Replacement patch to fix compiler warning.
From: "Matthew Wilcox (Oracle)"
Date: Fri, 16 Apr 2021 16:34:55 -0400
Subject: [PATCH 1/2] mm: Fix struct page layout on 32-bit systems
To: bro...@redhat.com
Cc: linux-ker...@vger.kernel.org,
linux...@kvack.org,
net...@vger.kernel.org,
The net page_pool wants to use a magic value to identify page pool pages.
The best place to put it is in the first word where it can be clearly a
non-pointer value. That means shifting dma_addr up to alias with ->index,
which means we need to find another way to indicate page_is_pfmemalloc().
32-bit architectures which expect 8-byte alignment for 8-byte integers
and need 64-bit DMA addresses (arc, arm, mips, ppc) had their struct
page inadvertently expanded in 2019. When the dma_addr_t was added,
it forced the alignment of the union to 8 bytes, which inserted a 4 byte
gap between
The first patch here fixes two bugs on ppc32, and mips32. It fixes one
bug on arc and arm32 (in certain configurations). It probably makes
sense to get it in ASAP through the networking tree. I'd like to see
testing on those four architectures if possible?
The second patch enables new
