[POWERPC] spufs: state_mutex cleanup

Various cleanups in code surrounding the state semaphore:

 - inline spu_acquire/spu_release
 - cleanup spu_acquire_* and add kerneldoc comments to these functions
 - remove spu_release_exclusive and replace it with spu_release

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c
index c9aab9b..f2630dc 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/context.c
+++ b/arch/powerpc/platforms/cell/spufs/context.c
@@ -96,16 +96,6 @@ void spu_forget(struct spu_context *ctx)
        spu_release(ctx);
 }
 
-void spu_acquire(struct spu_context *ctx)
-{
-       mutex_lock(&ctx->state_mutex);
-}
-
-void spu_release(struct spu_context *ctx)
-{
-       mutex_unlock(&ctx->state_mutex);
-}
-
 void spu_unmap_mappings(struct spu_context *ctx)
 {
        if (ctx->local_store)
@@ -124,66 +114,85 @@ void spu_unmap_mappings(struct spu_context *ctx)
                unmap_mapping_range(ctx->psmap, 0, 0x20000, 1);
 }
 
+/**
+ * spu_acquire_exclusive - lock spu contex and protect against userspace access
+ * @ctx:       spu contex to lock
+ *
+ * Note:
+ *     Returns 0 and with the context locked on success
+ *     Returns negative error and with the context _unlocked_ on failure.
+ */
 int spu_acquire_exclusive(struct spu_context *ctx)
 {
-       int ret = 0;
+       int ret = -EINVAL;
 
-       mutex_lock(&ctx->state_mutex);
-       /* ctx is about to be freed, can't acquire any more */
-       if (!ctx->owner) {
-               ret = -EINVAL;
-               goto out;
-       }
+       spu_acquire(ctx);
+       /*
+        * Context is about to be freed, so we can't acquire it anymore.
+        */
+       if (!ctx->owner)
+               goto out_unlock;
 
        if (ctx->state == SPU_STATE_SAVED) {
                ret = spu_activate(ctx, 0);
                if (ret)
-                       goto out;
+                       goto out_unlock;
        } else {
-               /* We need to exclude userspace access to the context. */
+               /*
+                * We need to exclude userspace access to the context.
+                *
+                * To protect against memory access we invalidate all ptes
+                * and make sure the pagefault handlers block on the mutex.
+                */
                spu_unmap_mappings(ctx);
        }
 
-out:
-       if (ret)
-               mutex_unlock(&ctx->state_mutex);
+       return 0;
+
+ out_unlock:
+       spu_release(ctx);
        return ret;
 }
 
+/**
+ * spu_acquire_runnable - lock spu contex and make sure it is in runnable state
+ * @ctx:       spu contex to lock
+ *
+ * Note:
+ *     Returns 0 and with the context locked on success
+ *     Returns negative error and with the context _unlocked_ on failure.
+ */
 int spu_acquire_runnable(struct spu_context *ctx)
 {
-       int ret = 0;
-
-       mutex_lock(&ctx->state_mutex);
-       if (ctx->state == SPU_STATE_RUNNABLE) {
-               ctx->spu->prio = current->prio;
-               return 0;
-       }
-
-       /* ctx is about to be freed, can't acquire any more */
-       if (!ctx->owner) {
-               ret = -EINVAL;
-               goto out;
-       }
+       int ret = -EINVAL;
 
+       spu_acquire(ctx);
        if (ctx->state == SPU_STATE_SAVED) {
+               /*
+                * Context is about to be freed, so we can't acquire it anymore.
+                */
+               if (!ctx->owner)
+                       goto out_unlock;
                ret = spu_activate(ctx, 0);
                if (ret)
-                       goto out;
-       }
+                       goto out_unlock;
+       } else
+               ctx->spu->prio = current->prio;
 
-       /* On success, we return holding the lock */
-       return ret;
-out:
-       /* Release here, to simplify calling code. */
-       mutex_unlock(&ctx->state_mutex);
+       return 0;
 
+ out_unlock:
+       spu_release(ctx);
        return ret;
 }
 
+/**
+ * spu_acquire_saved - lock spu contex and make sure it is in saved state
+ * @ctx:       spu contex to lock
+ */
 void spu_acquire_saved(struct spu_context *ctx)
 {
-       mutex_lock(&ctx->state_mutex);
-       if (ctx->state == SPU_STATE_RUNNABLE)
+       spu_acquire(ctx);
+       if (ctx->state != SPU_STATE_SAVED)
                spu_deactivate(ctx);
 }

diff --git a/arch/powerpc/platforms/cell/spufs/run.c b/arch/powerpc/platforms/cell/spufs/run.c
index 51b78da..e164731 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/run.c
+++ b/arch/powerpc/platforms/cell/spufs/run.c
@@ -133,7 +133,7 @@ out_drop_priv:
        spu_mfc_sr1_set(ctx->spu, sr1);
 
 out_unlock:
-       spu_release_exclusive(ctx);
+       spu_release(ctx);
 out:
        return ret;
 }

diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index de2401a..fa07ec2 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -158,6 +158,16 @@ void spu_gang_remove_ctx(struct spu_gang *gang, struct spu_context *ctx);
 void spu_gang_add_ctx(struct spu_gang *gang, struct spu_context *ctx);
 
 /* context management */
+static inline void spu_acquire(struct spu_context *ctx)
+{
+       mutex_lock(&ctx->state_mutex);
+}
+
+static inline void spu_release(struct spu_context *ctx)
+{
+       mutex_unlock(&ctx->state_mutex);
+}
+
 struct spu_context * alloc_spu_context(struct spu_gang *gang);
 void destroy_spu_context(struct kref *kref);
 struct spu_context * get_spu_context(struct spu_context *ctx);
@@ -165,17 +175,9 @@ int put_spu_context(struct spu_context *ctx);
 void spu_unmap_mappings(struct spu_context *ctx);
 
 void spu_forget(struct spu_context *ctx);
-void spu_acquire(struct spu_context *ctx);
-void spu_release(struct spu_context *ctx);
 int spu_acquire_runnable(struct spu_context *ctx);
 void spu_acquire_saved(struct spu_context *ctx);
 int spu_acquire_exclusive(struct spu_context *ctx);
-
-static inline void spu_release_exclusive(struct spu_context *ctx)
-{
-       mutex_unlock(&ctx->state_mutex);
-}
-
 int spu_activate(struct spu_context *ctx, u64 flags);
 void spu_deactivate(struct spu_context *ctx);
 void spu_yield(struct spu_context *ctx);