On 12/21/21 11:18 AM, Linus Torvalds wrote:

On Tue, Dec 21, 2021 at 11:15 AM Stefan Roesch [off-list ref] wrote:

quoted

Linus, if we remove the constness, then we either need to cast away the constness (the system call
is defined as const) or change the definition of the system call.

You could also do it as

        union {
                const void __user *setxattr_value;
                void __user *getxattr_value;
        };

Pavel brought up a very good point. By adding the kname array into the 
xarray_ctx we increase the size of io_xattr structure too much. In addition
this will also increase the size of the io_kiocb structure. The original
solution did not increase the size.

Per opcode we limit the storage space to 64 bytes. However the array itself
requires 256 bytes.
 

if you wanted to..

                 Linus