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[PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"

Huan Yang posted 2 patches 8 months, 1 week ago
There is a newer version of this series
[PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
Posted by Huan Yang 8 months, 1 week ago 
This reverts commit 18d7de823b7150344d242c3677e65d68c5271b04.

This given a misuse of vmap_pfn, vmap_pfn only allow none-page based
user invoke, i.e. PCIe BARs and other.

Signed-off-by: Huan Yang <link@vivo.com>
Reported-by: Bingbu Cao <bingbu.cao@linux.intel.com>
Closes: https://lore.kernel.org/dri-devel/eb7e0137-3508-4287-98c4-816c5fd98e10@vivo.com/T/#mbda4f64a3532b32e061f4e8763bc8e307bea3ca8
---
 drivers/dma-buf/Kconfig   |  1 -
 drivers/dma-buf/udmabuf.c | 22 +++++++---------------
 2 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index fee04fdb0822..b46eb8a552d7 100644
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -36,7 +36,6 @@ config UDMABUF
 	depends on DMA_SHARED_BUFFER
 	depends on MEMFD_CREATE || COMPILE_TEST
 	depends on MMU
-	select VMAP_PFN
 	help
 	  A driver to let userspace turn memfd regions into dma-bufs.
 	  Qemu can use this to create host dmabufs for guest framebuffers.
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 7eee3eb47a8e..79845565089d 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -109,29 +109,21 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma)
 static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map)
 {
 	struct udmabuf *ubuf = buf->priv;
-	unsigned long *pfns;
+	struct page **pages;
 	void *vaddr;
 	pgoff_t pg;
 
 	dma_resv_assert_held(buf->resv);
 
-	/**
-	 * HVO may free tail pages, so just use pfn to map each folio
-	 * into vmalloc area.
-	 */
-	pfns = kvmalloc_array(ubuf->pagecount, sizeof(*pfns), GFP_KERNEL);
-	if (!pfns)
+	pages = kvmalloc_array(ubuf->pagecount, sizeof(*pages), GFP_KERNEL);
+	if (!pages)
 		return -ENOMEM;
 
-	for (pg = 0; pg < ubuf->pagecount; pg++) {
-		unsigned long pfn = folio_pfn(ubuf->folios[pg]);
-
-		pfn += ubuf->offsets[pg] >> PAGE_SHIFT;
-		pfns[pg] = pfn;
-	}
+	for (pg = 0; pg < ubuf->pagecount; pg++)
+		pages[pg] = &ubuf->folios[pg]->page;
 
-	vaddr = vmap_pfn(pfns, ubuf->pagecount, PAGE_KERNEL);
-	kvfree(pfns);
+	vaddr = vm_map_ram(pages, ubuf->pagecount, -1);
+	kvfree(pages);
 	if (!vaddr)
 		return -EINVAL;
 
-- 
2.48.1
RE: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
Posted by Kasireddy, Vivek 8 months ago 
Hi Huan,

> Subject: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
> 
> This reverts commit 18d7de823b7150344d242c3677e65d68c5271b04.
> 
> This given a misuse of vmap_pfn, vmap_pfn only allow none-page based
> user invoke, i.e. PCIe BARs and other.
The commit message can be improved a little bit to briefly explain why vmap_pfn()
would not work for this use-case.

Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>

Thanks,
Vivek

> 
> Signed-off-by: Huan Yang <link@vivo.com>
> Reported-by: Bingbu Cao <bingbu.cao@linux.intel.com>
> Closes: https://lore.kernel.org/dri-devel/eb7e0137-3508-4287-98c4-
> 816c5fd98e10@vivo.com/T/#mbda4f64a3532b32e061f4e8763bc8e307bea3ca
> 8
> ---
>  drivers/dma-buf/Kconfig   |  1 -
>  drivers/dma-buf/udmabuf.c | 22 +++++++---------------
>  2 files changed, 7 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
> index fee04fdb0822..b46eb8a552d7 100644
> --- a/drivers/dma-buf/Kconfig
> +++ b/drivers/dma-buf/Kconfig
> @@ -36,7 +36,6 @@ config UDMABUF
>  	depends on DMA_SHARED_BUFFER
>  	depends on MEMFD_CREATE || COMPILE_TEST
>  	depends on MMU
> -	select VMAP_PFN
>  	help
>  	  A driver to let userspace turn memfd regions into dma-bufs.
>  	  Qemu can use this to create host dmabufs for guest framebuffers.
> diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
> index 7eee3eb47a8e..79845565089d 100644
> --- a/drivers/dma-buf/udmabuf.c
> +++ b/drivers/dma-buf/udmabuf.c
> @@ -109,29 +109,21 @@ static int mmap_udmabuf(struct dma_buf *buf,
> struct vm_area_struct *vma)
>  static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map)
>  {
>  	struct udmabuf *ubuf = buf->priv;
> -	unsigned long *pfns;
> +	struct page **pages;
>  	void *vaddr;
>  	pgoff_t pg;
> 
>  	dma_resv_assert_held(buf->resv);
> 
> -	/**
> -	 * HVO may free tail pages, so just use pfn to map each folio
> -	 * into vmalloc area.
> -	 */
> -	pfns = kvmalloc_array(ubuf->pagecount, sizeof(*pfns), GFP_KERNEL);
> -	if (!pfns)
> +	pages = kvmalloc_array(ubuf->pagecount, sizeof(*pages),
> GFP_KERNEL);
> +	if (!pages)
>  		return -ENOMEM;
> 
> -	for (pg = 0; pg < ubuf->pagecount; pg++) {
> -		unsigned long pfn = folio_pfn(ubuf->folios[pg]);
> -
> -		pfn += ubuf->offsets[pg] >> PAGE_SHIFT;
> -		pfns[pg] = pfn;
> -	}
> +	for (pg = 0; pg < ubuf->pagecount; pg++)
> +		pages[pg] = &ubuf->folios[pg]->page;
> 
> -	vaddr = vmap_pfn(pfns, ubuf->pagecount, PAGE_KERNEL);
> -	kvfree(pfns);
> +	vaddr = vm_map_ram(pages, ubuf->pagecount, -1);
> +	kvfree(pages);
>  	if (!vaddr)
>  		return -EINVAL;
> 
> --
> 2.48.1
Re: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
Posted by Huan Yang 8 months ago 
Hi Vivek,

Thanks for your ack.

在 2025/4/22 13:14, Kasireddy, Vivek 写道:
> Hi Huan,
>
>> Subject: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
>>
>> This reverts commit 18d7de823b7150344d242c3677e65d68c5271b04.
>>
>> This given a misuse of vmap_pfn, vmap_pfn only allow none-page based
>> user invoke, i.e. PCIe BARs and other.
> The commit message can be improved a little bit to briefly explain why vmap_pfn()
> would not work for this use-case.

OK, I will update patch direct in later reply.:)

Thanks,

Huan

>
> Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
>
> Thanks,
> Vivek
>
>> Signed-off-by: Huan Yang <link@vivo.com>
>> Reported-by: Bingbu Cao <bingbu.cao@linux.intel.com>
>> Closes: https://lore.kernel.org/dri-devel/eb7e0137-3508-4287-98c4-
>> 816c5fd98e10@vivo.com/T/#mbda4f64a3532b32e061f4e8763bc8e307bea3ca
>> 8
>> ---
>>   drivers/dma-buf/Kconfig   |  1 -
>>   drivers/dma-buf/udmabuf.c | 22 +++++++---------------
>>   2 files changed, 7 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
>> index fee04fdb0822..b46eb8a552d7 100644
>> --- a/drivers/dma-buf/Kconfig
>> +++ b/drivers/dma-buf/Kconfig
>> @@ -36,7 +36,6 @@ config UDMABUF
>>   	depends on DMA_SHARED_BUFFER
>>   	depends on MEMFD_CREATE || COMPILE_TEST
>>   	depends on MMU
>> -	select VMAP_PFN
>>   	help
>>   	  A driver to let userspace turn memfd regions into dma-bufs.
>>   	  Qemu can use this to create host dmabufs for guest framebuffers.
>> diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
>> index 7eee3eb47a8e..79845565089d 100644
>> --- a/drivers/dma-buf/udmabuf.c
>> +++ b/drivers/dma-buf/udmabuf.c
>> @@ -109,29 +109,21 @@ static int mmap_udmabuf(struct dma_buf *buf,
>> struct vm_area_struct *vma)
>>   static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map)
>>   {
>>   	struct udmabuf *ubuf = buf->priv;
>> -	unsigned long *pfns;
>> +	struct page **pages;
>>   	void *vaddr;
>>   	pgoff_t pg;
>>
>>   	dma_resv_assert_held(buf->resv);
>>
>> -	/**
>> -	 * HVO may free tail pages, so just use pfn to map each folio
>> -	 * into vmalloc area.
>> -	 */
>> -	pfns = kvmalloc_array(ubuf->pagecount, sizeof(*pfns), GFP_KERNEL);
>> -	if (!pfns)
>> +	pages = kvmalloc_array(ubuf->pagecount, sizeof(*pages),
>> GFP_KERNEL);
>> +	if (!pages)
>>   		return -ENOMEM;
>>
>> -	for (pg = 0; pg < ubuf->pagecount; pg++) {
>> -		unsigned long pfn = folio_pfn(ubuf->folios[pg]);
>> -
>> -		pfn += ubuf->offsets[pg] >> PAGE_SHIFT;
>> -		pfns[pg] = pfn;
>> -	}
>> +	for (pg = 0; pg < ubuf->pagecount; pg++)
>> +		pages[pg] = &ubuf->folios[pg]->page;
>>
>> -	vaddr = vmap_pfn(pfns, ubuf->pagecount, PAGE_KERNEL);
>> -	kvfree(pfns);
>> +	vaddr = vm_map_ram(pages, ubuf->pagecount, -1);
>> +	kvfree(pages);
>>   	if (!vaddr)
>>   		return -EINVAL;
>>
>> --
>> 2.48.1
Re: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
Posted by Huan Yang 8 months ago 
 From 38aa11d92f209e7529736f3e11e08dfc804bdfae Mon Sep 17 00:00:00 2001
From: Huan Yang <link@vivo.com>
Date: Tue, 15 Apr 2025 10:04:18 +0800
Subject: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"

This reverts commit 18d7de823b7150344d242c3677e65d68c5271b04.

This given a misuse of vmap_pfn, vmap_pfn give a !pfn_valid check
to avoid user miss use it. This API design to only for none-page struct
based user invoke, i.e. PCIe BARs and other. So any page based will
inject by !pfn_valid check.

udmabuf used shmem or hugetlb as folio src, hence, page/folio based,
can't use it.

Signed-off-by: Huan Yang <link@vivo.com>
Reported-by: Bingbu Cao <bingbu.cao@linux.intel.com>
Closes: https://lore.kernel.org/dri-devel/eb7e0137-3508-4287-98c4-816c5fd98e10@vivo.com/T/#mbda4f64a3532b32e061f4e8763bc8e307bea3ca8
Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
---
  drivers/dma-buf/Kconfig   |  1 -
  drivers/dma-buf/udmabuf.c | 22 +++++++---------------
  2 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index fee04fdb0822..b46eb8a552d7 100644
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -36,7 +36,6 @@ config UDMABUF
      depends on DMA_SHARED_BUFFER
      depends on MEMFD_CREATE || COMPILE_TEST
      depends on MMU
-    select VMAP_PFN
      help
        A driver to let userspace turn memfd regions into dma-bufs.
        Qemu can use this to create host dmabufs for guest framebuffers.
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 7eee3eb47a8e..79845565089d 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -109,29 +109,21 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma)
  static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map)
  {
      struct udmabuf *ubuf = buf->priv;
-    unsigned long *pfns;
+    struct page **pages;
      void *vaddr;
      pgoff_t pg;

      dma_resv_assert_held(buf->resv);

-    /**
-     * HVO may free tail pages, so just use pfn to map each folio
-     * into vmalloc area.
-     */
-    pfns = kvmalloc_array(ubuf->pagecount, sizeof(*pfns), GFP_KERNEL);
-    if (!pfns)
+    pages = kvmalloc_array(ubuf->pagecount, sizeof(*pages), GFP_KERNEL);
+    if (!pages)
          return -ENOMEM;

-    for (pg = 0; pg < ubuf->pagecount; pg++) {
-        unsigned long pfn = folio_pfn(ubuf->folios[pg]);
-
-        pfn += ubuf->offsets[pg] >> PAGE_SHIFT;
-        pfns[pg] = pfn;
-    }
+    for (pg = 0; pg < ubuf->pagecount; pg++)
+        pages[pg] = &ubuf->folios[pg]->page;

-    vaddr = vmap_pfn(pfns, ubuf->pagecount, PAGE_KERNEL);
-    kvfree(pfns);
+    vaddr = vm_map_ram(pages, ubuf->pagecount, -1);
+    kvfree(pages);
      if (!vaddr)
          return -EINVAL;

--
2.48.1
RE: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
Posted by Kasireddy, Vivek 7 months, 3 weeks ago 
Hi Huan,

> Subject: Re: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
> 
>  From 38aa11d92f209e7529736f3e11e08dfc804bdfae Mon Sep 17 00:00:00
> 2001
> From: Huan Yang <link@vivo.com>
> Date: Tue, 15 Apr 2025 10:04:18 +0800
> Subject: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
> 
> This reverts commit 18d7de823b7150344d242c3677e65d68c5271b04.
> 
> This given a misuse of vmap_pfn, vmap_pfn give a !pfn_valid check
> to avoid user miss use it. This API design to only for none-page struct
> based user invoke, i.e. PCIe BARs and other. So any page based will
> inject by !pfn_valid check.
> 
> udmabuf used shmem or hugetlb as folio src, hence, page/folio based,
> can't use it.
Please consider having a commit message like below and resend both patches:
"We cannot use vmap_pfn() in vmap_udmabuf() as it would fail the pfn_valid()
check in vmap_pfn_apply(). This is because vmap_pfn() is intended to be
used for mapping non-struct-page memory such as PCIe BARs. Since, udmabuf
mostly works with pages/folios backed by shmem/hugetlbfs/THP, vmap_pfn()
is not the right tool or API to invoke for implementing vmap."

Thanks,
Vivek

> 
> Signed-off-by: Huan Yang <link@vivo.com>
> Reported-by: Bingbu Cao <bingbu.cao@linux.intel.com>
> Closes: https://lore.kernel.org/dri-devel/eb7e0137-3508-4287-98c4-
> 816c5fd98e10@vivo.com/T/#mbda4f64a3532b32e061f4e8763bc8e307bea3ca
> 8
> Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
> ---
>   drivers/dma-buf/Kconfig   |  1 -
>   drivers/dma-buf/udmabuf.c | 22 +++++++---------------
>   2 files changed, 7 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
> index fee04fdb0822..b46eb8a552d7 100644
> --- a/drivers/dma-buf/Kconfig
> +++ b/drivers/dma-buf/Kconfig
> @@ -36,7 +36,6 @@ config UDMABUF
>       depends on DMA_SHARED_BUFFER
>       depends on MEMFD_CREATE || COMPILE_TEST
>       depends on MMU
> -    select VMAP_PFN
>       help
>         A driver to let userspace turn memfd regions into dma-bufs.
>         Qemu can use this to create host dmabufs for guest framebuffers.
> diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
> index 7eee3eb47a8e..79845565089d 100644
> --- a/drivers/dma-buf/udmabuf.c
> +++ b/drivers/dma-buf/udmabuf.c
> @@ -109,29 +109,21 @@ static int mmap_udmabuf(struct dma_buf *buf,
> struct vm_area_struct *vma)
>   static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map)
>   {
>       struct udmabuf *ubuf = buf->priv;
> -    unsigned long *pfns;
> +    struct page **pages;
>       void *vaddr;
>       pgoff_t pg;
> 
>       dma_resv_assert_held(buf->resv);
> 
> -    /**
> -     * HVO may free tail pages, so just use pfn to map each folio
> -     * into vmalloc area.
> -     */
> -    pfns = kvmalloc_array(ubuf->pagecount, sizeof(*pfns), GFP_KERNEL);
> -    if (!pfns)
> +    pages = kvmalloc_array(ubuf->pagecount, sizeof(*pages), GFP_KERNEL);
> +    if (!pages)
>           return -ENOMEM;
> 
> -    for (pg = 0; pg < ubuf->pagecount; pg++) {
> -        unsigned long pfn = folio_pfn(ubuf->folios[pg]);
> -
> -        pfn += ubuf->offsets[pg] >> PAGE_SHIFT;
> -        pfns[pg] = pfn;
> -    }
> +    for (pg = 0; pg < ubuf->pagecount; pg++)
> +        pages[pg] = &ubuf->folios[pg]->page;
> 
> -    vaddr = vmap_pfn(pfns, ubuf->pagecount, PAGE_KERNEL);
> -    kvfree(pfns);
> +    vaddr = vm_map_ram(pages, ubuf->pagecount, -1);
> +    kvfree(pages);
>       if (!vaddr)
>           return -EINVAL;
> 
> --
> 2.48.1
>
Re: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
Posted by Huan Yang 7 months, 3 weeks ago 
在 2025/4/28 12:16, Kasireddy, Vivek 写道:
> Hi Huan,
>
>> Subject: Re: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
>>
>>   From 38aa11d92f209e7529736f3e11e08dfc804bdfae Mon Sep 17 00:00:00
>> 2001
>> From: Huan Yang <link@vivo.com>
>> Date: Tue, 15 Apr 2025 10:04:18 +0800
>> Subject: [PATCH 1/2] Revert "udmabuf: fix vmap_udmabuf error page set"
>>
>> This reverts commit 18d7de823b7150344d242c3677e65d68c5271b04.
>>
>> This given a misuse of vmap_pfn, vmap_pfn give a !pfn_valid check
>> to avoid user miss use it. This API design to only for none-page struct
>> based user invoke, i.e. PCIe BARs and other. So any page based will
>> inject by !pfn_valid check.
>>
>> udmabuf used shmem or hugetlb as folio src, hence, page/folio based,
>> can't use it.
> Please consider having a commit message like below and resend both patches:
> "We cannot use vmap_pfn() in vmap_udmabuf() as it would fail the pfn_valid()
> check in vmap_pfn_apply(). This is because vmap_pfn() is intended to be
> used for mapping non-struct-page memory such as PCIe BARs. Since, udmabuf
> mostly works with pages/folios backed by shmem/hugetlbfs/THP, vmap_pfn()
> is not the right tool or API to invoke for implementing vmap."

Thanks, that's clearer, I'll update in v2 version. :)

Huan

>
> Thanks,
> Vivek
>
>> Signed-off-by: Huan Yang <link@vivo.com>
>> Reported-by: Bingbu Cao <bingbu.cao@linux.intel.com>
>> Closes: https://lore.kernel.org/dri-devel/eb7e0137-3508-4287-98c4-
>> 816c5fd98e10@vivo.com/T/#mbda4f64a3532b32e061f4e8763bc8e307bea3ca
>> 8
>> Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
>> ---
>>    drivers/dma-buf/Kconfig   |  1 -
>>    drivers/dma-buf/udmabuf.c | 22 +++++++---------------
>>    2 files changed, 7 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
>> index fee04fdb0822..b46eb8a552d7 100644
>> --- a/drivers/dma-buf/Kconfig
>> +++ b/drivers/dma-buf/Kconfig
>> @@ -36,7 +36,6 @@ config UDMABUF
>>        depends on DMA_SHARED_BUFFER
>>        depends on MEMFD_CREATE || COMPILE_TEST
>>        depends on MMU
>> -    select VMAP_PFN
>>        help
>>          A driver to let userspace turn memfd regions into dma-bufs.
>>          Qemu can use this to create host dmabufs for guest framebuffers.
>> diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
>> index 7eee3eb47a8e..79845565089d 100644
>> --- a/drivers/dma-buf/udmabuf.c
>> +++ b/drivers/dma-buf/udmabuf.c
>> @@ -109,29 +109,21 @@ static int mmap_udmabuf(struct dma_buf *buf,
>> struct vm_area_struct *vma)
>>    static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map)
>>    {
>>        struct udmabuf *ubuf = buf->priv;
>> -    unsigned long *pfns;
>> +    struct page **pages;
>>        void *vaddr;
>>        pgoff_t pg;
>>
>>        dma_resv_assert_held(buf->resv);
>>
>> -    /**
>> -     * HVO may free tail pages, so just use pfn to map each folio
>> -     * into vmalloc area.
>> -     */
>> -    pfns = kvmalloc_array(ubuf->pagecount, sizeof(*pfns), GFP_KERNEL);
>> -    if (!pfns)
>> +    pages = kvmalloc_array(ubuf->pagecount, sizeof(*pages), GFP_KERNEL);
>> +    if (!pages)
>>            return -ENOMEM;
>>
>> -    for (pg = 0; pg < ubuf->pagecount; pg++) {
>> -        unsigned long pfn = folio_pfn(ubuf->folios[pg]);
>> -
>> -        pfn += ubuf->offsets[pg] >> PAGE_SHIFT;
>> -        pfns[pg] = pfn;
>> -    }
>> +    for (pg = 0; pg < ubuf->pagecount; pg++)
>> +        pages[pg] = &ubuf->folios[pg]->page;
>>
>> -    vaddr = vmap_pfn(pfns, ubuf->pagecount, PAGE_KERNEL);
>> -    kvfree(pfns);
>> +    vaddr = vm_map_ram(pages, ubuf->pagecount, -1);
>> +    kvfree(pages);
>>        if (!vaddr)
>>            return -EINVAL;
>>
>> --
>> 2.48.1
>>

Patchew 2.1-devel-b67e4c2

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