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Commit 650f8b02 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Arnd Bergmann
Browse files

[POWERPC] spufs: simplify state_mutex 



The r/w semaphore to lock the spus was overkill and can be replaced
with a mutex to make it faster, simpler and easier to debug.  It also
helps to allow making most spufs interruptible in future patches.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarArnd Bergmann <arnd.bergmann@de.ibm.com>
parent 202557d2

arch/powerpc/platforms/cell/spufs/context.c

+10 −23
Original line number Diff line number Diff line
@@ -42,7 +42,7 @@ struct spu_context *alloc_spu_context(struct spu_gang *gang) 
	}

	spin_lock_init(&ctx->mmio_lock);

	kref_init(&ctx->kref);

	init_rwsem(&ctx->state_sema);

	mutex_init(&ctx->state_mutex);

	init_MUTEX(&ctx->run_sema);

	init_waitqueue_head(&ctx->ibox_wq);

	init_waitqueue_head(&ctx->wbox_wq);
@@ -65,9 +65,9 @@ void destroy_spu_context(struct kref *kref) 
{

	struct spu_context *ctx;

	ctx = container_of(kref, struct spu_context, kref);

	down_write(&ctx->state_sema);

	mutex_lock(&ctx->state_mutex);

	spu_deactivate(ctx);

	up_write(&ctx->state_sema);

	mutex_unlock(&ctx->state_mutex);

	spu_fini_csa(&ctx->csa);

	if (ctx->gang)

		spu_gang_remove_ctx(ctx->gang, ctx);
@@ -98,12 +98,12 @@ void spu_forget(struct spu_context *ctx) 


void spu_acquire(struct spu_context *ctx)

{

	down_read(&ctx->state_sema);

	mutex_lock(&ctx->state_mutex);

}



void spu_release(struct spu_context *ctx)

{

	up_read(&ctx->state_sema);

	mutex_unlock(&ctx->state_mutex);

}



void spu_unmap_mappings(struct spu_context *ctx)
@@ -128,7 +128,7 @@ int spu_acquire_exclusive(struct spu_context *ctx) 
{

	int ret = 0;



	down_write(&ctx->state_sema);

	mutex_lock(&ctx->state_mutex);

	/* ctx is about to be freed, can't acquire any more */

	if (!ctx->owner) {

		ret = -EINVAL;
@@ -146,7 +146,7 @@ int spu_acquire_exclusive(struct spu_context *ctx) 


out:

	if (ret)

		up_write(&ctx->state_sema);

		mutex_unlock(&ctx->state_mutex);

	return ret;

}
@@ -154,14 +154,12 @@ int spu_acquire_runnable(struct spu_context *ctx) 
{

	int ret = 0;



	down_read(&ctx->state_sema);

	mutex_lock(&ctx->state_mutex);

	if (ctx->state == SPU_STATE_RUNNABLE) {

		ctx->spu->prio = current->prio;

		return 0;

	}

	up_read(&ctx->state_sema);



	down_write(&ctx->state_sema);

	/* ctx is about to be freed, can't acquire any more */

	if (!ctx->owner) {

		ret = -EINVAL;
@@ -174,29 +172,18 @@ int spu_acquire_runnable(struct spu_context *ctx) 
			goto out;

	}



	downgrade_write(&ctx->state_sema);

	/* On success, we return holding the lock */



	return ret;

out:

	/* Release here, to simplify calling code. */

	up_write(&ctx->state_sema);

	mutex_unlock(&ctx->state_mutex);



	return ret;

}



void spu_acquire_saved(struct spu_context *ctx)

{

	down_read(&ctx->state_sema);



	if (ctx->state == SPU_STATE_SAVED)

		return;



	up_read(&ctx->state_sema);

	down_write(&ctx->state_sema);



	mutex_lock(&ctx->state_mutex);

	if (ctx->state == SPU_STATE_RUNNABLE)

		spu_deactivate(ctx);



	downgrade_write(&ctx->state_sema);

}

arch/powerpc/platforms/cell/spufs/sched.c

+4 −4
Original line number Diff line number Diff line
@@ -233,11 +233,11 @@ static void spu_prio_wait(struct spu_context *ctx, u64 flags) 
	spu_add_wq(wq, &wait, prio);



	if (!signal_pending(current)) {

		up_write(&ctx->state_sema);

		mutex_unlock(&ctx->state_mutex);

		pr_debug("%s: pid=%d prio=%d\n", __FUNCTION__,

			 current->pid, current->prio);

		schedule();

		down_write(&ctx->state_sema);

		mutex_lock(&ctx->state_mutex);

	}



	spu_del_wq(wq, &wait, prio);
@@ -334,7 +334,7 @@ void spu_yield(struct spu_context *ctx) 
	struct spu *spu;

	int need_yield = 0;



	if (down_write_trylock(&ctx->state_sema)) {

	if (mutex_trylock(&ctx->state_mutex)) {

		if ((spu = ctx->spu) != NULL) {

			int best = sched_find_first_bit(spu_prio->bitmap);

			if (best < MAX_PRIO) {
@@ -346,7 +346,7 @@ void spu_yield(struct spu_context *ctx) 
				spu->prio = MAX_PRIO;

			}

		}

		up_write(&ctx->state_sema);

		mutex_unlock(&ctx->state_mutex);

	}

	if (unlikely(need_yield))

		yield();

arch/powerpc/platforms/cell/spufs/spufs.h

+3 −3
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ 
#define SPUFS_H



#include <linux/kref.h>

#include <linux/rwsem.h>

#include <linux/mutex.h>

#include <linux/spinlock.h>

#include <linux/fs.h>
@@ -53,7 +53,7 @@ struct spu_context { 
	u64 object_id;		   /* user space pointer for oprofile */



	enum { SPU_STATE_RUNNABLE, SPU_STATE_SAVED } state;

	struct rw_semaphore state_sema;

	struct mutex state_mutex;

	struct semaphore run_sema;



	struct mm_struct *owner;
@@ -173,7 +173,7 @@ int spu_acquire_exclusive(struct spu_context *ctx); 


static inline void spu_release_exclusive(struct spu_context *ctx)

{

	up_write(&ctx->state_sema);

	mutex_unlock(&ctx->state_mutex);

}



int spu_activate(struct spu_context *ctx, u64 flags);