[PATCH 1/1] Drivers: hv: vmbus: Fix ring buffer signaling

Joshua R. Poulson jrp at pun.org
Wed Mar 28 19:18:06 UTC 2018


https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v4.16-rc7&id=655296c8bbeffcf020558c4455305d597a73bde1

On Wed, Mar 28, 2018 at 12:01 PM, Stephen Hemminger
<stephen at networkplumber.org> wrote:
> On Sun,  4 Mar 2018 22:24:08 -0700
> kys at exchange.microsoft.com wrote:
>
>> From: Michael Kelley <mhkelley at outlook.com>
>>
>> Fix bugs in signaling the Hyper-V host when freeing space in the
>> host->guest ring buffer:
>>
>> 1. The interrupt_mask must not be used to determine whether to signal
>>    on the host->guest ring buffer
>> 2. The ring buffer write_index must be read (via hv_get_bytes_to_write)
>>    *after* pending_send_sz is read in order to avoid a race condition
>> 3. Comparisons with pending_send_sz must treat the "equals" case as
>>    not-enough-space
>> 4. Don't signal if the pending_send_sz feature is not present. Older
>>    versions of Hyper-V that don't implement this feature will poll.
>>
>> Fixes: 03bad714a161 ("vmbus: more host signalling avoidance")
>>
>> Cc: Stable <stable at vger.kernel.org> # 4.14 and above
>> Signed-off-by: Michael Kelley <mhkelley at outlook.com>
>> Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
>
> What ever happened to this patch? It doesn't seem to be in char-misc, upstream,
> or stable kernel tree yet.
>
>


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