nptl: Document AS-safe functions in cancellation.c.
Commit Message
On 10/4/19 4:45 PM, Zack Weinberg wrote:
> On Fri, Oct 4, 2019 at 4:01 PM Carlos O'Donell <carlos@redhat.com> wrote:
>>
>> In a recent conversation with Mathieu Desnoyer he pointed out that
>> because write is AS-safe all the wrappers around write should be
>> also AS-safe. We don't spell that out explicitly in the comments
>> for __pthread_enable_asynccancel and __pthread_disable_asynccancel
>> so I added them here.
>>
>>
>> /* The next two functions are similar to pthread_setcanceltype() but
>> more specialized for the use in the cancelable functions like write().
>> - They do not need to check parameters etc. */
>> + They do not need to check parameters etc. This function must be
>> + AS-safe, with the exception of the actual cancellation, because they
>> + are called by wrappers around AS-safe functions like write().*/
>
> Grammar nit: Either "_These functions_ must be AS-safe, ..." or
> "because _it is_ called." The former is probably better because
> consistent with the first sentence in this comment...
Yes, I actually wrote "These" first, but then cut-and-pasted it into
both functions, and rewrote "These" to "This" and forgot to clean it up.
Thanks for the review!
>> -
>> +/* This function must be AS-safe, with the exception of the actual
>> + cancellation, because they are called by wrappers around AS-safe
>> + functions like write().*/
>
> ... but then maybe you _don't_ want to add this comment as well.
v2
- Rework comments based on Zack's review.
How about v2?
8< --- 8< --- 8<
Document in comments that __pthread_enable_asynccancel and
__pthread_disable_asynccancel must be AS-safe in general with
the exception of the act of cancellation.
---
ChangeLog | 5 +++++
nptl/cancellation.c | 7 +++++--
2 files changed, 10 insertions(+), 2 deletions(-)
Comments
On Mon, Oct 7, 2019 at 1:35 AM Carlos O'Donell <carlos@redhat.com> wrote:
>
> How about v2?
Revised patch LGTM.
zw
On 10/7/19 12:58 PM, Zack Weinberg wrote:
> On Mon, Oct 7, 2019 at 1:35 AM Carlos O'Donell <carlos@redhat.com> wrote:
>>
>> How about v2?
>
> Revised patch LGTM.
Pushed. Thanks.
@@ -1,3 +1,8 @@
+2019-10-07 Carlos O'Donell <carlos@redhat.com>
+
+ * nptl/cancellation.c: Document that all functions here must be
+ AS-safe because they wrap AS-safe functions.
+
2019-10-07 Leandro Pereira <leandro.pereira@microsoft.com>
* elf/dl-load.c: Use __pread64_nocancel() instead of __lseek()+
@@ -24,7 +24,9 @@
/* The next two functions are similar to pthread_setcanceltype() but
more specialized for the use in the cancelable functions like write().
- They do not need to check parameters etc. */
+ They do not need to check parameters etc. These functions must be
+ AS-safe, with the exception of the actual cancellation, because they
+ are called by wrappers around AS-safe functions like write().*/
int
attribute_hidden
__pthread_enable_asynccancel (void)
@@ -59,7 +61,8 @@ __pthread_enable_asynccancel (void)
return oldval;
}
-
+/* See the comment for __pthread_enable_asynccancel regarding
+ the AS-safety of this function. */
void
attribute_hidden
__pthread_disable_asynccancel (int oldtype)