The devdax driver does nothing special in its f_op->mmap hook, so
straightforwardly update it to use the mmap_prepare hook instead.
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
drivers/dax/device.c | 32 +++++++++++++++++++++-----------
1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 2bb40a6060af..c2181439f925 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -13,8 +13,9 @@
#include "dax-private.h"
#include "bus.h"
-static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
- const char *func)
+static int __check_vma(struct dev_dax *dev_dax, vm_flags_t vm_flags,
+ unsigned long start, unsigned long end, struct file *file,
+ const char *func)
{
struct device *dev = &dev_dax->dev;
unsigned long mask;
@@ -23,7 +24,7 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
return -ENXIO;
/* prevent private mappings from being established */
- if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
+ if ((vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
dev_info_ratelimited(dev,
"%s: %s: fail, attempted private mapping\n",
current->comm, func);
@@ -31,15 +32,15 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
}
mask = dev_dax->align - 1;
- if (vma->vm_start & mask || vma->vm_end & mask) {
+ if (start & mask || end & mask) {
dev_info_ratelimited(dev,
"%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
- current->comm, func, vma->vm_start, vma->vm_end,
+ current->comm, func, start, end,
mask);
return -EINVAL;
}
- if (!vma_is_dax(vma)) {
+ if (!file_is_dax(file)) {
dev_info_ratelimited(dev,
"%s: %s: fail, vma is not DAX capable\n",
current->comm, func);
@@ -49,6 +50,13 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
return 0;
}
+static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
+ const char *func)
+{
+ return __check_vma(dev_dax, vma->vm_flags, vma->vm_start, vma->vm_end,
+ vma->vm_file, func);
+}
+
/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
__weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
unsigned long size)
@@ -285,8 +293,9 @@ static const struct vm_operations_struct dax_vm_ops = {
.pagesize = dev_dax_pagesize,
};
-static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
+static int dax_mmap_prepare(struct vm_area_desc *desc)
{
+ struct file *filp = desc->file;
struct dev_dax *dev_dax = filp->private_data;
int rc, id;
@@ -297,13 +306,14 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
* fault time.
*/
id = dax_read_lock();
- rc = check_vma(dev_dax, vma, __func__);
+ rc = __check_vma(dev_dax, desc->vm_flags, desc->start, desc->end, filp,
+ __func__);
dax_read_unlock(id);
if (rc)
return rc;
- vma->vm_ops = &dax_vm_ops;
- vm_flags_set(vma, VM_HUGEPAGE);
+ desc->vm_ops = &dax_vm_ops;
+ desc->vm_flags |= VM_HUGEPAGE;
return 0;
}
@@ -377,7 +387,7 @@ static const struct file_operations dax_fops = {
.open = dax_open,
.release = dax_release,
.get_unmapped_area = dax_get_unmapped_area,
- .mmap = dax_mmap,
+ .mmap_prepare = dax_mmap_prepare,
.fop_flags = FOP_MMAP_SYNC,
};
--
2.51.0On Tue, Sep 16, 2025 at 03:11:48PM +0100, Lorenzo Stoakes wrote:
> The devdax driver does nothing special in its f_op->mmap hook, so
> straightforwardly update it to use the mmap_prepare hook instead.
>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Acked-by: David Hildenbrand <david@redhat.com>
> Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Pedro Falcato <pfalcato@suse.de>
> ---
> drivers/dax/device.c | 32 +++++++++++++++++++++-----------
> 1 file changed, 21 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/dax/device.c b/drivers/dax/device.c
> index 2bb40a6060af..c2181439f925 100644
> --- a/drivers/dax/device.c
> +++ b/drivers/dax/device.c
> @@ -13,8 +13,9 @@
> #include "dax-private.h"
> #include "bus.h"
>
> -static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> - const char *func)
> +static int __check_vma(struct dev_dax *dev_dax, vm_flags_t vm_flags,
> + unsigned long start, unsigned long end, struct file *file,
> + const char *func)
> {
> struct device *dev = &dev_dax->dev;
> unsigned long mask;
> @@ -23,7 +24,7 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> return -ENXIO;
>
> /* prevent private mappings from being established */
> - if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
> + if ((vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
> dev_info_ratelimited(dev,
> "%s: %s: fail, attempted private mapping\n",
> current->comm, func);
> @@ -31,15 +32,15 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> }
>
> mask = dev_dax->align - 1;
> - if (vma->vm_start & mask || vma->vm_end & mask) {
> + if (start & mask || end & mask) {
> dev_info_ratelimited(dev,
> "%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
> - current->comm, func, vma->vm_start, vma->vm_end,
> + current->comm, func, start, end,
> mask);
> return -EINVAL;
> }
>
> - if (!vma_is_dax(vma)) {
> + if (!file_is_dax(file)) {
> dev_info_ratelimited(dev,
> "%s: %s: fail, vma is not DAX capable\n",
> current->comm, func);
> @@ -49,6 +50,13 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> return 0;
> }
>
> +static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> + const char *func)
> +{
> + return __check_vma(dev_dax, vma->vm_flags, vma->vm_start, vma->vm_end,
> + vma->vm_file, func);
> +}
> +
Side comment: I'm no DAX expert at all, but this check_vma() thing looks... smelly?
Besides the !dax_alive() check, I don't see the need to recheck vma limits at
every ->huge_fault() call. Even taking mremap() into account,
->get_unmapped_area() should Do The Right Thing, no?
--
Pedro
On Wed, Sep 17, 2025 at 11:37:07AM +0100, Pedro Falcato wrote:
> On Tue, Sep 16, 2025 at 03:11:48PM +0100, Lorenzo Stoakes wrote:
> > The devdax driver does nothing special in its f_op->mmap hook, so
> > straightforwardly update it to use the mmap_prepare hook instead.
> >
> > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> > Acked-by: David Hildenbrand <david@redhat.com>
> > Reviewed-by: Jan Kara <jack@suse.cz>
>
> Acked-by: Pedro Falcato <pfalcato@suse.de>
Thanks!
>
> > ---
> > drivers/dax/device.c | 32 +++++++++++++++++++++-----------
> > 1 file changed, 21 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/dax/device.c b/drivers/dax/device.c
> > index 2bb40a6060af..c2181439f925 100644
> > --- a/drivers/dax/device.c
> > +++ b/drivers/dax/device.c
> > @@ -13,8 +13,9 @@
> > #include "dax-private.h"
> > #include "bus.h"
> >
> > -static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> > - const char *func)
> > +static int __check_vma(struct dev_dax *dev_dax, vm_flags_t vm_flags,
> > + unsigned long start, unsigned long end, struct file *file,
> > + const char *func)
> > {
> > struct device *dev = &dev_dax->dev;
> > unsigned long mask;
> > @@ -23,7 +24,7 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> > return -ENXIO;
> >
> > /* prevent private mappings from being established */
> > - if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
> > + if ((vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
> > dev_info_ratelimited(dev,
> > "%s: %s: fail, attempted private mapping\n",
> > current->comm, func);
> > @@ -31,15 +32,15 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> > }
> >
> > mask = dev_dax->align - 1;
> > - if (vma->vm_start & mask || vma->vm_end & mask) {
> > + if (start & mask || end & mask) {
> > dev_info_ratelimited(dev,
> > "%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
> > - current->comm, func, vma->vm_start, vma->vm_end,
> > + current->comm, func, start, end,
> > mask);
> > return -EINVAL;
> > }
> >
> > - if (!vma_is_dax(vma)) {
> > + if (!file_is_dax(file)) {
> > dev_info_ratelimited(dev,
> > "%s: %s: fail, vma is not DAX capable\n",
> > current->comm, func);
> > @@ -49,6 +50,13 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> > return 0;
> > }
> >
> > +static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> > + const char *func)
> > +{
> > + return __check_vma(dev_dax, vma->vm_flags, vma->vm_start, vma->vm_end,
> > + vma->vm_file, func);
> > +}
> > +
>
> Side comment: I'm no DAX expert at all, but this check_vma() thing looks... smelly?
> Besides the !dax_alive() check, I don't see the need to recheck vma limits at
> every ->huge_fault() call. Even taking mremap() into account,
> ->get_unmapped_area() should Do The Right Thing, no?
Let's keep this out of the series though please, am only humbly converting ->
mmap_prepare, this series isn't about solving the problems of every mmap caller
:)
>
> --
> Pedro
Thanks, Lorenzo
On Tue, Sep 16, 2025 at 03:11:48PM +0100, Lorenzo Stoakes wrote: > The devdax driver does nothing special in its f_op->mmap hook, so > straightforwardly update it to use the mmap_prepare hook instead. > > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> > Acked-by: David Hildenbrand <david@redhat.com> > Reviewed-by: Jan Kara <jack@suse.cz> > --- > drivers/dax/device.c | 32 +++++++++++++++++++++----------- > 1 file changed, 21 insertions(+), 11 deletions(-) Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Jason
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