From: Adrian Hunter <adrian.hunter@intel.com>
Date: Fri, 22 Sep 2017 15:36:51 +0300
Subject: mmc: core: Introduce host claiming by context
Git-commit: 6c0cedd1ef9527ef13e66875746570e76a3188a7
Patch-mainline: v4.15-rc1
References: FATE#324519
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>
Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.com>
---
drivers/mmc/core/block.c | 4 +--
drivers/mmc/core/core.c | 48 +++++++++++++++++++++++++++++++++++++-------
drivers/mmc/core/core.h | 9 ++++----
drivers/mmc/core/mmc.c | 4 +--
drivers/mmc/core/sd.c | 4 +--
drivers/mmc/core/sdio_irq.c | 3 +-
include/linux/mmc/host.h | 7 +++++-
7 files changed, 60 insertions(+), 19 deletions(-)
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -1949,7 +1949,7 @@ void mmc_blk_issue_rq(struct mmc_queue *
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) {
@@ -2012,7 +2012,7 @@ void mmc_blk_issue_rq(struct mmc_queue *
out:
if (!mq->qcnt)
- mmc_put_card(card);
+ mmc_put_card(card, NULL);
}
static inline int mmc_blk_readonly(struct mmc_card *card)
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -900,9 +900,36 @@ unsigned int mmc_align_data_size(struct
}
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
@@ -910,8 +937,10 @@ 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;
@@ -924,7 +953,7 @@ int __mmc_claim_host(struct mmc_host *ho
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();
@@ -933,7 +962,7 @@ int __mmc_claim_host(struct mmc_host *ho
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;
@@ -968,6 +997,7 @@ void mmc_release_host(struct mmc_host *h
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);
@@ -981,10 +1011,10 @@ 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);
@@ -992,9 +1022,13 @@ 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);
}
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -122,10 +122,11 @@ int mmc_set_blocklen(struct mmc_card *ca
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
@@ -135,7 +136,7 @@ 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);
}
#endif
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1917,14 +1917,14 @@ static void mmc_detect(struct mmc_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);
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1070,14 +1070,14 @@ static void mmc_sd_detect(struct mmc_hos
{
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);
--- a/drivers/mmc/core/sdio_irq.c
+++ b/drivers/mmc/core/sdio_irq.c
@@ -137,7 +137,8 @@ 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);
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -253,6 +253,10 @@ struct mmc_supply {
struct regulator *vqmmc; /* Optional Vccq supply */
};
+struct mmc_ctx {
+ struct task_struct *task;
+};
+
struct mmc_host {
struct device *parent;
struct device class_dev;
@@ -389,8 +393,9 @@ struct mmc_host {
struct mmc_card *card; /* device attached to this host */
wait_queue_head_t wq;
- struct task_struct *claimer; /* task that has host claimed */
+ struct mmc_ctx *claimer; /* context that has host claimed */
int claim_cnt; /* "claim" nesting count */
+ struct mmc_ctx default_ctx; /* default context */
struct delayed_work detect;
int detect_change; /* card detect flag */