| Message ID | 20211201142918.921493-19-Liam.Howlett@oracle.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Introducing the Maple Tree | expand |
On 12/1/21 15:29, Liam Howlett wrote: > From: "Liam R. Howlett" <Liam.Howlett@Oracle.com> > > vma_lookup() walks the VMA tree for a specific value, find_vma() will > search the tree after walking to a specific value. It is more efficient > to only walk to the requested value as this case requires the address to > equal the vm_start. By that you mean the privcmd_ioctl_mmap() code checks msg->va != vma->vm_start and thus we know it's never interested the next vma, that find_vma() can return if no vma covers the address? > Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> > --- > drivers/xen/privcmd.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c > index 3369734108af..ad17166b0ef6 100644 > --- a/drivers/xen/privcmd.c > +++ b/drivers/xen/privcmd.c > @@ -282,7 +282,7 @@ static long privcmd_ioctl_mmap(struct file *file, void __user *udata) > struct page, lru); > struct privcmd_mmap_entry *msg = page_address(page); > > - vma = find_vma(mm, msg->va); > + vma = vma_lookup(mm, msg->va); > rc = -EINVAL; > > if (!vma || (msg->va != vma->vm_start) || vma->vm_private_data)
* Vlastimil Babka <vbabka@suse.cz> [220112 11:01]: > On 12/1/21 15:29, Liam Howlett wrote: > > From: "Liam R. Howlett" <Liam.Howlett@Oracle.com> > > > > vma_lookup() walks the VMA tree for a specific value, find_vma() will > > search the tree after walking to a specific value. It is more efficient > > to only walk to the requested value as this case requires the address to > > equal the vm_start. > > By that you mean the privcmd_ioctl_mmap() code checks msg->va != > vma->vm_start and thus we know it's never interested the next vma, that > find_vma() can return if no vma covers the address? Yes. I will reword the commit message. > > > Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> > > Acked-by: Vlastimil Babka <vbabka@suse.cz> > > > --- > > drivers/xen/privcmd.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c > > index 3369734108af..ad17166b0ef6 100644 > > --- a/drivers/xen/privcmd.c > > +++ b/drivers/xen/privcmd.c > > @@ -282,7 +282,7 @@ static long privcmd_ioctl_mmap(struct file *file, void __user *udata) > > struct page, lru); > > struct privcmd_mmap_entry *msg = page_address(page); > > > > - vma = find_vma(mm, msg->va); > > + vma = vma_lookup(mm, msg->va); > > rc = -EINVAL; > > > > if (!vma || (msg->va != vma->vm_start) || vma->vm_private_data) >
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c index 3369734108af..ad17166b0ef6 100644 --- a/drivers/xen/privcmd.c +++ b/drivers/xen/privcmd.c @@ -282,7 +282,7 @@ static long privcmd_ioctl_mmap(struct file *file, void __user *udata) struct page, lru); struct privcmd_mmap_entry *msg = page_address(page); - vma = find_vma(mm, msg->va); + vma = vma_lookup(mm, msg->va); rc = -EINVAL; if (!vma || (msg->va != vma->vm_start) || vma->vm_private_data)