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List:       linux-fsdevel
Subject:    Re: [replace-alexv-buffer.c-patch] Re: [PATCH] Several bad bugs in
From:       "Stephen C. Tweedie" <sct () redhat ! com>
Date:       1999-04-23 13:44:32
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Hi,

On Thu, 22 Apr 1999 15:42:15 -0400 (EDT), Alexander Viro
<viro@math.psu.edu> said:

>[snip]
>> @@ -653,10 +629,13 @@
>>  	 * around on the free list, and we can get in a loop if we are not careful.
>>  	 */
>>  	for(nlist = 0; nlist < NR_LIST; nlist++) {
>> +	refiled:
>>  		bh = lru_list[nlist];
>>  		for (i = nr_buffers_type[nlist]*2 ; --i > 0 ; bh = bhnext) {
>>  			if(!bh)
>>  				break;
>> +			if (bh->b_list != nlist)
>> +				goto refiled;

>	Ahem... Busy-waiting is fun, ain't it? What did you really mean
>in the chunk above?

It's not a busy-wait.  If bh->b_list has changed, it just means that the
"bhnext" buffer got refiled while we blocked in wait_on_buffer the
previous time round the loop.  That buffer is no longer on the current
lru_list so we won't see it after the reattempt.

--Stephen

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