Jens Axboe <axboe@xxxxxxxxx> writes:
> On 1/17/24 8:59 AM, Jeff Moyer wrote:
>> Hi, Jens,
>>
>> Jens Axboe <axboe@xxxxxxxxx> writes:
>>
>>> Add compat.h include to avoid a potential build issue:
>>>
>>> io_uring/register.c:281:6: error: call to undeclared function 'in_compat_syscall'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
>>>
>>> if (in_compat_syscall()) {
>>> ^
>>> 1 warning generated.
>>> io_uring/register.c:282:9: error: call to undeclared function 'compat_get_bitmap'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
>>> ret = compat_get_bitmap(cpumask_bits(new_mask),
>>> ^
>>>
>>> Fixes: c43203154d8a ("io_uring/register: move io_uring_register(2) related code to register.c")
>>> Reported-by: Manu Bretelle <chantra@xxxxxxxx>
>>> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
>>>
>>> ---
>>>
>>> diff --git a/io_uring/register.c b/io_uring/register.c
>>> index 708dd1d89add..5e62c1208996 100644
>>> --- a/io_uring/register.c
>>> +++ b/io_uring/register.c
>>> @@ -14,6 +14,7 @@
>>> #include <linux/slab.h>
>>> #include <linux/uaccess.h>
>>> #include <linux/nospec.h>
>>> +#include <linux/compat.h>
>>> #include <linux/io_uring.h>
>>> #include <linux/io_uring_types.h>
>>
>> This makes sense to me, but I wasn't able to reproduce that build error
>> after disabling CONFIG_COMPAT.
>
> I couldn't either, but apparently it happened internally with our kdump
> config variant.
ok.
>>> @@ -278,13 +279,14 @@ static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx,
>>> if (len > cpumask_size())
>>> len = cpumask_size();
>>>
>>> - if (in_compat_syscall()) {
>>> +#ifdef CONFIG_COMPAT
>>> + if (in_compat_syscall())
>>
>> I don't think this is needed.
>>
>> linux/compat.h:
>> ...
>> #else /* !CONFIG_COMPAT */
>>
>> #define is_compat_task() (0)
>> /* Ensure no one redefines in_compat_syscall() under !CONFIG_COMPAT */
>> #define in_compat_syscall in_compat_syscall
>> static inline bool in_compat_syscall(void) { return false; }
>>
>> Isn't the code fine as-is?
>
> It probably is, but this makes it consistent with the other spots we do
> compat handling. Hence I'd prefer to keep it like that, and then perhaps
> we can prune them all at some point.
I see one other spot. :) But if you are happy with it, that's fine by
me.
> Thanks for taking a look!
Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cheers,
Jeff
