* [PATCH] mm/memory.c: Convert to use vmf_error()
@ 2019-09-05 18:43 Souptick Joarder
2019-09-05 18:59 ` Matthew Wilcox
0 siblings, 1 reply; 3+ messages in thread
From: Souptick Joarder @ 2019-09-05 18:43 UTC (permalink / raw)
To: akpm, willy, rcampbell, jglisse, mhocko, aneesh.kumar, peterz,
airlied, thellstrom
Cc: linux-mm, linux-kernel, Souptick Joarder
Convert to use vmf_error() here.
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
---
mm/memory.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index e2bb51b..1302be32 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1750,13 +1750,10 @@ static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma,
} else {
return insert_pfn(vma, addr, pfn, pgprot, mkwrite);
}
-
- if (err == -ENOMEM)
- return VM_FAULT_OOM;
- if (err < 0 && err != -EBUSY)
- return VM_FAULT_SIGBUS;
-
- return VM_FAULT_NOPAGE;
+ if (!err || err == -EBUSY)
+ return VM_FAULT_NOPAGE;
+ else
+ return vmf_error(err);
}
vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
--
1.9.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] mm/memory.c: Convert to use vmf_error()
2019-09-05 18:43 [PATCH] mm/memory.c: Convert to use vmf_error() Souptick Joarder
@ 2019-09-05 18:59 ` Matthew Wilcox
2019-09-06 12:24 ` Souptick Joarder
0 siblings, 1 reply; 3+ messages in thread
From: Matthew Wilcox @ 2019-09-05 18:59 UTC (permalink / raw)
To: Souptick Joarder
Cc: akpm, rcampbell, jglisse, mhocko, aneesh.kumar, peterz, airlied,
thellstrom, linux-mm, linux-kernel
On Fri, Sep 06, 2019 at 12:13:00AM +0530, Souptick Joarder wrote:
> +++ b/mm/memory.c
> @@ -1750,13 +1750,10 @@ static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma,
> } else {
> return insert_pfn(vma, addr, pfn, pgprot, mkwrite);
> }
> -
> - if (err == -ENOMEM)
> - return VM_FAULT_OOM;
> - if (err < 0 && err != -EBUSY)
> - return VM_FAULT_SIGBUS;
> -
> - return VM_FAULT_NOPAGE;
> + if (!err || err == -EBUSY)
> + return VM_FAULT_NOPAGE;
> + else
> + return vmf_error(err);
> }
My plan is to convert insert_page() to return a VM_FAULT error code like
insert_pfn() does. Need to finish off the vm_insert_page() conversions
first ;-)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] mm/memory.c: Convert to use vmf_error()
2019-09-05 18:59 ` Matthew Wilcox
@ 2019-09-06 12:24 ` Souptick Joarder
0 siblings, 0 replies; 3+ messages in thread
From: Souptick Joarder @ 2019-09-06 12:24 UTC (permalink / raw)
To: Matthew Wilcox
Cc: Andrew Morton, Ralph Campbell, Jérôme Glisse,
Michal Hocko, Aneesh Kumar K.V, Peter Zijlstra, airlied,
Thomas Hellstrom, Linux-MM, linux-kernel
On Fri, Sep 6, 2019 at 12:29 AM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Fri, Sep 06, 2019 at 12:13:00AM +0530, Souptick Joarder wrote:
> > +++ b/mm/memory.c
> > @@ -1750,13 +1750,10 @@ static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma,
> > } else {
> > return insert_pfn(vma, addr, pfn, pgprot, mkwrite);
> > }
> > -
> > - if (err == -ENOMEM)
> > - return VM_FAULT_OOM;
> > - if (err < 0 && err != -EBUSY)
> > - return VM_FAULT_SIGBUS;
> > -
> > - return VM_FAULT_NOPAGE;
> > + if (!err || err == -EBUSY)
> > + return VM_FAULT_NOPAGE;
> > + else
> > + return vmf_error(err);
> > }
>
> My plan is to convert insert_page() to return a VM_FAULT error code like
> insert_pfn() does. Need to finish off the vm_insert_page() conversions
> first ;-)
Previously we have problem while converting vm_insert_page() to return
vm_fault_t.
vm_insert_page() is called from different drivers. Some of them are
already converted
to use vm_map_pages()/ vm_map_pages_zero(). But still we left with few users.
drivers/media/usb/usbvision/usbvision-video.c#L1045
mm/vmalloc.c#L2969
These 2 can be converted with something like vm_map_vmalloc_pages().
I am working on it. Will post it in sometime.
drivers/android/binder_alloc.c#L259 (have objection)
drivers/infiniband/hw/efa/efa_verbs.c#L1701
drivers/infiniband/hw/mlx5/main.c#L2085 (have objection as using
vm_map_pages_zero() doesn't make sense)
drivers/xen/gntalloc.c#L548 (have limitation)
kernel/kcov.c#L297 (have objection)
net/ipv4/tcp.c#L1799
net/packet/af_packet.c#L4453
But these are the places where replacing vm_insert_page() is bit
difficult/ have objection.
In some cases, maintainers/ reviewers will not agree to replace
vm_insert_page().
In other scenario, if we change return type of vm_insert_page() to vm_fault_t,
we end up with adding few lines of conversion code from vm_fault_t to errno
in drivers which is not a correct way to go with.
Any suggestion, how to solve this ?
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-09-05 18:59 ` Matthew Wilcox
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