mmc: core: Introduce host claiming by context

Currently the host can be claimed by a task.  Change this so that the host
can be claimed by a context that may or may not be a task.  This provides
for the host to be claimed by a block driver queue to support blk-mq, while
maintaining compatibility with the existing use of mmc_claim_host().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
(cherry picked from commit 6c0cedd1ef9527ef13e66875746570e76a3188a7)

Adjust for small imx changes in debugfs

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>

7 files changed, 58 insertions, 22 deletions

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 0ae53d219c5b..0b7c8e14a7b2 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2015,7 +2015,7 @@ void mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 
 	if (req && !mq->qcnt)
 		/* claim host only for the first request */
-		mmc_get_card(card);
+		mmc_get_card(card, NULL);
 
 	ret = mmc_blk_part_switch(card, md->part_type);
 	if (ret) {
@@ -2078,7 +2078,7 @@ void mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 
 out:
 	if (!mq->qcnt)
-		mmc_put_card(card);
+		mmc_put_card(card, NULL);
 }
 
 static inline int mmc_blk_readonly(struct mmc_card *card)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index d14f23b005c0..7b04db81494f 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -985,9 +985,36 @@ unsigned int mmc_align_data_size(struct mmc_card *card, unsigned int sz)
 }
 EXPORT_SYMBOL(mmc_align_data_size);
 
+/*
+ * Allow claiming an already claimed host if the context is the same or there is
+ * no context but the task is the same.
+ */
+static inline bool mmc_ctx_matches(struct mmc_host *host, struct mmc_ctx *ctx,
+				   struct task_struct *task)
+{
+	return host->claimer == ctx ||
+	       (!ctx && task && host->claimer->task == task);
+}
+
+static inline void mmc_ctx_set_claimer(struct mmc_host *host,
+				       struct mmc_ctx *ctx,
+				       struct task_struct *task)
+{
+	if (!host->claimer) {
+		if (ctx)
+			host->claimer = ctx;
+		else
+			host->claimer = &host->default_ctx;
+	}
+	if (task)
+		host->claimer->task = task;
+}
+
 /**
  *	__mmc_claim_host - exclusively claim a host
  *	@host: mmc host to claim
+ *	@ctx: context that claims the host or NULL in which case the default
+ *	context will be used
  *	@abort: whether or not the operation should be aborted
  *
  *	Claim a host for a set of operations.  If @abort is non null and
@@ -995,8 +1022,10 @@ EXPORT_SYMBOL(mmc_align_data_size);
  *	that non-zero value without acquiring the lock.  Returns zero
  *	with the lock held otherwise.
  */
-int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)
+int __mmc_claim_host(struct mmc_host *host, struct mmc_ctx *ctx,
+		     atomic_t *abort)
 {
+	struct task_struct *task = ctx ? NULL : current;
 	DECLARE_WAITQUEUE(wait, current);
 	unsigned long flags;
 	int stop;
@@ -1009,7 +1038,7 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)
 	while (1) {
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		stop = abort ? atomic_read(abort) : 0;
-		if (stop || !host->claimed || host->claimer == current)
+		if (stop || !host->claimed || mmc_ctx_matches(host, ctx, task))
 			break;
 		spin_unlock_irqrestore(&host->lock, flags);
 		schedule();
@@ -1018,7 +1047,7 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)
 	set_current_state(TASK_RUNNING);
 	if (!stop) {
 		host->claimed = 1;
-		host->claimer = current;
+		mmc_ctx_set_claimer(host, ctx, task);
 		host->claim_cnt += 1;
 		if (host->claim_cnt == 1)
 			pm = true;
@@ -1053,6 +1082,7 @@ void mmc_release_host(struct mmc_host *host)
 		spin_unlock_irqrestore(&host->lock, flags);
 	} else {
 		host->claimed = 0;
+		host->claimer->task = NULL;
 		host->claimer = NULL;
 		spin_unlock_irqrestore(&host->lock, flags);
 		wake_up(&host->wq);
@@ -1066,10 +1096,10 @@ EXPORT_SYMBOL(mmc_release_host);
  * This is a helper function, which fetches a runtime pm reference for the
  * card device and also claims the host.
  */
-void mmc_get_card(struct mmc_card *card)
+void mmc_get_card(struct mmc_card *card, struct mmc_ctx *ctx)
 {
 	pm_runtime_get_sync(&card->dev);
-	mmc_claim_host(card->host);
+	__mmc_claim_host(card->host, ctx, NULL);
 }
 EXPORT_SYMBOL(mmc_get_card);
 
@@ -1077,9 +1107,13 @@ EXPORT_SYMBOL(mmc_get_card);
  * This is a helper function, which releases the host and drops the runtime
  * pm reference for the card device.
  */
-void mmc_put_card(struct mmc_card *card)
+void mmc_put_card(struct mmc_card *card, struct mmc_ctx *ctx)
 {
-	mmc_release_host(card->host);
+	struct mmc_host *host = card->host;
+
+	WARN_ON(ctx && host->claimer != ctx);
+
+	mmc_release_host(host);
 	pm_runtime_mark_last_busy(&card->dev);
 	pm_runtime_put_autosuspend(&card->dev);
 }
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 90ce8f2a9343..ba5a8fea0dc2 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -128,10 +128,11 @@ int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);
 int mmc_set_blockcount(struct mmc_card *card, unsigned int blockcount,
 			bool is_rel_write);
 
-int __mmc_claim_host(struct mmc_host *host, atomic_t *abort);
+int __mmc_claim_host(struct mmc_host *host, struct mmc_ctx *ctx,
+		     atomic_t *abort);
 void mmc_release_host(struct mmc_host *host);
-void mmc_get_card(struct mmc_card *card);
-void mmc_put_card(struct mmc_card *card);
+void mmc_get_card(struct mmc_card *card, struct mmc_ctx *ctx);
+void mmc_put_card(struct mmc_card *card, struct mmc_ctx *ctx);
 
 /**
  *	mmc_claim_host - exclusively claim a host
@@ -141,7 +142,7 @@ void mmc_put_card(struct mmc_card *card);
  */
 static inline void mmc_claim_host(struct mmc_host *host)
 {
-	__mmc_claim_host(host, NULL);
+	__mmc_claim_host(host, NULL, NULL);
 }
 
 int mmc_cqe_start_req(struct mmc_host *host, struct mmc_request *mrq);
diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index c97311174d31..83a4e64112fc 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -59,7 +59,7 @@ static int mmc_ios_show(struct seq_file *s, void *data)
 	const char *str;
 
 	if (host->card)
-		mmc_get_card(host->card);
+		mmc_get_card(host->card, NULL);
 
 	seq_printf(s, "clock:\t\t%u Hz\n", ios->clock);
 	if (host->actual_clock)
@@ -198,7 +198,7 @@ static int mmc_ios_show(struct seq_file *s, void *data)
 	seq_printf(s, "driver type:\t%u (%s)\n", ios->drv_type, str);
 
 	if (host->card)
-		mmc_put_card(host->card);
+		mmc_put_card(host->card, NULL);
 
 	return 0;
 }
@@ -220,10 +220,10 @@ static int mmc_clock_opt_get(void *data, u64 *val)
 	struct mmc_host *host = data;
 
 	if (host->card)
-		mmc_get_card(host->card);
+		mmc_get_card(host->card, NULL);
 	*val = host->ios.clock;
 	if (host->card)
-		mmc_put_card(host->card);
+		mmc_put_card(host->card, NULL);
 
 	return 0;
 }
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index a243eba3071a..98819a0f0934 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1946,14 +1946,14 @@ static void mmc_detect(struct mmc_host *host)
 {
 	int err;
 
-	mmc_get_card(host->card);
+	mmc_get_card(host->card, NULL);
 
 	/*
 	 * Just check if our card has been removed.
 	 */
 	err = _mmc_detect_card_removed(host);
 
-	mmc_put_card(host->card);
+	mmc_put_card(host->card, NULL);
 
 	if (err) {
 		mmc_remove(host);
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index cf640239fcdd..50786e784199 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1063,14 +1063,14 @@ static void mmc_sd_detect(struct mmc_host *host)
 {
 	int err;
 
-	mmc_get_card(host->card);
+	mmc_get_card(host->card, NULL);
 
 	/*
 	 * Just check if our card has been removed.
 	 */
 	err = _mmc_detect_card_removed(host);
 
-	mmc_put_card(host->card);
+	mmc_put_card(host->card, NULL);
 
 	if (err) {
 		mmc_sd_remove(host);
diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c
index c771843e4c15..7a2eaf8410a3 100644
--- a/drivers/mmc/core/sdio_irq.c
+++ b/drivers/mmc/core/sdio_irq.c
@@ -155,7 +155,8 @@ static int sdio_irq_thread(void *_host)
 		 * holding of the host lock does not cover too much work
 		 * that doesn't require that lock to be held.
 		 */
-		ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
+		ret = __mmc_claim_host(host, NULL,
+				       &host->sdio_irq_thread_abort);
 		if (ret)
 			break;
 		ret = process_sdio_pending_irqs(host);