[PATCH V8 08/14] mmc: core: Add parameter use_blk_mq

[Adrian Hunter]

Until mmc has blk-mq support fully implemented and tested, add a
parameter use_blk_mq, default to false unless config option MMC_MQ_DEFAULT
is selected.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
 drivers/mmc/Kconfig      | 11 +++++++++++
 drivers/mmc/core/core.c  |  7 +++++++
 drivers/mmc/core/core.h  |  2 ++
 drivers/mmc/core/host.c  |  2 ++
 drivers/mmc/core/host.h  |  4 ++++
 include/linux/mmc/host.h |  1 +
 6 files changed, 27 insertions(+)

diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index ec21388311db..98202934bd29 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -12,6 +12,17 @@ menuconfig MMC
 	  If you want MMC/SD/SDIO support, you should say Y here and
 	  also to your specific host controller driver.
 
+config MMC_MQ_DEFAULT
+	bool "MMC: use blk-mq I/O path by default"
+	depends on MMC && BLOCK
+	---help---
+	  This option enables the new blk-mq based I/O path for MMC block
+	  devices by default.  With the option the mmc_core.use_blk_mq
+	  module/boot option defaults to Y, without it to N, but it can
+	  still be overridden either way.
+
+	  If unsure say N.
+
 if MMC
 
 source "drivers/mmc/core/Kconfig"
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index ef2d8aa1e7d2..3638ed4f0f9e 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -66,6 +66,13 @@
 bool use_spi_crc = 1;
 module_param(use_spi_crc, bool, 0);
 
+#ifdef CONFIG_MMC_MQ_DEFAULT
+bool mmc_use_blk_mq = true;
+#else
+bool mmc_use_blk_mq = false;
+#endif
+module_param_named(use_blk_mq, mmc_use_blk_mq, bool, S_IWUSR | S_IRUGO);
+
 static int mmc_schedule_delayed_work(struct delayed_work *work,
 				     unsigned long delay)
 {
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index e941342ed450..535539a9e7eb 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -35,6 +35,8 @@ struct mmc_bus_ops {
 	int (*reset)(struct mmc_host *);
 };
 
+extern bool mmc_use_blk_mq;
+
 void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
 void mmc_detach_bus(struct mmc_host *host);
 
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index ad88deb2e8f3..b624dbb6cd15 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -398,6 +398,8 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 	host->max_blk_size = 512;
 	host->max_blk_count = PAGE_SIZE / 512;
 
+	host->use_blk_mq = mmc_use_blk_mq;
+
 	return host;
 }
 
diff --git a/drivers/mmc/core/host.h b/drivers/mmc/core/host.h
index 77d6f60d1bf9..170fe5947087 100644
--- a/drivers/mmc/core/host.h
+++ b/drivers/mmc/core/host.h
@@ -69,6 +69,10 @@ static inline bool mmc_card_hs400es(struct mmc_card *card)
 	return card->host->ios.enhanced_strobe;
 }
 
+static inline bool mmc_host_use_blk_mq(struct mmc_host *host)
+{
+	return host->use_blk_mq;
+}
 
 #endif
 
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 54b0463443bd..5d1bd10991f7 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -378,6 +378,7 @@ struct mmc_host {
 	unsigned int		doing_retune:1;	/* re-tuning in progress */
 	unsigned int		retune_now:1;	/* do re-tuning at next req */
 	unsigned int		retune_paused:1; /* re-tuning is temporarily disabled */
+	unsigned int		use_blk_mq:1;	/* use blk-mq */
 
 	int			rescan_disable;	/* disable card detection */
 	int			rescan_entered;	/* used with nonremovable devices */
-- 
1.9.1