[POWERPC] spufs: Fix bitrot of the SPU mmap facility

It looks like we've had some serious bitrot there mostly due to tracking
of address_space's of mmap'ed files getting out of sync with the actual
mmap code. The mfc, mss and psmap were not tracked properly and thus
not invalidated on context switches (oops !)

I also removed the various file->f_mapping = inode->i_mapping;
assignments that were done in the other open() routines since that
is already done for us by __dentry_open.

One improvement we might want to do later is to assign the various
ctx-> fields at mmap time instead of file open/close time so that we
don't call unmap_mapping_range() on thing that have not been mmap'ed

Finally, I added some smp_wmb's after assigning the ctx-> fields to make
sure they are visible to other CPUs. I don't think this is really
necessary as I suspect locking in the fs layer will make that happen
anyway but better safe than sorry.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 12 insertions, 4 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index 7fb9a6dc4f1..a528020baa1 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -45,8 +45,8 @@ spufs_mem_open(struct inode *inode, struct file *file)
 	struct spufs_inode_info *i = SPUFS_I(inode);
 	struct spu_context *ctx = i->i_ctx;
 	file->private_data = ctx;
-	file->f_mapping = inode->i_mapping;
 	ctx->local_store = inode->i_mapping;
+	smp_wmb();
 	return 0;
 }
 
@@ -232,8 +232,8 @@ static int spufs_cntl_open(struct inode *inode, struct file *file)
 	struct spu_context *ctx = i->i_ctx;
 
 	file->private_data = ctx;
-	file->f_mapping = inode->i_mapping;
 	ctx->cntl = inode->i_mapping;
+	smp_wmb();
 	return simple_attr_open(inode, file, spufs_cntl_get,
 					spufs_cntl_set, "0x%08lx");
 }
@@ -717,8 +717,8 @@ static int spufs_signal1_open(struct inode *inode, struct file *file)
 	struct spufs_inode_info *i = SPUFS_I(inode);
 	struct spu_context *ctx = i->i_ctx;
 	file->private_data = ctx;
-	file->f_mapping = inode->i_mapping;
 	ctx->signal1 = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -824,8 +824,8 @@ static int spufs_signal2_open(struct inode *inode, struct file *file)
 	struct spufs_inode_info *i = SPUFS_I(inode);
 	struct spu_context *ctx = i->i_ctx;
 	file->private_data = ctx;
-	file->f_mapping = inode->i_mapping;
 	ctx->signal2 = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -1021,8 +1021,11 @@ static int spufs_mss_mmap(struct file *file, struct vm_area_struct *vma)
 static int spufs_mss_open(struct inode *inode, struct file *file)
 {
 	struct spufs_inode_info *i = SPUFS_I(inode);
+	struct spu_context *ctx = i->i_ctx;
 
 	file->private_data = i->i_ctx;
+	ctx->mss = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -1060,8 +1063,11 @@ static int spufs_psmap_mmap(struct file *file, struct vm_area_struct *vma)
 static int spufs_psmap_open(struct inode *inode, struct file *file)
 {
 	struct spufs_inode_info *i = SPUFS_I(inode);
+	struct spu_context *ctx = i->i_ctx;
 
 	file->private_data = i->i_ctx;
+	ctx->psmap = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -1114,6 +1120,8 @@ static int spufs_mfc_open(struct inode *inode, struct file *file)
 		return -EBUSY;
 
 	file->private_data = ctx;
+	ctx->mfc = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }