Re: [PATCH v9 03/11] configure: check for sys/disk.h

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 1/26/21 6:55 AM, Joelle van Dyne wrote:
> Previously, the only case where sys/disk.h does not exist is on
> platforms that define __DragonFly__. However, iOS also does not have
> this header. Previously, I had it as
> 
> #if defined(__DragonFly__) || defined(CONFIG_IOS)
> 
> But there was a code review comment that we should use feature flags
> instead of platform defines. So I added the HAS_SYS_DISK_H flag.

On technical lists, it's best to avoid top-posting, and to
instead reply inline to make the conversation easier to follow.

> 
> -j
> 
> On Mon, Jan 25, 2021 at 8:35 PM Warner Losh <imp@bsdimp.com> wrote:
>>
>>
>>
>> On Mon, Jan 25, 2021 at 6:33 PM Joelle van Dyne <j@getutm.app> wrote:
>>>
>>> Some BSD platforms do not have this header.
>>>
>>> Signed-off-by: Joelle van Dyne <j@getutm.app>
>>> ---
>>>  meson.build        | 1 +
>>>  block.c            | 2 +-
>>>  block/file-posix.c | 2 +-
>>>  3 files changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/meson.build b/meson.build
>>> index 27110075df..6818d97df5 100644
>>> --- a/meson.build
>>> +++ b/meson.build
>>> @@ -1117,6 +1117,7 @@ config_host_data.set('HAVE_PTY_H', cc.has_header('pty.h'))
>>>  config_host_data.set('HAVE_SYS_IOCCOM_H', cc.has_header('sys/ioccom.h'))
>>>  config_host_data.set('HAVE_SYS_KCOV_H', cc.has_header('sys/kcov.h'))
>>>  config_host_data.set('HAVE_HOST_BLOCK_DEVICE', have_host_block_device)
>>> +config_host_data.set('HAVE_SYS_DISK_H', cc.has_header('sys/disk.h'))
>>>
>>>  ignored = ['CONFIG_QEMU_INTERP_PREFIX'] # actually per-target
>>>  arrays = ['CONFIG_AUDIO_DRIVERS', 'CONFIG_BDRV_RW_WHITELIST', 'CONFIG_BDRV_RO_WHITELIST']
>>> diff --git a/block.c b/block.c
>>> index 8b9d457546..c4cf391dea 100644
>>> --- a/block.c
>>> +++ b/block.c
>>> @@ -54,7 +54,7 @@
>>>  #ifdef CONFIG_BSD
>>>  #include <sys/ioctl.h>
>>>  #include <sys/queue.h>
>>> -#ifndef __DragonFly__
>>> +#if defined(HAVE_SYS_DISK_H)
>>>  #include <sys/disk.h>
>>>  #endif
>>>  #endif
>>> diff --git a/block/file-posix.c b/block/file-posix.c
>>> index 11d2021346..666d3e7504 100644
>>> --- a/block/file-posix.c
>>> +++ b/block/file-posix.c
>>> @@ -2320,7 +2320,7 @@ again:
>>>          }
>>>          if (size == 0)
>>>  #endif
>>> -#if defined(__APPLE__) && defined(__MACH__)
>>> +#if defined(HAVE_SYS_DISK_H) && defined(__APPLE__) && defined(__MACH__)
>>
>>
>> Why is this needed? __DragonFly__ doesn't define either __APPLE__ or __MACH__

Hmm we could also add:

  config_host_data.set('HAVE_DKIOCGETBLOCKCOUNT', cc.compiles(...))

Then this block would be easier to read:

  #if defined(HAVE_DKIOCGETBLOCKCOUNT)
  ...

(Maybe this is what Warner meant?)

>>
>> Warner
>>
>>>
>>>          {
>>>              uint64_t sectors = 0;
>>>              uint32_t sector_size = 0;
>>> --
>>> 2.28.0
>>>
>>>
>