From: Michael S. Tsirkin <mst@redhat.com>
Date: Sun, 14 Dec 2014 16:52:51 +0000 (+0200)
Subject: powerpc/uaccess: Allow get_user() with bitwise types
X-Git-Tag: omap-for-v3.19/fixes-rc1~29^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=505e428374bc17a2c0bd388c2e8d892e9cd8eef2;p=pandora-kernel.git

powerpc/uaccess: Allow get_user() with bitwise types

At the moment, if p and x are both of the same bitwise type
(eg. __le32), get_user(x, p) produces a sparse warning.

This is because *p is loaded into a long then cast back to typeof(*p).

When typeof(*p) is a bitwise type (which is uncommon), such a cast needs
__force, otherwise sparse produces a warning.

For non-bitwise types __force should have no effect, and should not hide
any legitimate errors.

Note that we are casting to typeof(*p) not typeof(x). Even with the
cast, if x and *p are of different types we should get the warning, so I
think we are not loosing the ability to detect any actual errors.

virtio would like to use bitwise types with get_user() so fix these
spurious warnings by adding __force.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
[mpe: Fill in changelog with more details]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---

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