Re: [PATCH] kiobuf/rawio fixes for 2.4.0-test10-pre6

[Christoph Hellwig <hch@ns.caldera.de>]

Andrea Arcangeli <andrea@suse.de> wrote:
>> +		map = follow_page(ptr, datain, &failed);
>> +		if (failed) {
>> +			/*
>> +			 * Page got stolen before we could lock it down.
>> +			 * Retry.
>> +			 */
>>  			spin_unlock(&mm->page_table_lock);
>> -			dprintk (KERN_ERR "Missing page in map_user_kiobuf\n");
>> -			goto out_unlock;
>> +			goto faultin;

> This is suboptimal (walks the pagetables twice if the page is just mapped). It
> should be a follow page first and handle_mm_fault only if follow page failed.

I did only forward-port the fixes from Stpehen's 2.3.99pre2 patchset
because no one else seemed to be interested. If someone with more
vm-experience (e.g. you) gets interested because of this patch: fine.

	Christoph


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