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Date: Fri, 22 Sep 2017 15:36:51 +0300
From: Adrian Hunter <adrian.hunter@...el.com>
To: Ulf Hansson <ulf.hansson@...aro.org>
Cc: linux-mmc <linux-mmc@...r.kernel.org>,
linux-block <linux-block@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
Bough Chen <haibo.chen@....com>,
Alex Lemberg <alex.lemberg@...disk.com>,
Mateusz Nowak <mateusz.nowak@...el.com>,
Yuliy Izrailov <Yuliy.Izrailov@...disk.com>,
Jaehoon Chung <jh80.chung@...sung.com>,
Dong Aisheng <dongas86@...il.com>,
Das Asutosh <asutoshd@...eaurora.org>,
Zhangfei Gao <zhangfei.gao@...il.com>,
Sahitya Tummala <stummala@...eaurora.org>,
Harjani Ritesh <riteshh@...eaurora.org>,
Venu Byravarasu <vbyravarasu@...dia.com>,
Linus Walleij <linus.walleij@...aro.org>,
Shawn Lin <shawn.lin@...k-chips.com>,
Christoph Hellwig <hch@....de>
Subject: [PATCH V9 02/15] 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@...el.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(-)
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index ab9c780df750..41e7124b8679 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -1989,7 +1989,7 @@ 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) {
@@ -2052,7 +2052,7 @@ 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 66c9cf49ad2f..b997cf92ce6c 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -832,9 +832,36 @@ 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
@@ -842,8 +869,10 @@ unsigned int mmc_align_data_size(struct mmc_card *card, unsigned int sz)
* 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;
@@ -856,7 +885,7 @@ 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();
@@ -865,7 +894,7 @@ 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;
@@ -900,6 +929,7 @@ 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);
@@ -913,10 +943,10 @@ void mmc_release_host(struct mmc_host *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);
@@ -924,9 +954,13 @@ void mmc_get_card(struct mmc_card *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 ca861091a776..94675f88f704 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -128,10 +128,11 @@ int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
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 @@ int mmc_set_blockcount(struct mmc_card *card, unsigned int blockcount,
*/
static inline void mmc_claim_host(struct mmc_host *host)
{
- __mmc_claim_host(host, NULL);
+ __mmc_claim_host(host, NULL, NULL);
}
#endif
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index a7eb623f8daa..3927157207b9 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1909,14 +1909,14 @@ 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 4fd1620b732d..2036b2b4835c 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1056,14 +1056,14 @@ 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);
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 9a43763a68ad..443f7a8cdfe5 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -255,6 +255,10 @@ 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;
@@ -388,8 +392,9 @@ 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 */
--
1.9.1
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