X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=drivers%2Fchar%2Ftpm%2Ftpm.c;h=0d91655f3ee2d137fd364d17089f69e3f97abe0d;hp=361a1dff8f772e9d1aa2d855300046ca50291c03;hb=4be11470a33359ac885539737a79dac6ba9f3495;hpb=cf5e15fbd72c13977720aa15b7b7e00e1d8fd8f2

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 361a1dff8f77..0d91655f3ee2 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -1072,17 +1072,20 @@ ssize_t tpm_write(struct file *file, const char __user *buf,
 		  size_t size, loff_t *off)
 {
 	struct tpm_chip *chip = file->private_data;
-	size_t in_size = size, out_size;
+	size_t in_size = size;
+	ssize_t out_size;
 
 	/* cannot perform a write until the read has cleared
-	   either via tpm_read or a user_read_timer timeout */
-	while (atomic_read(&chip->data_pending) != 0)
-		msleep(TPM_TIMEOUT);
-
-	mutex_lock(&chip->buffer_mutex);
+	   either via tpm_read or a user_read_timer timeout.
+	   This also prevents splitted buffered writes from blocking here.
+	*/
+	if (atomic_read(&chip->data_pending) != 0)
+		return -EBUSY;
 
 	if (in_size > TPM_BUFSIZE)
-		in_size = TPM_BUFSIZE;
+		return -E2BIG;
+
+	mutex_lock(&chip->buffer_mutex);
 
 	if (copy_from_user
 	    (chip->data_buffer, (void __user *) buf, in_size)) {
@@ -1092,6 +1095,10 @@ ssize_t tpm_write(struct file *file, const char __user *buf,
 
 	/* atomic tpm command send and result receive */
 	out_size = tpm_transmit(chip, chip->data_buffer, TPM_BUFSIZE);
+	if (out_size < 0) {
+		mutex_unlock(&chip->buffer_mutex);
+		return out_size;
+	}
 
 	atomic_set(&chip->data_pending, out_size);
 	mutex_unlock(&chip->buffer_mutex);
@@ -1115,12 +1122,13 @@ ssize_t tpm_read(struct file *file, char __user *buf,
 	ret_size = atomic_read(&chip->data_pending);
 	atomic_set(&chip->data_pending, 0);
 	if (ret_size > 0) {	/* relay data */
+		ssize_t orig_ret_size = ret_size;
 		if (size < ret_size)
 			ret_size = size;
 
 		mutex_lock(&chip->buffer_mutex);
 		rc = copy_to_user(buf, chip->data_buffer, ret_size);
-		memset(chip->data_buffer, 0, ret_size);
+		memset(chip->data_buffer, 0, orig_ret_size);
 		if (rc)
 			ret_size = -EFAULT;