From b97bb6f53b43c98b67f39f75b23dfff91c8d85eb Mon Sep 17 00:00:00 2001
From: Adam Rutkowski <adam.j.rutkowski@intel.com>
Date: Tue, 4 Jun 2019 13:29:45 -0400
Subject: [PATCH] Add function to check for lazy write cache mode (WO or WB)

Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
---
 inc/ocf_mngt.h            | 11 +++++++++++
 src/engine/cache_engine.h |  7 +++++++
 src/mngt/ocf_mngt_cache.c |  4 +++-
 src/ocf_core.c            |  9 +++++++--
 4 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/inc/ocf_mngt.h b/inc/ocf_mngt.h
index c82ee2c..dae9e25 100644
--- a/inc/ocf_mngt.h
+++ b/inc/ocf_mngt.h
@@ -695,6 +695,17 @@ typedef void (*ocf_mngt_cache_save_end_t)(ocf_cache_t cache,
 void ocf_mngt_cache_save(ocf_cache_t cache,
 		ocf_mngt_cache_save_end_t cmpl, void *priv);
 
+/**
+ * @brief Determines whether given cache mode has write-back semantics, i.e. it
+ * allows for writes to be serviced in cache and lazily propagated to core.
+ *
+ * @param[in] mode input cache mode
+ */
+static inline bool ocf_mngt_cache_mode_has_lazy_write(ocf_cache_mode_t mode)
+{
+	return mode == ocf_cache_mode_wb || mode == ocf_cache_mode_wo;
+}
+
 /**
  * @brief Set cache mode in given cache
  *
diff --git a/src/engine/cache_engine.h b/src/engine/cache_engine.h
index d31fe44..17c36f7 100644
--- a/src/engine/cache_engine.h
+++ b/src/engine/cache_engine.h
@@ -59,6 +59,13 @@ static inline bool ocf_cache_mode_is_valid(ocf_cache_mode_t mode)
 	return mode >= ocf_cache_mode_wt && mode < ocf_cache_mode_max;
 }
 
+static inline bool ocf_req_cache_mode_has_lazy_write(ocf_req_cache_mode_t mode)
+{
+	return ocf_cache_mode_is_valid((ocf_cache_mode_t)mode) &&
+			ocf_mngt_cache_mode_has_lazy_write(
+					(ocf_cache_mode_t)mode);
+}
+
 void ocf_seq_cutoff_update(ocf_core_t core, struct ocf_request *req);
 
 bool ocf_fallback_pt_is_on(ocf_cache_t cache);
diff --git a/src/mngt/ocf_mngt_cache.c b/src/mngt/ocf_mngt_cache.c
index d95668d..fca2ab8 100644
--- a/src/mngt/ocf_mngt_cache.c
+++ b/src/mngt/ocf_mngt_cache.c
@@ -2147,8 +2147,10 @@ static int _cache_mngt_set_cache_mode(ocf_cache_t cache, ocf_cache_mode_t mode)
 
 	cache->conf_meta->cache_mode = mode;
 
-	if (mode_old == ocf_cache_mode_wb)
+	if (ocf_mngt_cache_mode_has_lazy_write(mode_old) &&
+			!ocf_mngt_cache_mode_has_lazy_write(mode)) {
 		_cache_mngt_update_initial_dirty_clines(cache);
+	}
 
 	ocf_cache_log(cache, log_info, "Changing cache mode from '%s' to '%s' "
 			"successful\n", ocf_get_io_iface_name(mode_old),
diff --git a/src/ocf_core.c b/src/ocf_core.c
index f6d66da..33a6628 100644
--- a/src/ocf_core.c
+++ b/src/ocf_core.c
@@ -251,7 +251,9 @@ void ocf_core_submit_io_mode(struct ocf_io *io, ocf_cache_mode_t cache_mode)
 
 	if (cache_mode == ocf_cache_mode_none)
 		req_cache_mode = ocf_get_effective_cache_mode(cache, core, io);
-	if (req_cache_mode == ocf_req_cache_mode_wb &&
+
+	if (io->dir == OCF_WRITE &&
+			ocf_req_cache_mode_has_lazy_write(req_cache_mode) &&
 			ocf_io_set_dirty(cache, core_io)) {
 		req_cache_mode = ocf_req_cache_mode_wt;
 	}
@@ -319,7 +321,9 @@ int ocf_core_submit_io_fast(struct ocf_io *io)
 	}
 
 	req_cache_mode = ocf_get_effective_cache_mode(cache, core, io);
-	if (req_cache_mode == ocf_req_cache_mode_wb &&
+
+	if (io->dir == OCF_WRITE &&
+			ocf_req_cache_mode_has_lazy_write(req_cache_mode) &&
 			ocf_io_set_dirty(cache, core_io)) {
 		req_cache_mode = ocf_req_cache_mode_wt;
 	}
@@ -328,6 +332,7 @@ int ocf_core_submit_io_fast(struct ocf_io *io)
 	case ocf_req_cache_mode_pt:
 		return -OCF_ERR_IO;
 	case ocf_req_cache_mode_wb:
+	case ocf_req_cache_mode_wo:
 		req_cache_mode = ocf_req_cache_mode_fast;
 		break;
 	default: