X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Fbackend.h;h=bbbc80d8eb03be444d4890d828d92f7f6eb118ab;hb=61eb4c393f32dbea95e9125c6ec4d8cdad535f70;hp=ed913325e2ddb70070392226cc9b27b39df18fad;hpb=5e3912524c2841304e38f962dd8d4cfc6150909e;p=lttng-modules.git

diff --git a/lib/ringbuffer/backend.h b/lib/ringbuffer/backend.h
index ed913325..bbbc80d8 100644
--- a/lib/ringbuffer/backend.h
+++ b/lib/ringbuffer/backend.h
@@ -96,6 +96,8 @@ void lib_ring_buffer_write(const struct lib_ring_buffer_config *config,
 	struct lib_ring_buffer_backend_pages *rpages;
 	unsigned long sb_bindex, id;
 
+	if (unlikely(!len))
+		return;
 	offset &= chanb->buf_size - 1;
 	sbidx = offset >> chanb->subbuf_size_order;
 	index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
@@ -142,6 +144,8 @@ void lib_ring_buffer_memset(const struct lib_ring_buffer_config *config,
 	struct lib_ring_buffer_backend_pages *rpages;
 	unsigned long sb_bindex, id;
 
+	if (unlikely(!len))
+		return;
 	offset &= chanb->buf_size - 1;
 	sbidx = offset >> chanb->subbuf_size_order;
 	index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
@@ -189,6 +193,8 @@ void lib_ring_buffer_copy_from_user_inatomic(const struct lib_ring_buffer_config
 	unsigned long ret;
 	mm_segment_t old_fs = get_fs();
 
+	if (unlikely(!len))
+		return;
 	offset &= chanb->buf_size - 1;
 	sbidx = offset >> chanb->subbuf_size_order;
 	index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;