From: Max Reitz <mreitz@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org
Cc: kwolf@redhat.com, qemu-block@nongnu.org
Subject: Re: [PATCH v3 3/7] block: add max_hw_transfer to BlockLimits
Date: Wed, 16 Jun 2021 15:46:40 +0200 [thread overview]
Message-ID: <664fb7dd-a6ca-9165-8ed7-24dac1c0ef81@redhat.com> (raw)
In-Reply-To: <a684c31d-9da3-9e75-89c0-c68997760108@redhat.com>
On 16.06.21 15:18, Paolo Bonzini wrote:
> On 15/06/21 18:18, Max Reitz wrote:
>>> }
>>> +/* Returns the maximum hardware transfer length, in bytes;
>>> guaranteed nonzero */
>>> +uint64_t blk_get_max_hw_transfer(BlockBackend *blk)
>>> +{
>>> + BlockDriverState *bs = blk_bs(blk);
>>> + uint64_t max = INT_MAX;
>>> +
>>> + if (bs) {
>>> + max = MIN_NON_ZERO(bs->bl.max_hw_transfer,
>>> bs->bl.max_transfer);
>>> + }
>>> + return max;
>>
>> Both `max_hw_transfer` and `max_transfer` can be 0, so this could
>> return 0, contrary to what the comment above promises.
>>
>> Should `max` be initialized to 0 with a `MIN_NON_ZERO(max, INT_MAX)`
>> here (like `blk_get_max_transfer()` does it)?
>
> Yes, something to that effect.
>
>> (As for the rest, I think aligning to the request alignment makes
>> sense, but then again we don’t do that for max_transfer either, so...
>> this at least wouldn’t be a new bug.
>
> Ok, will do. I will also add a new patch to align max_transfer to the
> request alignment.
>
>> Regarding the comment, checkpatch complains about it, so it should be
>> fixed so that /* is on its own line.
>
> That makes it different from every other comment in block_int.h
> though. Is it okay to fix all of them in a follow-up?
The reason it’s different is that the comment style in question was
added to checkpatch only relatively recently. I can’t speak for others,
but I’m a simple person. I just do what makes checkpatch happy. :)
Given that the checkpatch complaint is only a warning, I think it’s OK
to keep the comment as it is here, and perhaps optionally fix all
comments in block_int.h in a follow-up. I don’t think we need to fix
existing comments, but, well, it wouldn’t be wrong.
Max
next prev parent reply other threads:[~2021-06-16 13:48 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-03 13:37 [PATCH v3 0/7] block: file-posix queue Paolo Bonzini
2021-06-03 13:37 ` [PATCH v3 1/7] file-posix: fix max_iov for /dev/sg devices Paolo Bonzini
2021-06-07 5:39 ` Vladimir Sementsov-Ogievskiy
2021-06-07 6:16 ` Vladimir Sementsov-Ogievskiy
2021-06-07 7:23 ` Vladimir Sementsov-Ogievskiy
2021-06-15 15:58 ` Max Reitz
2021-06-03 13:37 ` [PATCH v3 2/7] scsi-generic: pass max_segments via max_iov field in BlockLimits Paolo Bonzini
2021-06-15 16:06 ` Max Reitz
2021-06-15 16:20 ` Max Reitz
2021-06-15 17:41 ` Paolo Bonzini
2021-06-03 13:37 ` [PATCH v3 3/7] block: add max_hw_transfer to BlockLimits Paolo Bonzini
2021-06-03 17:33 ` Eric Blake
2021-06-04 7:21 ` Paolo Bonzini
2021-06-15 16:18 ` Max Reitz
2021-06-16 13:18 ` Paolo Bonzini
2021-06-16 13:46 ` Max Reitz [this message]
2021-06-17 9:59 ` Paolo Bonzini
2021-06-03 13:37 ` [PATCH v3 4/7] file-posix: try BLKSECTGET on block devices too, do not round to power of 2 Paolo Bonzini
2021-06-15 16:32 ` Max Reitz
2021-06-03 13:37 ` [PATCH v3 5/7] block: feature detection for host block support Paolo Bonzini
2021-06-15 16:40 ` Max Reitz
2021-06-03 13:37 ` [PATCH v3 6/7] block: check for sys/disk.h Paolo Bonzini
2021-06-15 16:42 ` Max Reitz
2021-06-03 13:37 ` [PATCH v3 7/7] block: detect DKIOCGETBLOCKCOUNT/SIZE before use Paolo Bonzini
2021-06-15 16:50 ` Max Reitz
2021-06-15 16:57 ` Daniel P. Berrangé
2021-06-07 13:52 ` [PATCH v3 0/7] block: file-posix queue Maxim Levitsky
2021-06-10 13:40 ` Paolo Bonzini
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