From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Subject: Re: [PATCHv4 2/4] tcmu: Fix wrongly calculating of the base_command_size Date: Tue, 21 Mar 2017 15:53:09 -0400 Message-ID: <77be5d5f-c899-1379-87f6-720aa3755504@redhat.com> References: <1490085382-28658-1-git-send-email-lixiubo@cmss.chinamobile.com> <1490085382-28658-3-git-send-email-lixiubo@cmss.chinamobile.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:38752 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752625AbdCUTxR (ORCPT ); Tue, 21 Mar 2017 15:53:17 -0400 In-Reply-To: <1490085382-28658-3-git-send-email-lixiubo@cmss.chinamobile.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: lixiubo@cmss.chinamobile.com, agrover@redhat.com, nab@linux-iscsi.org Cc: shli@kernel.org, sheng@yasker.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, namei.unix@gmail.com, bryantly@linux.vnet.ibm.com On 03/21/2017 04:36 AM, lixiubo@cmss.chinamobile.com wrote: > From: Xiubo Li > > The t_data_nents and t_bidi_data_nents are the numbers of the > segments, but it couldn't be sure the block size equals to size > of the segment. > > For the worst case, all the blocks are discontiguous and there > will need the same number of iovecs, that's to say: blocks == iovs. > So here just set the number of iovs to block count needed by tcmu > cmd. > > Signed-off-by: Xiubo Li > --- > drivers/target/target_core_user.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c > index 65d475f..ae5b74f 100644 > --- a/drivers/target/target_core_user.c > +++ b/drivers/target/target_core_user.c > @@ -408,6 +408,13 @@ static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd) > return data_length; > } > > +static inline uint32_t tcmu_cmd_get_block_cnt(struct tcmu_cmd *tcmu_cmd) > +{ > + size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd); > + > + return (data_length + DATA_BLOCK_SIZE - 1) / DATA_BLOCK_SIZE; > +} Can you just do data_length / DATA_BLOCK_SIZE, because tcmu_cmd_get_data_length will return data_length as a multiple of DATA_BLOCK_SIZE.