In a recent change to the Arm architecture with the end goal of removing
highmem we need to convert virt_to_phys() and virt_to_pfn() to static
inline functions.
This will make them strongly typed.
However since virt_to_* is always implemented as macros they have become
polymorphic and accept both (void *) and e.g. unsigned long as arguments.
Other functions such as virt_to_page() simply wrap virt_to_pfn() and get
affected indirectly.
To be able to proceed, patch mm to use (void *) as argument to affected
functions in all instances.
This patch (of 5):
A pointer into virtual memory is represented by a (void *) not an u32, so
the compiler warns:
lib/test_free_pages.c:20:50: warning: passing argument 1
of 'virt_to_pfn' makes pointer from integer without a
cast [-Wint-conversion]
Fix this with an explicit cast.
Link: https://lkml.kernel.org/r/20220630084124.691207-1-linus.walleij@linaro.org
Link: https://lkml.kernel.org/r/20220630084124.691207-2-linus.walleij@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Here is a very rare race which leaks memory:
Page P0 is allocated to the page cache. Page P1 is free.
Thread A Thread B Thread C
find_get_entry():
xas_load() returns P0
Removes P0 from page cache
P0 finds its buddy P1
alloc_pages(GFP_KERNEL, 1) returns P0
P0 has refcount 1
page_cache_get_speculative(P0)
P0 has refcount 2
__free_pages(P0)
P0 has refcount 1
put_page(P0)
P1 is not freed
Fix this by freeing all the pages in __free_pages() that won't be freed
by the call to put_page(). It's usually not a good idea to split a page,
but this is a very unlikely scenario.
Fixes: e286781d5f ("mm: speculative page references")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200926213919.26642-1-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
