X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Fring_buffer_backend.c;h=3cc22d77b2d9ad5c2ed428fed783b9055a5f97d3;hb=5140d2b3070f211e6d8a0ad7cb0a190e8b6f3e28;hp=8e1a796a55071abb6f388b2c9ed11cc34b7ed845;hpb=16f78f3ad7dea4a0b442b8c7e0de01935f28e656;p=lttng-modules.git

diff --git a/lib/ringbuffer/ring_buffer_backend.c b/lib/ringbuffer/ring_buffer_backend.c
index 8e1a796a..3cc22d77 100644
--- a/lib/ringbuffer/ring_buffer_backend.c
+++ b/lib/ringbuffer/ring_buffer_backend.c
@@ -331,6 +331,12 @@ int channel_backend_init(struct channel_backend *chanb,
 		return -EINVAL;
 	if (!num_subbuf || (num_subbuf & (num_subbuf - 1)))
 		return -EINVAL;
+	/*
+	 * Overwrite mode buffers require at least 2 subbuffers per
+	 * buffer.
+	 */
+	if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2)
+		return -EINVAL;
 
 	ret = subbuffer_id_check_index(config, num_subbuf);
 	if (ret)
@@ -478,7 +484,7 @@ void channel_backend_free(struct channel_backend *chanb)
  * @pagecpy : page size copied so far
  */
 void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset,
-			    const void *src, size_t len, ssize_t pagecpy)
+			    const void *src, size_t len, size_t pagecpy)
 {
 	struct channel_backend *chanb = &bufb->chan->backend;
 	const struct lib_ring_buffer_config *config = &chanb->config;
@@ -524,7 +530,7 @@ EXPORT_SYMBOL_GPL(_lib_ring_buffer_write);
  */
 void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb,
 			     size_t offset,
-			     int c, size_t len, ssize_t pagecpy)
+			     int c, size_t len, size_t pagecpy)
 {
 	struct channel_backend *chanb = &bufb->chan->backend;
 	const struct lib_ring_buffer_config *config = &chanb->config;
@@ -654,7 +660,7 @@ EXPORT_SYMBOL_GPL(_lib_ring_buffer_strcpy);
 void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb,
 				      size_t offset,
 				      const void __user *src, size_t len,
-				      ssize_t pagecpy)
+				      size_t pagecpy)
 {
 	struct channel_backend *chanb = &bufb->chan->backend;
 	const struct lib_ring_buffer_config *config = &chanb->config;
@@ -795,8 +801,7 @@ size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset,
 {
 	struct channel_backend *chanb = &bufb->chan->backend;
 	const struct lib_ring_buffer_config *config = &chanb->config;
-	size_t index;
-	ssize_t pagecpy, orig_len;
+	size_t index, pagecpy, orig_len;
 	struct lib_ring_buffer_backend_pages *rpages;
 	unsigned long sb_bindex, id;