generic_data_done: mark lost blocks in the alarm field

This also reorganizes generic_data_done to exploit symmetry between
input and output csets. Actually, we didn't update seq_num or the
timestamp for output, but now we have the current control in sysfs,
so we'd better update it every time.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Federico Vaga <federico.vaga@gmail.com>

helpers.c

@@ -84,13 +84,10 @@ static int __zio_arm_input_trigger(struct zio_ti *ti)
 	/* Allocate the buffer for the incoming sample, in active channels */
 	chan_for_each(chan, cset) {
 		ctrl = chan->current_ctrl;
-		ctrl->seq_num++;
-
 		ctrl->nsamples = ti->nsamples;
 		datalen = ctrl->ssize * ti->nsamples;
-		block = zbuf->b_op->alloc_block(chan->bi, datalen,
-						GFP_ATOMIC);
-		/* on error it returns NULL so we are all happy */
+		block = zbuf->b_op->alloc_block(chan->bi, datalen, GFP_ATOMIC);
+		/* If alloc error, it is reported at data_done time */
 		chan->active_block = block;
 	}
 	i = cset->raw_io(cset);

include/linux/zio-trigger.h

@@ -117,46 +117,50 @@ int zio_trigger_abort_disable(struct zio_cset *cset, int disable);
 static inline void zio_generic_data_done(struct zio_cset *cset)
 {
 	struct zio_buffer_type *zbuf;
-	struct zio_device *zdev;
 	struct zio_channel *chan;
 	struct zio_block *block;
+	struct zio_control *ctrl;
 	struct zio_ti *ti;
 	struct zio_bi *bi;
 
 	pr_debug("%s:%d\n", __func__, __LINE__);
 
 	ti = cset->ti;
-	zdev = cset->zdev;
 	zbuf = cset->zbuf;
 
-	if (unlikely((ti->flags & ZIO_DIR) == ZIO_DIR_OUTPUT)) {
-		chan_for_each(chan, cset) {
-			bi = chan->bi;
-			block = chan->active_block;
-			if (block)
-				zbuf->b_op->free_block(chan->bi, block);
-			/* We may have a new block ready, or not */
-			chan->active_block = zbuf->b_op->retr_block(chan->bi);
-		}
-		return;
-	}
-	/* DIR_INPUT */
+	/* Input and output are very similar by now */
 	chan_for_each(chan, cset) {
 		bi = chan->bi;
 		block = chan->active_block;
-		if (!block)
+		ctrl = chan->current_ctrl;
+
+		/* Update the current control: sequence and timestamp */
+		ctrl->seq_num++;
+		ctrl->tstamp.secs = ti->tstamp.tv_sec;
+		ctrl->tstamp.ticks = ti->tstamp.tv_nsec;
+		ctrl->tstamp.bins = ti->tstamp_extra;
+
+		if (!block) {
+			ctrl->zio_alarms |= ZIO_ALARM_LOST_BLOCK;
 			continue;
-		/* Copy the stamp: it is cset-wide so it lives in the trigger */
-		chan->current_ctrl->tstamp.secs = ti->tstamp.tv_sec;
-		chan->current_ctrl->tstamp.ticks = ti->tstamp.tv_nsec;
-		chan->current_ctrl->tstamp.bins = ti->tstamp_extra;
-		memcpy(zio_get_ctrl(block), chan->current_ctrl,
-			zio_control_size(chan));
-
-		if (zbuf->b_op->store_block(bi, block)) /* may fail, no prob */
-			zbuf->b_op->free_block(bi, block);
+		}
+
+		if (unlikely((ti->flags & ZIO_DIR) == ZIO_DIR_OUTPUT)) {
+				zbuf->b_op->free_block(chan->bi, block);
+		} else { /* DIR_INPUT */
+			memcpy(zio_get_ctrl(block), ctrl,
+			       zio_control_size(chan));
+			if (zbuf->b_op->store_block(bi, block))
+				zbuf->b_op->free_block(bi, block);
+		}
 		chan->active_block = NULL;
 	}
+	if (likely((ti->flags & ZIO_DIR) == ZIO_DIR_INPUT))
+		return;
+
+	/* Only for output: prepare the next event if any is ready */
+	chan_for_each(chan, cset)
+		chan->active_block = zbuf->b_op->retr_block(chan->bi);
 }
 
 #endif /* __ZIO_TRIGGER_H__ */