[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 7fb9a6dc4f18..a528020baa18 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);
 }