generate_test_data() acquires a page with alloc_page(GFP_KERNEL).
The GFP_KERNEL is typical for kernel-internal allocations.
The caller requires ZONE_NORMAL or a lower zone for direct access.
Therefore the page cannot come from ZONE_HIGHMEM. Thus there's
no need to map it with kmap().
Also, the kmap() is being deprecated in favor of kmap_local_page() [1].
Hence, use a plain page_address() directly.
Since the page passed to the page_address() is not from the highmem
zone, the page_address() function will always return a valid kernel
virtual address and will not return NULL. Hence, remove the check
'if (!ptr)'.
Remove the unused variable 'ptr' and label 'err_free_page'.
[1]: https://lore.kernel.org/all/[email protected]/
Suggested-by: Fabio M. De Francesco <[email protected]>
Signed-off-by: Sumitra Sharma <[email protected]>
---
- Link to v1: https://lore.kernel.org/bpf/[email protected]/T/
- Link to v2: https://lore.kernel.org/all/[email protected]/
- Link to v3: https://lore.kernel.org/all/[email protected]/
Changes in v4:
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
- Remove unused label 'err_free_page'.
Changes in v3:
Noted by: Fabio M. De Francesco<[email protected]>
- Remove the check 'if (!ptr)'.
- Remove the unused variable 'ptr'.
- Change the commit message.
Changes in v2:
Noted by: Fabio M. De Francesco<[email protected]>
- Remove the kmap() call and call page_address() instead.
- Change the commit subject and message.
lib/test_bpf.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index ade9ac672adb..a5cc5f9fc4e8 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -14381,25 +14381,17 @@ static void *generate_test_data(struct bpf_test *test, int sub)
* single fragment to the skb, filled with
* test->frag_data.
*/
- void *ptr;
-
page = alloc_page(GFP_KERNEL);
if (!page)
goto err_kfree_skb;
- ptr = kmap(page);
- if (!ptr)
- goto err_free_page;
- memcpy(ptr, test->frag_data, MAX_DATA);
- kunmap(page);
+ memcpy(page_address(page), test->frag_data, MAX_DATA);
skb_add_rx_frag(skb, 0, page, 0, MAX_DATA, MAX_DATA);
}
return skb;
-err_free_page:
- __free_page(page);
err_kfree_skb:
kfree_skb(skb);
return NULL;
--
2.25.1
On venerd? 23 giugno 2023 17:16:44 CEST Sumitra Sharma wrote:
> generate_test_data() acquires a page with alloc_page(GFP_KERNEL).
> The GFP_KERNEL is typical for kernel-internal allocations.
> The caller requires ZONE_NORMAL or a lower zone for direct access.
>
> Therefore the page cannot come from ZONE_HIGHMEM. Thus there's
> no need to map it with kmap().
>
> Also, the kmap() is being deprecated in favor of kmap_local_page() [1].
>
> Hence, use a plain page_address() directly.
>
> Since the page passed to the page_address() is not from the highmem
> zone, the page_address() function will always return a valid kernel
> virtual address and will not return NULL. Hence, remove the check
> 'if (!ptr)'.
>
> Remove the unused variable 'ptr' and label 'err_free_page'.
>
> [1]: https://lore.kernel.org/all/[email protected]/
>
> Suggested-by: Fabio M. De Francesco <[email protected]>
I can't see no more things that prevent my tag, then it is...
Reviewed-by: Fabio M. De Francesco <[email protected]>
Thanks for working on it for all the time it took to get to v4 and for
listening to what you've been suggested to change.
Well done :-)
Fabio
> Signed-off-by: Sumitra Sharma <[email protected]>
> ---
>
> - Link to v1:
> https://lore.kernel.org/bpf/[email protected]/T/ - Link to
> v2: https://lore.kernel.org/all/[email protected]/ - Link
> to v3: https://lore.kernel.org/all/[email protected]/
>
> Changes in v4:
> Reported-by: kernel test robot <[email protected]>
> Closes:
> https://lore.kernel.org/oe-kbuild-all/[email protected]/ -
> Remove unused label 'err_free_page'.
>
> Changes in v3:
> Noted by: Fabio M. De Francesco<[email protected]>
> - Remove the check 'if (!ptr)'.
> - Remove the unused variable 'ptr'.
> - Change the commit message.
>
> Changes in v2:
> Noted by: Fabio M. De Francesco<[email protected]>
> - Remove the kmap() call and call page_address() instead.
> - Change the commit subject and message.
>
> lib/test_bpf.c | 10 +---------
> 1 file changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/lib/test_bpf.c b/lib/test_bpf.c
> index ade9ac672adb..a5cc5f9fc4e8 100644
> --- a/lib/test_bpf.c
> +++ b/lib/test_bpf.c
> @@ -14381,25 +14381,17 @@ static void *generate_test_data(struct bpf_test
> *test, int sub) * single fragment to the skb, filled with
> * test->frag_data.
> */
> - void *ptr;
> -
> page = alloc_page(GFP_KERNEL);
>
> if (!page)
> goto err_kfree_skb;
>
> - ptr = kmap(page);
> - if (!ptr)
> - goto err_free_page;
> - memcpy(ptr, test->frag_data, MAX_DATA);
> - kunmap(page);
> + memcpy(page_address(page), test->frag_data, MAX_DATA);
> skb_add_rx_frag(skb, 0, page, 0, MAX_DATA, MAX_DATA);
> }
>
> return skb;
>
> -err_free_page:
> - __free_page(page);
> err_kfree_skb:
> kfree_skb(skb);
> return NULL;
> --
> 2.25.1
Sumitra Sharma wrote:
> generate_test_data() acquires a page with alloc_page(GFP_KERNEL).
> The GFP_KERNEL is typical for kernel-internal allocations.
> The caller requires ZONE_NORMAL or a lower zone for direct access.
>
> Therefore the page cannot come from ZONE_HIGHMEM. Thus there's
> no need to map it with kmap().
>
> Also, the kmap() is being deprecated in favor of kmap_local_page() [1].
>
> Hence, use a plain page_address() directly.
>
> Since the page passed to the page_address() is not from the highmem
> zone, the page_address() function will always return a valid kernel
> virtual address and will not return NULL. Hence, remove the check
> 'if (!ptr)'.
>
> Remove the unused variable 'ptr' and label 'err_free_page'.
>
> [1]: https://lore.kernel.org/all/[email protected]/
>
> Suggested-by: Fabio M. De Francesco <[email protected]>
> Signed-off-by: Sumitra Sharma <[email protected]>
Just saw the report from kernel bot...
Better on this version than I saw before! :-D
Reviewed-by: Ira Weiny <[email protected]>
> ---
>
> - Link to v1: https://lore.kernel.org/bpf/[email protected]/T/
> - Link to v2: https://lore.kernel.org/all/[email protected]/
> - Link to v3: https://lore.kernel.org/all/[email protected]/
>
> Changes in v4:
> Reported-by: kernel test robot <[email protected]>
> Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
> - Remove unused label 'err_free_page'.
>
> Changes in v3:
> Noted by: Fabio M. De Francesco<[email protected]>
> - Remove the check 'if (!ptr)'.
> - Remove the unused variable 'ptr'.
> - Change the commit message.
>
> Changes in v2:
> Noted by: Fabio M. De Francesco<[email protected]>
> - Remove the kmap() call and call page_address() instead.
> - Change the commit subject and message.
>
> lib/test_bpf.c | 10 +---------
> 1 file changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/lib/test_bpf.c b/lib/test_bpf.c
> index ade9ac672adb..a5cc5f9fc4e8 100644
> --- a/lib/test_bpf.c
> +++ b/lib/test_bpf.c
> @@ -14381,25 +14381,17 @@ static void *generate_test_data(struct bpf_test *test, int sub)
> * single fragment to the skb, filled with
> * test->frag_data.
> */
> - void *ptr;
> -
> page = alloc_page(GFP_KERNEL);
>
> if (!page)
> goto err_kfree_skb;
>
> - ptr = kmap(page);
> - if (!ptr)
> - goto err_free_page;
> - memcpy(ptr, test->frag_data, MAX_DATA);
> - kunmap(page);
> + memcpy(page_address(page), test->frag_data, MAX_DATA);
> skb_add_rx_frag(skb, 0, page, 0, MAX_DATA, MAX_DATA);
> }
>
> return skb;
>
> -err_free_page:
> - __free_page(page);
> err_kfree_skb:
> kfree_skb(skb);
> return NULL;
> --
> 2.25.1
>
On Mon, Jun 26, 2023 at 03:07:22PM +0200, Fabio M. De Francesco wrote:
> On venerd? 23 giugno 2023 17:16:44 CEST Sumitra Sharma wrote:
> > generate_test_data() acquires a page with alloc_page(GFP_KERNEL).
> > The GFP_KERNEL is typical for kernel-internal allocations.
> > The caller requires ZONE_NORMAL or a lower zone for direct access.
> >
> > Therefore the page cannot come from ZONE_HIGHMEM. Thus there's
> > no need to map it with kmap().
> >
> > Also, the kmap() is being deprecated in favor of kmap_local_page() [1].
> >
> > Hence, use a plain page_address() directly.
> >
> > Since the page passed to the page_address() is not from the highmem
> > zone, the page_address() function will always return a valid kernel
> > virtual address and will not return NULL. Hence, remove the check
> > 'if (!ptr)'.
> >
> > Remove the unused variable 'ptr' and label 'err_free_page'.
> >
> > [1]: https://lore.kernel.org/all/[email protected]/
> >
> > Suggested-by: Fabio M. De Francesco <[email protected]>
>
> I can't see no more things that prevent my tag, then it is...
>
> Reviewed-by: Fabio M. De Francesco <[email protected]>
>
> Thanks for working on it for all the time it took to get to v4 and for
> listening to what you've been suggested to change.
>
> Well done :-)
Thank you, Fabio and Ira, for your tags and kind words :)
Thanks & regards
Sumitra
>
> Fabio
>
> > Signed-off-by: Sumitra Sharma <[email protected]>
> > ---
> >
> > - Link to v1:
> > https://lore.kernel.org/bpf/[email protected]/T/ - Link to
> > v2: https://lore.kernel.org/all/[email protected]/ - Link
> > to v3: https://lore.kernel.org/all/[email protected]/
> >
> > Changes in v4:
> > Reported-by: kernel test robot <[email protected]>
> > Closes:
> > https://lore.kernel.org/oe-kbuild-all/[email protected]/ -
> > Remove unused label 'err_free_page'.
> >
> > Changes in v3:
> > Noted by: Fabio M. De Francesco<[email protected]>
> > - Remove the check 'if (!ptr)'.
> > - Remove the unused variable 'ptr'.
> > - Change the commit message.
> >
> > Changes in v2:
> > Noted by: Fabio M. De Francesco<[email protected]>
> > - Remove the kmap() call and call page_address() instead.
> > - Change the commit subject and message.
> >
> > lib/test_bpf.c | 10 +---------
> > 1 file changed, 1 insertion(+), 9 deletions(-)
> >
> > diff --git a/lib/test_bpf.c b/lib/test_bpf.c
> > index ade9ac672adb..a5cc5f9fc4e8 100644
> > --- a/lib/test_bpf.c
> > +++ b/lib/test_bpf.c
> > @@ -14381,25 +14381,17 @@ static void *generate_test_data(struct bpf_test
> > *test, int sub) * single fragment to the skb, filled with
> > * test->frag_data.
> > */
> > - void *ptr;
> > -
> > page = alloc_page(GFP_KERNEL);
> >
> > if (!page)
> > goto err_kfree_skb;
> >
> > - ptr = kmap(page);
> > - if (!ptr)
> > - goto err_free_page;
> > - memcpy(ptr, test->frag_data, MAX_DATA);
> > - kunmap(page);
> > + memcpy(page_address(page), test->frag_data, MAX_DATA);
> > skb_add_rx_frag(skb, 0, page, 0, MAX_DATA, MAX_DATA);
> > }
> >
> > return skb;
> >
> > -err_free_page:
> > - __free_page(page);
> > err_kfree_skb:
> > kfree_skb(skb);
> > return NULL;
> > --
> > 2.25.1
>
>
>
>
Hello:
This patch was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <[email protected]>:
On Fri, 23 Jun 2023 08:16:44 -0700 you wrote:
> generate_test_data() acquires a page with alloc_page(GFP_KERNEL).
> The GFP_KERNEL is typical for kernel-internal allocations.
> The caller requires ZONE_NORMAL or a lower zone for direct access.
>
> Therefore the page cannot come from ZONE_HIGHMEM. Thus there's
> no need to map it with kmap().
>
> [...]
Here is the summary with links:
- [v4] lib/test_bpf: Call page_address() on page acquired with GFP_KERNEL flag
https://git.kernel.org/bpf/bpf-next/c/da1a055d01ed
You are awesome, thank you!
--
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