powerpc/spufs: Use simple_write_to_buffer

Simplify several write fileoperations for spufs by using
simple_write_to_buffer().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index 02f7b11..3c7c3f8 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -219,24 +219,17 @@ spufs_mem_write(struct file *file, const char __user *buffer,
        loff_t pos = *ppos;
        int ret;
 
-       if (pos < 0)
-               return -EINVAL;
        if (pos > LS_SIZE)
                return -EFBIG;
-       if (size > LS_SIZE - pos)
-               size = LS_SIZE - pos;
 
        ret = spu_acquire(ctx);
        if (ret)
                return ret;
 
        local_store = ctx->ops->get_ls(ctx);
-       ret = copy_from_user(local_store + pos, buffer, size);
+       size = simple_write_to_buffer(local_store, LS_SIZE, ppos, buffer, size);
        spu_release(ctx);
 
-       if (ret)
-               return -EFAULT;
-       *ppos = pos + size;
        return size;
 }
 
@@ -574,18 +567,15 @@ spufs_regs_write(struct file *file, const char __user *buffer,
        if (*pos >= sizeof(lscsa->gprs))
                return -EFBIG;
 
-       size = min_t(ssize_t, sizeof(lscsa->gprs) - *pos, size);
-       *pos += size;
-
        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
 
-       ret = copy_from_user((char *)lscsa->gprs + *pos - size,
-                            buffer, size) ? -EFAULT : size;
+       size = simple_write_to_buffer(lscsa->gprs, sizeof(lscsa->gprs), pos,
+                                       buffer, size);
 
        spu_release_saved(ctx);
-       return ret;
+       return size;
 }
 
 static const struct file_operations spufs_regs_fops = {
@@ -630,18 +620,15 @@ spufs_fpcr_write(struct file *file, const char __user * buffer,
        if (*pos >= sizeof(lscsa->fpcr))
                return -EFBIG;
 
-       size = min_t(ssize_t, sizeof(lscsa->fpcr) - *pos, size);
-
        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
 
-       *pos += size;
-       ret = copy_from_user((char *)&lscsa->fpcr + *pos - size,
-                            buffer, size) ? -EFAULT : size;
+       size = simple_write_to_buffer(&lscsa->fpcr, sizeof(lscsa->fpcr), pos,
+                                       buffer, size);
 
        spu_release_saved(ctx);
-       return ret;
+       return size;
 }
 
 static const struct file_operations spufs_fpcr_fops = {