From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Rapoport Subject: Re: [PATCH] memblock: stop using implicit alignement to SMP_CACHE_BYTES Date: Thu, 11 Oct 2018 09:08:50 +0300 Message-ID: <20181011060850.GA19822@rapoport-lnx> References: <1538687224-17535-1-git-send-email-rppt@linux.vnet.ibm.com> <20181005151934.87226fa92825c3002a475413@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20181005151934.87226fa92825c3002a475413@linux-foundation.org> Sender: linux-kernel-owner@vger.kernel.org To: Andrew Morton Cc: linux-mm@kvack.org, Catalin Marinas , Chris Zankel , Geert Uytterhoeven , Guan Xuetao , Ingo Molnar , Matt Turner , Michael Ellerman , Michal Hocko , Michal Simek , Paul Burton , Richard Weinberger , Russell King , Thomas Gleixner , Tony Luck , linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@vger.kernel.org, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, linux-um@lists.infradead.org List-Id: linux-m68k@vger.kernel.org On Fri, Oct 05, 2018 at 03:19:34PM -0700, Andrew Morton wrote: > On Fri, 5 Oct 2018 00:07:04 +0300 Mike Rapoport wrote: > > > When a memblock allocation APIs are called with align = 0, the alignment is > > implicitly set to SMP_CACHE_BYTES. > > > > Replace all such uses of memblock APIs with the 'align' parameter explicitly > > set to SMP_CACHE_BYTES and stop implicit alignment assignment in the > > memblock internal allocation functions. > > > > For the case when memblock APIs are used via helper functions, e.g. like > > iommu_arena_new_node() in Alpha, the helper functions were detected with > > Coccinelle's help and then manually examined and updated where appropriate. > > > > ... > > > > --- a/mm/memblock.c > > +++ b/mm/memblock.c > > @@ -1298,9 +1298,6 @@ static phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size, > > { > > phys_addr_t found; > > > > - if (!align) > > - align = SMP_CACHE_BYTES; > > - > > Can we add a WARN_ON_ONCE(!align) here? To catch unconverted code > which sneaks in later on. Here it goes: >>From baec825c58e8bc11371433d3a4b20b2216877a50 Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Mon, 8 Oct 2018 11:22:10 +0300 Subject: [PATCH] memblock: warn if zero alignment was requested After update of all memblock users to explicitly specify SMP_CACHE_BYTES alignment rather than use 0, it is still possible that uncovered users may sneak in. Add a WARN_ON_ONCE for such cases. Signed-off-by: Mike Rapoport --- mm/memblock.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/memblock.c b/mm/memblock.c index 0bbae56..5fefc70 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1298,6 +1298,9 @@ static phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size, { phys_addr_t found; + if (WARN_ON_ONCE(!align)) + align = SMP_CACHE_BYTES; + found = memblock_find_in_range_node(size, align, start, end, nid, flags); if (found && !memblock_reserve(found, size)) { @@ -1420,6 +1423,9 @@ static void * __init memblock_alloc_internal( if (WARN_ON_ONCE(slab_is_available())) return kzalloc_node(size, GFP_NOWAIT, nid); + if (WARN_ON_ONCE(!align)) + align = SMP_CACHE_BYTES; + if (max_addr > memblock.current_limit) max_addr = memblock.current_limit; again: -- 2.7.4 -- Sincerely yours, Mike.