Re: [PATCH] Make xmalloc and xrealloc thread-safe

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 24, 2010, 21:28 UTC
Message-ID: <7vsk7p4df0.fsf@alter.siamese.dyndns.org>
In-Reply-To: <20100324202814.GA24830@spearce.org>

"Shawn O. Pearce" <spearce@spearce.org> writes:

Show 11 quoted lines

>> @@ -100,7 +112,7 @@ void *xmmap(void *start, size_t length,
>>  	if (ret == MAP_FAILED) {
>>  		if (!length)
>>  			return NULL;
>> -		release_pack_memory(length, fd);
>> +		try_to_free_routine(length);
>
> This isn't dubious!  The fd passed here is to prevent the pack release
> code from closing this fd right before we try to mmap it.  Its an actual
> bug fix that I had to write years ago, check the history of that section
> of code...  :-)

A tangent.

I thought that it incidentally might be a good example for the "line-mode" log that has been discussed recently to follow the history of this code, but this turns out to be too easy:

$ git blame -C -L'/^void \*xmmap/,/^}/' wrapper.c

directly gives you the answer. d1efefa4 explains why this passes fd rather well.