diff mbox

[1/2] dax: hide block device code in #ifdef

Message ID 20170515134508.2713243-1-arnd@arndb.de (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Arnd Bergmann May 15, 2017, 1:44 p.m. UTC
We allow configurations with CONFIG_BLOCK=n and CONFIG_DAX=y, which now
results in a link error:

drivers/dax/super.c: In function 'bdev_dax_pgoff':
drivers/dax/super.c:50:26: error: implicit declaration of function 'get_start_sect'; did you mean 'get_task_cred'? [-Werror=implicit-function-declaration]

The two obvious ways to avoid the link error are to either add an #ifdef
around the code that was moved from fs/block_dev.c, or to disallow the
configuration. I could not see if there is or is not a reason to support
this combination of options, but in case there is, the #ifdef is the
safer choice.

Fixes: ef51042472f5 ("block, dax: move "select DAX" from BLOCK to FS_DAX")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/dax/super.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Dan Williams May 15, 2017, 2:11 p.m. UTC | #1
On Mon, May 15, 2017 at 6:44 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> We allow configurations with CONFIG_BLOCK=n and CONFIG_DAX=y, which now
> results in a link error:
>
> drivers/dax/super.c: In function 'bdev_dax_pgoff':
> drivers/dax/super.c:50:26: error: implicit declaration of function 'get_start_sect'; did you mean 'get_task_cred'? [-Werror=implicit-function-declaration]
>
> The two obvious ways to avoid the link error are to either add an #ifdef
> around the code that was moved from fs/block_dev.c, or to disallow the
> configuration. I could not see if there is or is not a reason to support
> this combination of options, but in case there is, the #ifdef is the
> safer choice.
>
> Fixes: ef51042472f5 ("block, dax: move "select DAX" from BLOCK to FS_DAX")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Yup, the same one I came up with:

https://patchwork.kernel.org/patch/9725513/

If you have a a pull request coming up soon you can add my Acked-by to
both of these patches, otherwise I'll send what I have along at the
end of the week.
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Arnd Bergmann May 15, 2017, 2:20 p.m. UTC | #2
On Mon, May 15, 2017 at 4:11 PM, Dan Williams <dan.j.williams@intel.com> wrote:
> On Mon, May 15, 2017 at 6:44 AM, Arnd Bergmann <arnd@arndb.de> wrote:
>> We allow configurations with CONFIG_BLOCK=n and CONFIG_DAX=y, which now
>> results in a link error:
>>
>> drivers/dax/super.c: In function 'bdev_dax_pgoff':
>> drivers/dax/super.c:50:26: error: implicit declaration of function 'get_start_sect'; did you mean 'get_task_cred'? [-Werror=implicit-function-declaration]
>>
>> The two obvious ways to avoid the link error are to either add an #ifdef
>> around the code that was moved from fs/block_dev.c, or to disallow the
>> configuration. I could not see if there is or is not a reason to support
>> this combination of options, but in case there is, the #ifdef is the
>> safer choice.
>>
>> Fixes: ef51042472f5 ("block, dax: move "select DAX" from BLOCK to FS_DAX")
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> Yup, the same one I came up with:
>
> https://patchwork.kernel.org/patch/9725513/
>
> If you have a a pull request coming up soon you can add my Acked-by to
> both of these patches, otherwise I'll send what I have along at the
> end of the week.

I didn't plan to send a pull request, please use whatever you have.

      Arnd
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Darrick J. Wong May 15, 2017, 3:50 p.m. UTC | #3
On Mon, May 15, 2017 at 04:20:09PM +0200, Arnd Bergmann wrote:
> On Mon, May 15, 2017 at 4:11 PM, Dan Williams <dan.j.williams@intel.com> wrote:
> > On Mon, May 15, 2017 at 6:44 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> >> We allow configurations with CONFIG_BLOCK=n and CONFIG_DAX=y, which now
> >> results in a link error:
> >>
> >> drivers/dax/super.c: In function 'bdev_dax_pgoff':
> >> drivers/dax/super.c:50:26: error: implicit declaration of function 'get_start_sect'; did you mean 'get_task_cred'? [-Werror=implicit-function-declaration]
> >>
> >> The two obvious ways to avoid the link error are to either add an #ifdef
> >> around the code that was moved from fs/block_dev.c, or to disallow the
> >> configuration. I could not see if there is or is not a reason to support
> >> this combination of options, but in case there is, the #ifdef is the
> >> safer choice.
> >>
> >> Fixes: ef51042472f5 ("block, dax: move "select DAX" from BLOCK to FS_DAX")
> >> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> >
> > Yup, the same one I came up with:
> >
> > https://patchwork.kernel.org/patch/9725513/
> >
> > If you have a a pull request coming up soon you can add my Acked-by to
> > both of these patches, otherwise I'll send what I have along at the
> > end of the week.
> 
> I didn't plan to send a pull request, please use whatever you have.

I don't mind pulling the (second) patch in via the xfs tree.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> 
>       Arnd
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Arnd Bergmann May 16, 2017, 11:16 a.m. UTC | #4
On Mon, May 15, 2017 at 5:50 PM, Darrick J. Wong
<darrick.wong@oracle.com> wrote:
> On Mon, May 15, 2017 at 04:20:09PM +0200, Arnd Bergmann wrote:
>> On Mon, May 15, 2017 at 4:11 PM, Dan Williams <dan.j.williams@intel.com> wrote:
>> > On Mon, May 15, 2017 at 6:44 AM, Arnd Bergmann <arnd@arndb.de> wrote:
>> >> We allow configurations with CONFIG_BLOCK=n and CONFIG_DAX=y, which now
>> >> results in a link error:
>> >>
>> >> drivers/dax/super.c: In function 'bdev_dax_pgoff':
>> >> drivers/dax/super.c:50:26: error: implicit declaration of function 'get_start_sect'; did you mean 'get_task_cred'? [-Werror=implicit-function-declaration]
>> >>
>> >> The two obvious ways to avoid the link error are to either add an #ifdef
>> >> around the code that was moved from fs/block_dev.c, or to disallow the
>> >> configuration. I could not see if there is or is not a reason to support
>> >> this combination of options, but in case there is, the #ifdef is the
>> >> safer choice.
>> >>
>> >> Fixes: ef51042472f5 ("block, dax: move "select DAX" from BLOCK to FS_DAX")
>> >> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>> >
>> > Yup, the same one I came up with:
>> >
>> > https://patchwork.kernel.org/patch/9725513/
>> >
>> > If you have a a pull request coming up soon you can add my Acked-by to
>> > both of these patches, otherwise I'll send what I have along at the
>> > end of the week.
>>
>> I didn't plan to send a pull request, please use whatever you have.
>
> I don't mind pulling the (second) patch in via the xfs tree.
>
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
>

I think Dan's "dax, xfs, ext4: compile out iomap-dax paths in the
FS_DAX=n case" handles this in a nicer way, so my patch 2/2 is not
needed any more.

      Arnd
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diff mbox

Patch

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index ebf43f531ada..6ed32aac8bbe 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -44,6 +44,7 @@  void dax_read_unlock(int id)
 }
 EXPORT_SYMBOL_GPL(dax_read_unlock);
 
+#ifdef CONFIG_BLOCK
 int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,
 		pgoff_t *pgoff)
 {
@@ -112,6 +113,7 @@  int __bdev_dax_supported(struct super_block *sb, int blocksize)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(__bdev_dax_supported);
+#endif
 
 /**
  * struct dax_device - anchor object for dax services