Re: [PATCH 1/1] mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()

From: Mark Salter
Date: Mon Jul 27 2015 - 15:35:04 EST


On Fri, 2015-07-24 at 10:39 -0400, Paul Gortmaker wrote:
> On Thu, Jul 16, 2015 at 6:26 PM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
> > Add the additional "vm_flags_t vm_flags" argument to do_mmap_pgoff(),
> > rename it to do_mmap(), and re-introduce do_mmap_pgoff() as a simple
> > wrapper on top of do_mmap(). Perhaps we should update the callers of
> > do_mmap_pgoff() and kill it later.
>
> It seems that the version of this patch in linux-next breaks all nommu
> builds (m86k, some arm, etc).
>
> mm/nommu.c: In function 'do_mmap':
> mm/nommu.c:1248:30: error: 'vm_flags' redeclared as different kind of symbol
> mm/nommu.c:1241:15: note: previous definition of 'vm_flags' was here
> scripts/Makefile.build:258: recipe for target 'mm/nommu.o' failed
>
> http://kisskb.ellerman.id.au/kisskb/buildresult/12470285/
>
> Bisect says:
>
> 31705a3a633bb63683918f055fe6032939672b61 is the first bad commit
> commit 31705a3a633bb63683918f055fe6032939672b61
> Author: Oleg Nesterov <oleg@xxxxxxxxxx>
> Date: Fri Jul 24 09:20:30 2015 +1000
>
> mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()
>
> Paul.

This fixes the build error and runs fine on c6x:

diff --git a/mm/nommu.c b/mm/nommu.c
index 530eea5..af2196e 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1245,7 +1245,7 @@ unsigned long do_mmap(struct file *file,
struct vm_area_struct *vma;
struct vm_region *region;
struct rb_node *rb;
- unsigned long capabilities, vm_flags, result;
+ unsigned long capabilities, result;
int ret;

*populate = 0;
@@ -1263,7 +1263,7 @@ unsigned long do_mmap(struct file *file,

/* we've determined that we can make the mapping, now translate what we
* now know into VMA flags */
- vm_flags = determine_vm_flags(file, prot, flags, capabilities);
+ vm_flags |= determine_vm_flags(file, prot, flags, capabilities);

/* we're going to need to record the mapping */
region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);

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