm/tpm-dev.h
index ba3b6f9dacf7..b24cfb4d3ee1 100644
--- a/drivers/char/tpm/tpm-dev.h
+++ b/drivers/char/tpm/tpm-dev.h
@@ -8,7 +8,7 @@ struct file_priv {
         struct tpm_chip *chip;
 
         /* Data passed to and from the tpm via the read/write calls */
-        atomic_t data_pending;
+        size_t data_pending;
         struct mutex buffer_mutex;
 
         struct timer_list user_read_timer;      /* user needs to claim result */