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authorAdrian Hunter <adrian.hunter@nokia.com>2009-09-22 16:44:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-23 07:39:33 -0700
commit319a3f1429c91147058ac26c5f5bac8ec1730bc6 (patch)
tree4a39ff034f7e9b57b903997f818eee5304657991
parent8ea926b22e2d13238e4d65d8f61c48fe424e6f4f (diff)
mmc: allow host claim / release nesting
This change allows the MMC host to be claimed in situations where the host may or may not have already been claimed. Also 'mmc_try_claim_host()' is now exported. Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com> Acked-by: Matt Fleming <matt@console-pimps.org> Cc: Ian Molton <ian@mnementh.co.uk> Cc: "Roberto A. Foglietta" <roberto.foglietta@gmail.com> Cc: Jarkko Lavinen <jarkko.lavinen@nokia.com> Cc: Denis Karpov <ext-denis.2.karpov@nokia.com> Cc: Pierre Ossman <pierre@ossman.eu> Cc: Philip Langdale <philipl@overt.org> Cc: "Madhusudhan" <madhu.cr@ti.com> Cc: <linux-mmc@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/mmc/core/core.c34
-rw-r--r--include/linux/mmc/core.h1
-rw-r--r--include/linux/mmc/host.h2
3 files changed, 28 insertions, 9 deletions
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index fb24a096dba..02f2b1871a3 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -461,16 +461,18 @@ 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)
+ if (stop || !host->claimed || host->claimer == current)
break;
spin_unlock_irqrestore(&host->lock, flags);
schedule();
spin_lock_irqsave(&host->lock, flags);
}
set_current_state(TASK_RUNNING);
- if (!stop)
+ if (!stop) {
host->claimed = 1;
- else
+ host->claimer = current;
+ host->claim_cnt += 1;
+ } else
wake_up(&host->wq);
spin_unlock_irqrestore(&host->lock, flags);
remove_wait_queue(&host->wq, &wait);
@@ -481,29 +483,43 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)
EXPORT_SYMBOL(__mmc_claim_host);
-static int mmc_try_claim_host(struct mmc_host *host)
+/**
+ * mmc_try_claim_host - try exclusively to claim a host
+ * @host: mmc host to claim
+ *
+ * Returns %1 if the host is claimed, %0 otherwise.
+ */
+int mmc_try_claim_host(struct mmc_host *host)
{
int claimed_host = 0;
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
- if (!host->claimed) {
+ if (!host->claimed || host->claimer == current) {
host->claimed = 1;
+ host->claimer = current;
+ host->claim_cnt += 1;
claimed_host = 1;
}
spin_unlock_irqrestore(&host->lock, flags);
return claimed_host;
}
+EXPORT_SYMBOL(mmc_try_claim_host);
static void mmc_do_release_host(struct mmc_host *host)
{
unsigned long flags;
spin_lock_irqsave(&host->lock, flags);
- host->claimed = 0;
- spin_unlock_irqrestore(&host->lock, flags);
-
- wake_up(&host->wq);
+ if (--host->claim_cnt) {
+ /* Release for nested claim */
+ spin_unlock_irqrestore(&host->lock, flags);
+ } else {
+ host->claimed = 0;
+ host->claimer = NULL;
+ spin_unlock_irqrestore(&host->lock, flags);
+ wake_up(&host->wq);
+ }
}
void mmc_host_deeper_disable(struct work_struct *work)
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 7ac8b500d55..e4898e9eeb5 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -139,6 +139,7 @@ extern unsigned int mmc_align_data_size(struct mmc_card *, unsigned int);
extern int __mmc_claim_host(struct mmc_host *host, atomic_t *abort);
extern void mmc_release_host(struct mmc_host *host);
+extern int mmc_try_claim_host(struct mmc_host *host);
/**
* mmc_claim_host - exclusively claim a host
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 338a9b3d51e..631a2fea526 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -182,6 +182,8 @@ 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 */
+ int claim_cnt; /* "claim" nesting count */
struct delayed_work detect;