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SubjectRe: [PATCH 8/9] xen/gntdev.c: Convert to use vm_insert_range
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On 1/14/19 11:49 PM, Souptick Joarder wrote:
> On Tue, Jan 15, 2019 at 4:58 AM Boris Ostrovsky
> <boris.ostrovsky@oracle.com> wrote:
>> On 1/11/19 10:12 AM, Souptick Joarder wrote:
>>> Convert to use vm_insert_range() to map range of kernel
>>> memory to user vma.
>>>
>>> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>
>> (although it would be good to mention in the commit that you are also
>> replacing count with vma_pages(vma), and why)
> The original code was using count ( *count = vma_pages(vma)* )
> which is same as this patch. Do I need capture it change log ?


I'd just say that because theoretically count might not be equal to
map->count we should use the latter as input to vm_insert_range().

Thanks.
-boris



>
>>
>>> ---
>>> drivers/xen/gntdev.c | 16 ++++++----------
>>> 1 file changed, 6 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
>>> index b0b02a5..ca4acee 100644
>>> --- a/drivers/xen/gntdev.c
>>> +++ b/drivers/xen/gntdev.c
>>> @@ -1082,18 +1082,17 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
>>> {
>>> struct gntdev_priv *priv = flip->private_data;
>>> int index = vma->vm_pgoff;
>>> - int count = vma_pages(vma);
>>> struct gntdev_grant_map *map;
>>> - int i, err = -EINVAL;
>>> + int err = -EINVAL;
>>>
>>> if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
>>> return -EINVAL;
>>>
>>> pr_debug("map %d+%d at %lx (pgoff %lx)\n",
>>> - index, count, vma->vm_start, vma->vm_pgoff);
>>> + index, vma_pages(vma), vma->vm_start, vma->vm_pgoff);
>>>
>>> mutex_lock(&priv->lock);
>>> - map = gntdev_find_map_index(priv, index, count);
>>> + map = gntdev_find_map_index(priv, index, vma_pages(vma));
>>> if (!map)
>>> goto unlock_out;
>>> if (use_ptemod && map->vma)
>>> @@ -1145,12 +1144,9 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
>>> goto out_put_map;
>>>
>>> if (!use_ptemod) {
>>> - for (i = 0; i < count; i++) {
>>> - err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE,
>>> - map->pages[i]);
>>> - if (err)
>>> - goto out_put_map;
>>> - }
>>> + err = vm_insert_range(vma, map->pages, map->count);
>>> + if (err)
>>> + goto out_put_map;
>>> } else {
>>> #ifdef CONFIG_X86
>>> /*

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