From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Dexuan Cui <decui@microsoft.com>
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
driverdev-devel@linuxdriverproject.org, olaf@aepfle.de,
apw@canonical.com, jasowang@redhat.com, kys@microsoft.com,
haiyangz@microsoft.com
Subject: Re: [PATCH] hv: hv_fcopy: drop the obsolete message on transfer failure
Date: Wed, 12 Nov 2014 10:41:03 +0100 [thread overview]
Message-ID: <87oasc69jk.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <1415768606-28538-1-git-send-email-decui@microsoft.com> (Dexuan Cui's message of "Tue, 11 Nov 2014 21:03:26 -0800")
Dexuan Cui <decui@microsoft.com> writes:
> In the case the user-space daemon crashes, hangs or is killed, we
> need to down the semaphore, otherwise, after the daemon starts next
> time, the obsolete data in fcopy_transaction.message or
> fcopy_transaction.fcopy_msg will be used immediately.
>
> Cc: K. Y. Srinivasan <kys@microsoft.com>
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> drivers/hv/hv_fcopy.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c
> index 23b2ce2..177122a 100644
> --- a/drivers/hv/hv_fcopy.c
> +++ b/drivers/hv/hv_fcopy.c
> @@ -86,6 +86,15 @@ static void fcopy_work_func(struct work_struct *dummy)
> * process the pending transaction.
> */
> fcopy_respond_to_host(HV_E_FAIL);
> +
> + /* In the case the user-space daemon crashes, hangs or is killed, we
> + * need to down the semaphore, otherwise, after the daemon starts next
> + * time, the obsolete data in fcopy_transaction.message or
> + * fcopy_transaction.fcopy_msg will be used immediately.
> + */
> + if (down_trylock(&fcopy_transaction.read_sema))
> + pr_debug("FCP: failed to acquire the semaphore\n");
> +
> }
>
> static int fcopy_handle_handshake(u32 version)
--
Vitaly
next prev parent reply other threads:[~2014-11-12 9:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-12 5:03 [PATCH] hv: hv_fcopy: drop the obsolete message on transfer failure Dexuan Cui
2014-11-12 9:41 ` Vitaly Kuznetsov [this message]
2014-11-19 22:59 ` KY Srinivasan
2014-11-20 7:47 ` Dexuan Cui
2014-11-20 17:58 ` KY Srinivasan
2014-11-21 2:41 ` Dexuan Cui
2014-11-21 18:29 ` KY Srinivasan
2014-11-26 23:54 ` Greg KH
2014-11-27 6:21 ` Dexuan Cui
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