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Diffstat (limited to 'fs/pipe.c')
-rw-r--r--fs/pipe.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index 0f9fd897ceb5..620a113f92eb 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -314,6 +314,30 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 		unsigned int tail = pipe->tail;
 		unsigned int mask = pipe->ring_size - 1;
 
+#ifdef CONFIG_WATCH_QUEUE
+		if (pipe->note_loss) {
+			struct watch_notification n;
+
+			if (total_len < 8) {
+				if (ret == 0)
+					ret = -ENOBUFS;
+				break;
+			}
+
+			n.type = WATCH_TYPE_META;
+			n.subtype = WATCH_META_LOSS_NOTIFICATION;
+			n.info = watch_sizeof(n);
+			if (copy_to_iter(&n, sizeof(n), to) != sizeof(n)) {
+				if (ret == 0)
+					ret = -EFAULT;
+				break;
+			}
+			ret += sizeof(n);
+			total_len -= sizeof(n);
+			pipe->note_loss = false;
+		}
+#endif
+
 		if (!pipe_empty(head, tail)) {
 			struct pipe_buffer *buf = &pipe->bufs[tail & mask];
 			size_t chars = buf->len;
@@ -355,6 +379,10 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 			if (!buf->len) {
 				pipe_buf_release(pipe, buf);
 				spin_lock_irq(&pipe->rd_wait.lock);
+#ifdef CONFIG_WATCH_QUEUE
+				if (buf->flags & PIPE_BUF_FLAG_LOSS)
+					pipe->note_loss = true;
+#endif
 				tail++;
 				pipe->tail = tail;
 				spin_unlock_irq(&pipe->rd_wait.lock);