[PATCH 2/2] powerpc/spufs: stop using access_ok

[Christophe Leroy]

Le 29/04/2020 à 09:03, Jeremy Kerr a écrit :
> From: Christoph Hellwig <hch at lst.de>
> 
> Just use the proper non __-prefixed get/put_user variants where that is
> not done yet.

But it means you are doing the access_ok() check everytime, which is 
what is to be avoided by doing the access_ok() once then using the 
__-prefixed variant.

Christophe

> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> Signed-off-by: Jeremy Kerr <jk at ozlabs.org>
> ---
>   arch/powerpc/platforms/cell/spufs/file.c | 42 +++++-------------------
>   1 file changed, 8 insertions(+), 34 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
> index b4e1ef650b40..cd7d10f27fad 100644
> --- a/arch/powerpc/platforms/cell/spufs/file.c
> +++ b/arch/powerpc/platforms/cell/spufs/file.c
> @@ -590,17 +590,12 @@ static ssize_t spufs_mbox_read(struct file *file, char __user *buf,
>   			size_t len, loff_t *pos)
>   {
>   	struct spu_context *ctx = file->private_data;
> -	u32 mbox_data, __user *udata;
> +	u32 mbox_data, __user *udata = (void __user *)buf;
>   	ssize_t count;
>   
>   	if (len < 4)
>   		return -EINVAL;
>   
> -	if (!access_ok(buf, len))
> -		return -EFAULT;
> -
> -	udata = (void __user *)buf;
> -
>   	count = spu_acquire(ctx);
>   	if (count)
>   		return count;
> @@ -616,7 +611,7 @@ static ssize_t spufs_mbox_read(struct file *file, char __user *buf,
>   		 * but still need to return the data we have
>   		 * read successfully so far.
>   		 */
> -		ret = __put_user(mbox_data, udata);
> +		ret = put_user(mbox_data, udata);
>   		if (ret) {
>   			if (!count)
>   				count = -EFAULT;
> @@ -698,17 +693,12 @@ static ssize_t spufs_ibox_read(struct file *file, char __user *buf,
>   			size_t len, loff_t *pos)
>   {
>   	struct spu_context *ctx = file->private_data;
> -	u32 ibox_data, __user *udata;
> +	u32 ibox_data, __user *udata = (void __user *)buf;
>   	ssize_t count;
>   
>   	if (len < 4)
>   		return -EINVAL;
>   
> -	if (!access_ok(buf, len))
> -		return -EFAULT;
> -
> -	udata = (void __user *)buf;
> -
>   	count = spu_acquire(ctx);
>   	if (count)
>   		goto out;
> @@ -727,7 +717,7 @@ static ssize_t spufs_ibox_read(struct file *file, char __user *buf,
>   	}
>   
>   	/* if we can't write at all, return -EFAULT */
> -	count = __put_user(ibox_data, udata);
> +	count = put_user(ibox_data, udata);
>   	if (count)
>   		goto out_unlock;
>   
> @@ -741,7 +731,7 @@ static ssize_t spufs_ibox_read(struct file *file, char __user *buf,
>   		 * but still need to return the data we have
>   		 * read successfully so far.
>   		 */
> -		ret = __put_user(ibox_data, udata);
> +		ret = put_user(ibox_data, udata);
>   		if (ret)
>   			break;
>   	}
> @@ -836,17 +826,13 @@ static ssize_t spufs_wbox_write(struct file *file, const char __user *buf,
>   			size_t len, loff_t *pos)
>   {
>   	struct spu_context *ctx = file->private_data;
> -	u32 wbox_data, __user *udata;
> +	u32 wbox_data, __user *udata = (void __user *)buf;
>   	ssize_t count;
>   
>   	if (len < 4)
>   		return -EINVAL;
>   
> -	udata = (void __user *)buf;
> -	if (!access_ok(buf, len))
> -		return -EFAULT;
> -
> -	if (__get_user(wbox_data, udata))
> +	if (get_user(wbox_data, udata))
>   		return -EFAULT;
>   
>   	count = spu_acquire(ctx);
> @@ -873,7 +859,7 @@ static ssize_t spufs_wbox_write(struct file *file, const char __user *buf,
>   	/* write as much as possible */
>   	for (count = 4, udata++; (count + 4) <= len; count += 4, udata++) {
>   		int ret;
> -		ret = __get_user(wbox_data, udata);
> +		ret = get_user(wbox_data, udata);
>   		if (ret)
>   			break;
>   
> @@ -1982,9 +1968,6 @@ static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
>   	u32 stat, data;
>   	int ret;
>   
> -	if (!access_ok(buf, len))
> -		return -EFAULT;
> -
>   	ret = spu_acquire_saved(ctx);
>   	if (ret)
>   		return ret;
> @@ -2028,9 +2011,6 @@ static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
>   	u32 stat, data;
>   	int ret;
>   
> -	if (!access_ok(buf, len))
> -		return -EFAULT;
> -
>   	ret = spu_acquire_saved(ctx);
>   	if (ret)
>   		return ret;
> @@ -2082,9 +2062,6 @@ static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
>   	u32 data[ARRAY_SIZE(ctx->csa.spu_mailbox_data)];
>   	int ret, count;
>   
> -	if (!access_ok(buf, len))
> -		return -EFAULT;
> -
>   	ret = spu_acquire_saved(ctx);
>   	if (ret)
>   		return ret;
> @@ -2143,9 +2120,6 @@ static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
>   	struct spu_dma_info info;
>   	int ret;
>   
> -	if (!access_ok(buf, len))
> -		return -EFAULT;
> -
>   	ret = spu_acquire_saved(ctx);
>   	if (ret)
>   		return ret;
>