FTL: Add internal band state changes

Signed-off-by: Kozlowski Mateusz <mateusz.kozlowski@intel.com>
Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Change-Id: Icaecc4e77996919a23f70c1ffad15b783741fd5e
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/13327
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

lib/ftl/ftl_band.c

@@ -59,6 +59,52 @@ ftl_band_free_md_entry(struct ftl_band *band)
 	p2l_map->band_dma_md = NULL;
 }
 
+static void
+_ftl_band_set_free(struct ftl_band *band)
+{
+	struct spdk_ftl_dev *dev = band->dev;
+
+	/* Add the band to the free band list */
+	TAILQ_INSERT_TAIL(&dev->free_bands, band, queue_entry);
+
+	dev->num_free++;
+	ftl_apply_limits(dev);
+}
+
+static void
+_ftl_band_set_preparing(struct ftl_band *band)
+{
+	struct spdk_ftl_dev *dev = band->dev;
+
+	/* Remove band from free list */
+	TAILQ_REMOVE(&dev->free_bands, band, queue_entry);
+
+	band->md->wr_cnt++;
+
+	assert(dev->num_free > 0);
+	dev->num_free--;
+
+	ftl_apply_limits(dev);
+}
+
+static void
+_ftl_band_set_closed(struct ftl_band *band)
+{
+	struct spdk_ftl_dev *dev = band->dev;
+
+	/* Set the state as free_md() checks for that */
+	band->md->state = FTL_BAND_STATE_CLOSED;
+	if (band->owner.state_change_fn) {
+		band->owner.state_change_fn(band);
+	}
+
+	/* Free the p2l map if there are no outstanding IOs */
+	ftl_band_release_p2l_map(band);
+	assert(band->p2l_map.ref_cnt == 0);
+
+	TAILQ_INSERT_TAIL(&dev->shut_bands, band, queue_entry);
+}
+
 ftl_addr
 ftl_band_tail_md_addr(struct ftl_band *band)
 {
@@ -72,6 +118,46 @@ ftl_band_tail_md_addr(struct ftl_band *band)
 	return addr;
 }
 
+void
+ftl_band_set_state(struct ftl_band *band, enum ftl_band_state state)
+{
+	switch (state) {
+	case FTL_BAND_STATE_FREE:
+		assert(band->md->state == FTL_BAND_STATE_CLOSED);
+		_ftl_band_set_free(band);
+
+		band->md->p2l_map_checksum = 0;
+		break;
+
+	case FTL_BAND_STATE_PREP:
+		assert(band->md->state == FTL_BAND_STATE_FREE);
+		_ftl_band_set_preparing(band);
+		break;
+
+	case FTL_BAND_STATE_CLOSED:
+		if (band->md->state != FTL_BAND_STATE_CLOSED) {
+			assert(band->md->state == FTL_BAND_STATE_CLOSING);
+			_ftl_band_set_closed(band);
+			return; /* state can be changed asynchronously */
+		}
+		break;
+
+	case FTL_BAND_STATE_OPEN:
+		band->md->p2l_map_checksum = 0;
+		break;
+	case FTL_BAND_STATE_OPENING:
+	case FTL_BAND_STATE_FULL:
+	case FTL_BAND_STATE_CLOSING:
+		break;
+	default:
+		FTL_ERRLOG(band->dev, "Unknown band state, %u", state);
+		assert(false);
+		break;
+	}
+
+	band->md->state = state;
+}
+
 void
 ftl_band_set_type(struct ftl_band *band, enum ftl_band_type type)
 {

lib/ftl/ftl_core.c

@@ -26,6 +26,15 @@ spdk_ftl_io_size(void)
 	return sizeof(struct ftl_io);
 }
 
+static void
+ftl_band_erase(struct ftl_band *band)
+{
+	assert(band->md->state == FTL_BAND_STATE_CLOSED ||
+	       band->md->state == FTL_BAND_STATE_FREE);
+
+	ftl_band_set_state(band, FTL_BAND_STATE_PREP);
+}
+
 static size_t
 ftl_get_limit(const struct spdk_ftl_dev *dev, int type)
 {
@@ -263,6 +272,20 @@ ftl_core_poller(void *ctx)
 	return SPDK_POLLER_IDLE;
 }
 
+struct ftl_band *
+ftl_band_get_next_free(struct spdk_ftl_dev *dev)
+{
+	struct ftl_band *band = NULL;
+
+	if (!TAILQ_EMPTY(&dev->free_bands)) {
+		band = TAILQ_FIRST(&dev->free_bands);
+		TAILQ_REMOVE(&dev->free_bands, band, queue_entry);
+		ftl_band_erase(band);
+	}
+
+	return band;
+}
+
 void *g_ftl_write_buf;
 void *g_ftl_read_buf;
 

lib/ftl/ftl_core.h

@@ -150,6 +150,8 @@ int ftl_io_channel_poll(void *arg);
 
 struct ftl_io_channel *ftl_io_channel_get_ctx(struct spdk_io_channel *ioch);
 
+struct ftl_band *ftl_band_get_next_free(struct spdk_ftl_dev *dev);
+
 static inline uint64_t
 ftl_get_num_blocks_in_band(const struct spdk_ftl_dev *dev)
 {

lib/ftl/ftl_io.c

@@ -10,6 +10,7 @@
 
 #include "ftl_io.h"
 #include "ftl_core.h"
+#include "ftl_band.h"
 #include "ftl_debug.h"
 
 void
@@ -238,4 +239,5 @@ ftl_io_clear(struct ftl_io *io)
 	io->done = false;
 	io->status = 0;
 	io->flags = 0;
+	io->band = NULL;
 }

lib/ftl/ftl_io.h

@@ -88,6 +88,9 @@ struct ftl_io {
 	/* Offset within the iovec (in blocks) */
 	size_t				iov_off;
 
+	/* Band this IO is being written to */
+	struct ftl_band			*band;
+
 	/* Request status */
 	int				status;