include/net/netmem.h | 33 ++++++++++++++++----------------- net/core/netmem_priv.h | 16 ++++++++-------- 2 files changed, 24 insertions(+), 25 deletions(-)
Now that we have struct netmem_desc, it'd better access the pp fields
via struct netmem_desc rather than struct net_iov.
Introduce netmem_to_nmdesc() for safely converting netmem_ref to
netmem_desc regardless of the type underneath e.i. netmem_desc, net_iov.
While at it, remove __netmem_clear_lsb() and make netmem_to_nmdesc()
used instead.
Signed-off-by: Byungchul Park <byungchul@sk.com>
---
include/net/netmem.h | 33 ++++++++++++++++-----------------
net/core/netmem_priv.h | 16 ++++++++--------
2 files changed, 24 insertions(+), 25 deletions(-)
diff --git a/include/net/netmem.h b/include/net/netmem.h
index f7dacc9e75fd..33ae444a9745 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h
@@ -265,24 +265,23 @@ static inline struct netmem_desc *__netmem_to_nmdesc(netmem_ref netmem)
return (__force struct netmem_desc *)netmem;
}
-/* __netmem_clear_lsb - convert netmem_ref to struct net_iov * for access to
- * common fields.
- * @netmem: netmem reference to extract as net_iov.
+/* netmem_to_nmdesc - convert netmem_ref to struct netmem_desc * for
+ * access to common fields.
+ * @netmem: netmem reference to get netmem_desc.
*
- * All the sub types of netmem_ref (page, net_iov) have the same pp, pp_magic,
- * dma_addr, and pp_ref_count fields at the same offsets. Thus, we can access
- * these fields without a type check to make sure that the underlying mem is
- * net_iov or page.
+ * All the sub types of netmem_ref (netmem_desc, net_iov) have the same
+ * pp, pp_magic, dma_addr, and pp_ref_count fields via netmem_desc.
*
- * The resulting value of this function can only be used to access the fields
- * that are NET_IOV_ASSERT_OFFSET'd. Accessing any other fields will result in
- * undefined behavior.
- *
- * Return: the netmem_ref cast to net_iov* regardless of its underlying type.
+ * Return: the pointer to struct netmem_desc * regardless of its
+ * underlying type.
*/
-static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem)
+static inline struct netmem_desc *netmem_to_nmdesc(netmem_ref netmem)
{
- return (struct net_iov *)((__force unsigned long)netmem & ~NET_IOV);
+ if (netmem_is_net_iov(netmem))
+ return &((struct net_iov *)((__force unsigned long)netmem &
+ ~NET_IOV))->desc;
+
+ return __netmem_to_nmdesc(netmem);
}
/* XXX: How to extract netmem_desc from page must be changed, once
@@ -320,12 +319,12 @@ static inline struct page_pool *__netmem_get_pp(netmem_ref netmem)
static inline struct page_pool *netmem_get_pp(netmem_ref netmem)
{
- return __netmem_clear_lsb(netmem)->pp;
+ return netmem_to_nmdesc(netmem)->pp;
}
static inline atomic_long_t *netmem_get_pp_ref_count_ref(netmem_ref netmem)
{
- return &__netmem_clear_lsb(netmem)->pp_ref_count;
+ return &netmem_to_nmdesc(netmem)->pp_ref_count;
}
static inline bool netmem_is_pref_nid(netmem_ref netmem, int pref_nid)
@@ -390,7 +389,7 @@ static inline bool netmem_is_pfmemalloc(netmem_ref netmem)
static inline unsigned long netmem_get_dma_addr(netmem_ref netmem)
{
- return __netmem_clear_lsb(netmem)->dma_addr;
+ return netmem_to_nmdesc(netmem)->dma_addr;
}
void get_netmem(netmem_ref netmem);
diff --git a/net/core/netmem_priv.h b/net/core/netmem_priv.h
index cd95394399b4..23175cb2bd86 100644
--- a/net/core/netmem_priv.h
+++ b/net/core/netmem_priv.h
@@ -5,19 +5,19 @@
static inline unsigned long netmem_get_pp_magic(netmem_ref netmem)
{
- return __netmem_clear_lsb(netmem)->pp_magic & ~PP_DMA_INDEX_MASK;
+ return netmem_to_nmdesc(netmem)->pp_magic & ~PP_DMA_INDEX_MASK;
}
static inline void netmem_or_pp_magic(netmem_ref netmem, unsigned long pp_magic)
{
- __netmem_clear_lsb(netmem)->pp_magic |= pp_magic;
+ netmem_to_nmdesc(netmem)->pp_magic |= pp_magic;
}
static inline void netmem_clear_pp_magic(netmem_ref netmem)
{
- WARN_ON_ONCE(__netmem_clear_lsb(netmem)->pp_magic & PP_DMA_INDEX_MASK);
+ WARN_ON_ONCE(netmem_to_nmdesc(netmem)->pp_magic & PP_DMA_INDEX_MASK);
- __netmem_clear_lsb(netmem)->pp_magic = 0;
+ netmem_to_nmdesc(netmem)->pp_magic = 0;
}
static inline bool netmem_is_pp(netmem_ref netmem)
@@ -27,13 +27,13 @@ static inline bool netmem_is_pp(netmem_ref netmem)
static inline void netmem_set_pp(netmem_ref netmem, struct page_pool *pool)
{
- __netmem_clear_lsb(netmem)->pp = pool;
+ netmem_to_nmdesc(netmem)->pp = pool;
}
static inline void netmem_set_dma_addr(netmem_ref netmem,
unsigned long dma_addr)
{
- __netmem_clear_lsb(netmem)->dma_addr = dma_addr;
+ netmem_to_nmdesc(netmem)->dma_addr = dma_addr;
}
static inline unsigned long netmem_get_dma_index(netmem_ref netmem)
@@ -43,7 +43,7 @@ static inline unsigned long netmem_get_dma_index(netmem_ref netmem)
if (WARN_ON_ONCE(netmem_is_net_iov(netmem)))
return 0;
- magic = __netmem_clear_lsb(netmem)->pp_magic;
+ magic = netmem_to_nmdesc(netmem)->pp_magic;
return (magic & PP_DMA_INDEX_MASK) >> PP_DMA_INDEX_SHIFT;
}
@@ -57,6 +57,6 @@ static inline void netmem_set_dma_index(netmem_ref netmem,
return;
magic = netmem_get_pp_magic(netmem) | (id << PP_DMA_INDEX_SHIFT);
- __netmem_clear_lsb(netmem)->pp_magic = magic;
+ netmem_to_nmdesc(netmem)->pp_magic = magic;
}
#endif
base-commit: fa582ca7e187a15e772e6a72fe035f649b387a60
--
2.17.1On Sun, Jul 27, 2025 at 9:21 PM Byungchul Park <byungchul@sk.com> wrote:
>
> Now that we have struct netmem_desc, it'd better access the pp fields
> via struct netmem_desc rather than struct net_iov.
>
> Introduce netmem_to_nmdesc() for safely converting netmem_ref to
> netmem_desc regardless of the type underneath e.i. netmem_desc, net_iov.
>
> While at it, remove __netmem_clear_lsb() and make netmem_to_nmdesc()
> used instead.
>
> Signed-off-by: Byungchul Park <byungchul@sk.com>
Thank you for working on paying this tech debt!
> ---
> include/net/netmem.h | 33 ++++++++++++++++-----------------
> net/core/netmem_priv.h | 16 ++++++++--------
> 2 files changed, 24 insertions(+), 25 deletions(-)
>
> diff --git a/include/net/netmem.h b/include/net/netmem.h
> index f7dacc9e75fd..33ae444a9745 100644
> --- a/include/net/netmem.h
> +++ b/include/net/netmem.h
> @@ -265,24 +265,23 @@ static inline struct netmem_desc *__netmem_to_nmdesc(netmem_ref netmem)
> return (__force struct netmem_desc *)netmem;
> }
>
> -/* __netmem_clear_lsb - convert netmem_ref to struct net_iov * for access to
> - * common fields.
> - * @netmem: netmem reference to extract as net_iov.
> +/* netmem_to_nmdesc - convert netmem_ref to struct netmem_desc * for
> + * access to common fields.
> + * @netmem: netmem reference to get netmem_desc.
> *
> - * All the sub types of netmem_ref (page, net_iov) have the same pp, pp_magic,
> - * dma_addr, and pp_ref_count fields at the same offsets. Thus, we can access
> - * these fields without a type check to make sure that the underlying mem is
> - * net_iov or page.
> + * All the sub types of netmem_ref (netmem_desc, net_iov) have the same
> + * pp, pp_magic, dma_addr, and pp_ref_count fields via netmem_desc.
> *
> - * The resulting value of this function can only be used to access the fields
> - * that are NET_IOV_ASSERT_OFFSET'd. Accessing any other fields will result in
> - * undefined behavior.
> - *
I think instead of removing this warning, we want to add an
NET_IOV_ASSERT_OFFSET that asserts that net_iov->netmem_desc and
page->netmem_desc are in the same offset, and then add a note here
that this works because we assert that the netmem_desc offset in both
net_iov and page are the same.
> - * Return: the netmem_ref cast to net_iov* regardless of its underlying type.
> + * Return: the pointer to struct netmem_desc * regardless of its
> + * underlying type.
> */
> -static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem)
> +static inline struct netmem_desc *netmem_to_nmdesc(netmem_ref netmem)
> {
> - return (struct net_iov *)((__force unsigned long)netmem & ~NET_IOV);
> + if (netmem_is_net_iov(netmem))
> + return &((struct net_iov *)((__force unsigned long)netmem &
> + ~NET_IOV))->desc;
> +
> + return __netmem_to_nmdesc(netmem);
The if statement generates overhead. I'd rather avoid it. We can
implement netmem_to_nmdesc like this, no?
netmem_to_nmdesc(netmem_ref netmem)
{
return (struct netmem_desc)((__force unsigned long)netmem & ~NET_IOV);
}
Because netmem_desc is the first element in both net_iov and page for
the moment. (yes I know that will change eventually, but we don't have
to incur overhead of an extra if statement until netmem_desc is
removed from page, right?)
--
Thanks,
Mina
On Mon, Jul 28, 2025 at 10:44:31AM -0700, Mina Almasry wrote:
> On Sun, Jul 27, 2025 at 9:21 PM Byungchul Park <byungchul@sk.com> wrote:
> >
> > Now that we have struct netmem_desc, it'd better access the pp fields
> > via struct netmem_desc rather than struct net_iov.
> >
> > Introduce netmem_to_nmdesc() for safely converting netmem_ref to
> > netmem_desc regardless of the type underneath e.i. netmem_desc, net_iov.
> >
> > While at it, remove __netmem_clear_lsb() and make netmem_to_nmdesc()
> > used instead.
> >
> > Signed-off-by: Byungchul Park <byungchul@sk.com>
>
> Thank you for working on paying this tech debt!
I thought it was appropriate to organize the code I modified to some
extent.
> > ---
> > include/net/netmem.h | 33 ++++++++++++++++-----------------
> > net/core/netmem_priv.h | 16 ++++++++--------
> > 2 files changed, 24 insertions(+), 25 deletions(-)
> >
> > diff --git a/include/net/netmem.h b/include/net/netmem.h
> > index f7dacc9e75fd..33ae444a9745 100644
> > --- a/include/net/netmem.h
> > +++ b/include/net/netmem.h
> > @@ -265,24 +265,23 @@ static inline struct netmem_desc *__netmem_to_nmdesc(netmem_ref netmem)
> > return (__force struct netmem_desc *)netmem;
> > }
> >
> > -/* __netmem_clear_lsb - convert netmem_ref to struct net_iov * for access to
> > - * common fields.
> > - * @netmem: netmem reference to extract as net_iov.
> > +/* netmem_to_nmdesc - convert netmem_ref to struct netmem_desc * for
> > + * access to common fields.
> > + * @netmem: netmem reference to get netmem_desc.
> > *
> > - * All the sub types of netmem_ref (page, net_iov) have the same pp, pp_magic,
> > - * dma_addr, and pp_ref_count fields at the same offsets. Thus, we can access
> > - * these fields without a type check to make sure that the underlying mem is
> > - * net_iov or page.
> > + * All the sub types of netmem_ref (netmem_desc, net_iov) have the same
> > + * pp, pp_magic, dma_addr, and pp_ref_count fields via netmem_desc.
> > *
> > - * The resulting value of this function can only be used to access the fields
> > - * that are NET_IOV_ASSERT_OFFSET'd. Accessing any other fields will result in
> > - * undefined behavior.
> > - *
>
> I think instead of removing this warning, we want to add an
> NET_IOV_ASSERT_OFFSET that asserts that net_iov->netmem_desc and
> page->netmem_desc are in the same offset, and then add a note here
> that this works because we assert that the netmem_desc offset in both
> net_iov and page are the same.
It doesn't have to have the same offset. Why do you want it? Is it for
some optimizaiton? Or I think it's unnecessary constraint.
> > - * Return: the netmem_ref cast to net_iov* regardless of its underlying type.
> > + * Return: the pointer to struct netmem_desc * regardless of its
> > + * underlying type.
> > */
> > -static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem)
> > +static inline struct netmem_desc *netmem_to_nmdesc(netmem_ref netmem)
> > {
> > - return (struct net_iov *)((__force unsigned long)netmem & ~NET_IOV);
> > + if (netmem_is_net_iov(netmem))
> > + return &((struct net_iov *)((__force unsigned long)netmem &
> > + ~NET_IOV))->desc;
> > +
> > + return __netmem_to_nmdesc(netmem);
>
> The if statement generates overhead. I'd rather avoid it. We can
> implement netmem_to_nmdesc like this, no?
>
> netmem_to_nmdesc(netmem_ref netmem)
> {
> return (struct netmem_desc)((__force unsigned long)netmem & ~NET_IOV);
> }
I see. You want this kind of optimization. I will do this way if you
want.
> Because netmem_desc is the first element in both net_iov and page for
> the moment. (yes I know that will change eventually, but we don't have
> to incur overhead of an extra if statement until netmem_desc is
> removed from page, right?)
Okay.
Byungchul
>
>
> --
> Thanks,
> Mina
On 7/28/25 18:44, Mina Almasry wrote:
> On Sun, Jul 27, 2025 at 9:21 PM Byungchul Park <byungchul@sk.com> wrote:
>>
...>> - * Return: the netmem_ref cast to net_iov* regardless of its underlying type.
>> + * Return: the pointer to struct netmem_desc * regardless of its
>> + * underlying type.
>> */
>> -static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem)
>> +static inline struct netmem_desc *netmem_to_nmdesc(netmem_ref netmem)
>> {
>> - return (struct net_iov *)((__force unsigned long)netmem & ~NET_IOV);
>> + if (netmem_is_net_iov(netmem))
>> + return &((struct net_iov *)((__force unsigned long)netmem &
>> + ~NET_IOV))->desc;
>> +
>> + return __netmem_to_nmdesc(netmem);
>
> The if statement generates overhead. I'd rather avoid it. We can
> implement netmem_to_nmdesc like this, no?
>
> netmem_to_nmdesc(netmem_ref netmem)
> {
> return (struct netmem_desc)((__force unsigned long)netmem & ~NET_IOV);
> }
>
> Because netmem_desc is the first element in both net_iov and page for
> the moment. (yes I know that will change eventually, but we don't have
> to incur overhead of an extra if statement until netmem_desc is
> removed from page, right?)
Same concern, but I think the goal here should be to make enough
info to the compiler to optimise it out without assumptions on
the layouts nor NET_IOV_ASSERT_OFFSET. Currently it's not so bad,
but we should be able to remove this test+cmove.
movq %rdi, %rax # netmem, tmp105
andq $-2, %rax #, tmp105
testb $1, %dil #, netmem
cmove %rdi, %rax # tmp105,, netmem, <retval>
jmp __x86_return_thunk
--
Pavel Begunkov
On 7/28/25 19:46, Pavel Begunkov wrote:
> On 7/28/25 18:44, Mina Almasry wrote:
>> On Sun, Jul 27, 2025 at 9:21 PM Byungchul Park <byungchul@sk.com> wrote:
>>>
>
> ...>> - * Return: the netmem_ref cast to net_iov* regardless of its underlying type.
>>> + * Return: the pointer to struct netmem_desc * regardless of its
>>> + * underlying type.
>>> */
>>> -static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem)
>>> +static inline struct netmem_desc *netmem_to_nmdesc(netmem_ref netmem)
>>> {
>>> - return (struct net_iov *)((__force unsigned long)netmem & ~NET_IOV);
>>> + if (netmem_is_net_iov(netmem))
>>> + return &((struct net_iov *)((__force unsigned long)netmem &
>>> + ~NET_IOV))->desc;
>>> +
>>> + return __netmem_to_nmdesc(netmem);
>>
>> The if statement generates overhead. I'd rather avoid it. We can
>> implement netmem_to_nmdesc like this, no?
>>
>> netmem_to_nmdesc(netmem_ref netmem)
>> {
>> return (struct netmem_desc)((__force unsigned long)netmem & ~NET_IOV);
>> }
>>
>> Because netmem_desc is the first element in both net_iov and page for
>> the moment. (yes I know that will change eventually, but we don't have
>> to incur overhead of an extra if statement until netmem_desc is
>> removed from page, right?)
>
> Same concern, but I think the goal here should be to make enough
s/make/give/
> info to the compiler to optimise it out without assumptions on
> the layouts nor NET_IOV_ASSERT_OFFSET. Currently it's not so bad,
> but we should be able to remove this test+cmove.
>
> movq %rdi, %rax # netmem, tmp105
> andq $-2, %rax #, tmp105
> testb $1, %dil #, netmem
> cmove %rdi, %rax # tmp105,, netmem, <retval>
> jmp __x86_return_thunk
struct netmem_desc *netmem_to_nmdesc(netmem_ref netmem)
{
void *p = (void *)((__force unsigned long)netmem & ~NET_IOV);
if (netmem_is_net_iov(netmem))
return &((struct net_iov *)p)->desc;
return __pp_page_to_nmdesc((struct page *)p);
}
movq %rdi, %rax # netmem, netmem
andq $-2, %rax #, netmem
jmp __x86_return_thunk
This should do it, and if the layouts change, it'd still
remain correct.
--
Pavel Begunkov
On Mon, Jul 28, 2025 at 07:58:13PM +0100, Pavel Begunkov wrote:
> On 7/28/25 19:46, Pavel Begunkov wrote:
> > On 7/28/25 18:44, Mina Almasry wrote:
> > > On Sun, Jul 27, 2025 at 9:21 PM Byungchul Park <byungchul@sk.com> wrote:
> > > >
> >
> > ...>> - * Return: the netmem_ref cast to net_iov* regardless of its underlying type.
> > > > + * Return: the pointer to struct netmem_desc * regardless of its
> > > > + * underlying type.
> > > > */
> > > > -static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem)
> > > > +static inline struct netmem_desc *netmem_to_nmdesc(netmem_ref netmem)
> > > > {
> > > > - return (struct net_iov *)((__force unsigned long)netmem & ~NET_IOV);
> > > > + if (netmem_is_net_iov(netmem))
> > > > + return &((struct net_iov *)((__force unsigned long)netmem &
> > > > + ~NET_IOV))->desc;
> > > > +
> > > > + return __netmem_to_nmdesc(netmem);
> > >
> > > The if statement generates overhead. I'd rather avoid it. We can
> > > implement netmem_to_nmdesc like this, no?
> > >
> > > netmem_to_nmdesc(netmem_ref netmem)
> > > {
> > > return (struct netmem_desc)((__force unsigned long)netmem & ~NET_IOV);
> > > }
> > >
> > > Because netmem_desc is the first element in both net_iov and page for
> > > the moment. (yes I know that will change eventually, but we don't have
> > > to incur overhead of an extra if statement until netmem_desc is
> > > removed from page, right?)
> >
> > Same concern, but I think the goal here should be to make enough
>
> s/make/give/
>
>
> > info to the compiler to optimise it out without assumptions on
> > the layouts nor NET_IOV_ASSERT_OFFSET. Currently it's not so bad,
> > but we should be able to remove this test+cmove.
> >
> > movq %rdi, %rax # netmem, tmp105
> > andq $-2, %rax #, tmp105
> > testb $1, %dil #, netmem
> > cmove %rdi, %rax # tmp105,, netmem, <retval>
> > jmp __x86_return_thunk
>
> struct netmem_desc *netmem_to_nmdesc(netmem_ref netmem)
> {
> void *p = (void *)((__force unsigned long)netmem & ~NET_IOV);
>
> if (netmem_is_net_iov(netmem))
> return &((struct net_iov *)p)->desc;
> return __pp_page_to_nmdesc((struct page *)p);
> }
I wanted to remove constraints that can be removed, but Mina want not to
add additional overhead more. So I'm thinking to keep the constraint,
'netmem_desc is the first member of net_iov'.
Thoughts?
Byungchul
> movq %rdi, %rax # netmem, netmem
> andq $-2, %rax #, netmem
> jmp __x86_return_thunk
>
>
> This should do it, and if the layouts change, it'd still
> remain correct.
>
> --
> Pavel Begunkov
On 7/29/25 02:17, Byungchul Park wrote:
> On Mon, Jul 28, 2025 at 07:58:13PM +0100, Pavel Begunkov wrote:
>> On 7/28/25 19:46, Pavel Begunkov wrote:
>>> On 7/28/25 18:44, Mina Almasry wrote:
>>>> On Sun, Jul 27, 2025 at 9:21 PM Byungchul Park <byungchul@sk.com> wrote:
...>>
>>
>>> info to the compiler to optimise it out without assumptions on
>>> the layouts nor NET_IOV_ASSERT_OFFSET. Currently it's not so bad,
>>> but we should be able to remove this test+cmove.
>>>
>>> movq %rdi, %rax # netmem, tmp105
>>> andq $-2, %rax #, tmp105
>>> testb $1, %dil #, netmem
>>> cmove %rdi, %rax # tmp105,, netmem, <retval>
>>> jmp __x86_return_thunk
>>
>> struct netmem_desc *netmem_to_nmdesc(netmem_ref netmem)
>> {
>> void *p = (void *)((__force unsigned long)netmem & ~NET_IOV);
>>
>> if (netmem_is_net_iov(netmem))
>> return &((struct net_iov *)p)->desc;
>> return __pp_page_to_nmdesc((struct page *)p);
>> }
>
> I wanted to remove constraints that can be removed, but Mina want not to
> add additional overhead more. So I'm thinking to keep the constraint,
> 'netmem_desc is the first member of net_iov'.
>
> Thoughts?
We don't want extra overhead, the function above doesn't add
any, so just use it. You don't need to explicitly check that
layouts match.
--
Pavel Begunkov
> Now that we have struct netmem_desc, it'd better access the pp fields
> via struct netmem_desc rather than struct net_iov.
>
> Introduce netmem_to_nmdesc() for safely converting netmem_ref to
> netmem_desc regardless of the type underneath e.i. netmem_desc, net_iov.
>
> While at it, remove __netmem_clear_lsb() and make netmem_to_nmdesc()
> used instead.
+cc kernel_team@skhynix.com
Byungchul
> Signed-off-by: Byungchul Park <byungchul@sk.com>
> ---
> include/net/netmem.h | 33 ++++++++++++++++-----------------
> net/core/netmem_priv.h | 16 ++++++++--------
> 2 files changed, 24 insertions(+), 25 deletions(-)
>
> diff --git a/include/net/netmem.h b/include/net/netmem.h
> index f7dacc9e75fd..33ae444a9745 100644
> --- a/include/net/netmem.h
> +++ b/include/net/netmem.h
> @@ -265,24 +265,23 @@ static inline struct netmem_desc *__netmem_to_nmdesc(netmem_ref netmem)
> return (__force struct netmem_desc *)netmem;
> }
>
> -/* __netmem_clear_lsb - convert netmem_ref to struct net_iov * for access to
> - * common fields.
> - * @netmem: netmem reference to extract as net_iov.
> +/* netmem_to_nmdesc - convert netmem_ref to struct netmem_desc * for
> + * access to common fields.
> + * @netmem: netmem reference to get netmem_desc.
> *
> - * All the sub types of netmem_ref (page, net_iov) have the same pp, pp_magic,
> - * dma_addr, and pp_ref_count fields at the same offsets. Thus, we can access
> - * these fields without a type check to make sure that the underlying mem is
> - * net_iov or page.
> + * All the sub types of netmem_ref (netmem_desc, net_iov) have the same
> + * pp, pp_magic, dma_addr, and pp_ref_count fields via netmem_desc.
> *
> - * The resulting value of this function can only be used to access the fields
> - * that are NET_IOV_ASSERT_OFFSET'd. Accessing any other fields will result in
> - * undefined behavior.
> - *
> - * Return: the netmem_ref cast to net_iov* regardless of its underlying type.
> + * Return: the pointer to struct netmem_desc * regardless of its
> + * underlying type.
> */
> -static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem)
> +static inline struct netmem_desc *netmem_to_nmdesc(netmem_ref netmem)
> {
> - return (struct net_iov *)((__force unsigned long)netmem & ~NET_IOV);
> + if (netmem_is_net_iov(netmem))
> + return &((struct net_iov *)((__force unsigned long)netmem &
> + ~NET_IOV))->desc;
> +
> + return __netmem_to_nmdesc(netmem);
> }
>
> /* XXX: How to extract netmem_desc from page must be changed, once
> @@ -320,12 +319,12 @@ static inline struct page_pool *__netmem_get_pp(netmem_ref netmem)
>
> static inline struct page_pool *netmem_get_pp(netmem_ref netmem)
> {
> - return __netmem_clear_lsb(netmem)->pp;
> + return netmem_to_nmdesc(netmem)->pp;
> }
>
> static inline atomic_long_t *netmem_get_pp_ref_count_ref(netmem_ref netmem)
> {
> - return &__netmem_clear_lsb(netmem)->pp_ref_count;
> + return &netmem_to_nmdesc(netmem)->pp_ref_count;
> }
>
> static inline bool netmem_is_pref_nid(netmem_ref netmem, int pref_nid)
> @@ -390,7 +389,7 @@ static inline bool netmem_is_pfmemalloc(netmem_ref netmem)
>
> static inline unsigned long netmem_get_dma_addr(netmem_ref netmem)
> {
> - return __netmem_clear_lsb(netmem)->dma_addr;
> + return netmem_to_nmdesc(netmem)->dma_addr;
> }
>
> void get_netmem(netmem_ref netmem);
> diff --git a/net/core/netmem_priv.h b/net/core/netmem_priv.h
> index cd95394399b4..23175cb2bd86 100644
> --- a/net/core/netmem_priv.h
> +++ b/net/core/netmem_priv.h
> @@ -5,19 +5,19 @@
>
> static inline unsigned long netmem_get_pp_magic(netmem_ref netmem)
> {
> - return __netmem_clear_lsb(netmem)->pp_magic & ~PP_DMA_INDEX_MASK;
> + return netmem_to_nmdesc(netmem)->pp_magic & ~PP_DMA_INDEX_MASK;
> }
>
> static inline void netmem_or_pp_magic(netmem_ref netmem, unsigned long pp_magic)
> {
> - __netmem_clear_lsb(netmem)->pp_magic |= pp_magic;
> + netmem_to_nmdesc(netmem)->pp_magic |= pp_magic;
> }
>
> static inline void netmem_clear_pp_magic(netmem_ref netmem)
> {
> - WARN_ON_ONCE(__netmem_clear_lsb(netmem)->pp_magic & PP_DMA_INDEX_MASK);
> + WARN_ON_ONCE(netmem_to_nmdesc(netmem)->pp_magic & PP_DMA_INDEX_MASK);
>
> - __netmem_clear_lsb(netmem)->pp_magic = 0;
> + netmem_to_nmdesc(netmem)->pp_magic = 0;
> }
>
> static inline bool netmem_is_pp(netmem_ref netmem)
> @@ -27,13 +27,13 @@ static inline bool netmem_is_pp(netmem_ref netmem)
>
> static inline void netmem_set_pp(netmem_ref netmem, struct page_pool *pool)
> {
> - __netmem_clear_lsb(netmem)->pp = pool;
> + netmem_to_nmdesc(netmem)->pp = pool;
> }
>
> static inline void netmem_set_dma_addr(netmem_ref netmem,
> unsigned long dma_addr)
> {
> - __netmem_clear_lsb(netmem)->dma_addr = dma_addr;
> + netmem_to_nmdesc(netmem)->dma_addr = dma_addr;
> }
>
> static inline unsigned long netmem_get_dma_index(netmem_ref netmem)
> @@ -43,7 +43,7 @@ static inline unsigned long netmem_get_dma_index(netmem_ref netmem)
> if (WARN_ON_ONCE(netmem_is_net_iov(netmem)))
> return 0;
>
> - magic = __netmem_clear_lsb(netmem)->pp_magic;
> + magic = netmem_to_nmdesc(netmem)->pp_magic;
>
> return (magic & PP_DMA_INDEX_MASK) >> PP_DMA_INDEX_SHIFT;
> }
> @@ -57,6 +57,6 @@ static inline void netmem_set_dma_index(netmem_ref netmem,
> return;
>
> magic = netmem_get_pp_magic(netmem) | (id << PP_DMA_INDEX_SHIFT);
> - __netmem_clear_lsb(netmem)->pp_magic = magic;
> + netmem_to_nmdesc(netmem)->pp_magic = magic;
> }
> #endif
>
> base-commit: fa582ca7e187a15e772e6a72fe035f649b387a60
> --
> 2.17.1
>
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