[POWERPC] spufs: block fault handlers in spu_acquire_runnable

This change disables the logic that faults-in spu contexts under the
covers from the page fault handler.  When a fault requires a runnable
context, the handler will block until the context is scheduled by
other means.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c
index 9cb081c26e7120f5ca84c8ecb2e7ff7ae7814df4..6fa24d38706ea7d96b43f8159236c0c874689676 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/context.c
+++ b/arch/powerpc/platforms/cell/spufs/context.c
@@ -52,6 +52,7 @@ struct spu_context *alloc_spu_context(struct spu_gang *gang)
        init_waitqueue_head(&ctx->wbox_wq);
        init_waitqueue_head(&ctx->stop_wq);
        init_waitqueue_head(&ctx->mfc_wq);
+       init_waitqueue_head(&ctx->run_wq);
        ctx->state = SPU_STATE_SAVED;
        ctx->ops = &spu_backing_ops;
        ctx->owner = get_task_mm(current);

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index d9e56a503795246ee9f4848a23224a27635a2577..714972621220abdb866874f0af3dd81acf7abdde 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -236,21 +236,31 @@ static unsigned long spufs_ps_nopfn(struct vm_area_struct *vma,
 {
        struct spu_context *ctx = vma->vm_file->private_data;
        unsigned long area, offset = address - vma->vm_start;
-       int ret;
 
        offset += vma->vm_pgoff << PAGE_SHIFT;
        if (offset >= ps_size)
                return NOPFN_SIGBUS;
 
-       /* error here usually means a signal.. we might want to test
-        * the error code more precisely though
+       /*
+        * We have to wait for context to be loaded before we have
+        * pages to hand out to the user, but we don't want to wait
+        * with the mmap_sem held.
+        * It is possible to drop the mmap_sem here, but then we need
+        * to return NOPFN_REFAULT because the mappings may have
+        * hanged.
         */
-       ret = spu_acquire_runnable(ctx, 0);
-       if (ret)
-               return NOPFN_REFAULT;
+       spu_acquire(ctx);
+       if (ctx->state == SPU_STATE_SAVED) {
+               up_read(&current->mm->mmap_sem);
+               spufs_wait(ctx->run_wq, ctx->state == SPU_STATE_RUNNABLE);
+               down_read(&current->mm->mmap_sem);
+               goto out;
+       }
 
        area = ctx->spu->problem_phys + ps_offs;
        vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT);
+
+out:
        spu_release(ctx);
 
        return NOPFN_REFAULT;
@@ -1505,7 +1515,8 @@ static ssize_t spufs_mfc_write(struct file *file, const char __user *buffer,
        if (ret)
                goto out;
 
-       ret = spu_acquire_runnable(ctx, 0);
+       spu_acquire(ctx);
+       ret = spufs_wait(ctx->run_wq, ctx->state == SPU_STATE_RUNNABLE);
        if (ret)
                goto out;
 

diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index ee80de07c0bcb3c44d0a11241f4bfcbc2c1376d1..52215aa2f3c685fe964a108b852c69eaad42def8 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -682,6 +682,7 @@ int spu_activate(struct spu_context *ctx, unsigned long flags)
                        spu_bind_context(spu, ctx);
                        cbe_spu_info[node].nr_active++;
                        mutex_unlock(&cbe_spu_info[node].list_mutex);
+                       wake_up_all(&ctx->run_wq);
                        return 0;
                }
 

diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index cce50f317c784fa3eed8ec7d7887191d3504bc20..fcab1504f11719d114ea750481934a69c91cbb42 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -71,6 +71,7 @@ struct spu_context {
        wait_queue_head_t wbox_wq;
        wait_queue_head_t stop_wq;
        wait_queue_head_t mfc_wq;
+       wait_queue_head_t run_wq;
        struct fasync_struct *ibox_fasync;
        struct fasync_struct *wbox_fasync;
        struct fasync_struct *mfc_fasync;