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From: Wei Wang <wei.w.wang@intel.com>
To: Peter Xu <peterx@redhat.com>
Cc: qemu-devel@nongnu.org, dgilbert@redhat.com, quintela@redhat.com,
	mst@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2] bitmap: fix BITMAP_LAST_WORD_MASK
Date: Tue, 07 Aug 2018 16:21:15 +0800	[thread overview]
Message-ID: <5B69567B.8050309@intel.com> (raw)
In-Reply-To: <20180807073905.GA7265@xz-mi>

On 08/07/2018 03:39 PM, Peter Xu wrote:
> On Tue, Jul 31, 2018 at 06:01:18PM +0800, Wei Wang wrote:
>> When "nbits = 0", which means no bits to mask, this macro is expected to
>> return 0, instead of 0xffffffff. This patch changes the macro to return
>> 0 when there is no bit needs to be masked.
>>
>> Signed-off-by: Wei Wang <wei.w.wang@intel.com>
>> CC: Juan Quintela <quintela@redhat.com>
>> CC: Dr. David Alan Gilbert <dgilbert@redhat.com>
>> CC: Peter Xu <peterx@redhat.com>
> Reviewed-by: Peter Xu <peterx@redhat.com>
>
> Is there any existing path that can trigger this nbits==0?

Not sure about other bitmap APIs which call this macro. But it happens 
in the patches we are working on, which use bitmap_count_one.
It would be good to have the macro itself handle this corner case, so 
that callers won't need to worry about that.

Best,
Wei

  reply	other threads:[~2018-08-07  8:17 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-31 10:01 [Qemu-devel] [PATCH v2] bitmap: fix BITMAP_LAST_WORD_MASK Wei Wang
2018-07-31 14:44 ` Juan Quintela
2018-08-07  7:39 ` Peter Xu
2018-08-07  8:21   ` Wei Wang [this message]
2018-08-07  9:53     ` Dr. David Alan Gilbert
2018-08-08  1:34       ` Wei Wang
2018-08-08  8:29         ` Dr. David Alan Gilbert
2018-08-07 12:17     ` Peter Xu
2018-08-08  1:30       ` Wei Wang

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