From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:43736 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729001AbfFXPNg (ORCPT ); Mon, 24 Jun 2019 11:13:36 -0400 Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5OExIpR007352 for ; Mon, 24 Jun 2019 11:13:35 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0b-001b2d01.pphosted.com with ESMTP id 2tb017kucb-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 24 Jun 2019 11:13:34 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 24 Jun 2019 16:13:32 +0100 Subject: Re: [PATCH V5 10/16] s390: zfcp_fc: use sg helper to operate scatterlist References: <20190618013757.22401-1-ming.lei@redhat.com> <20190618013757.22401-11-ming.lei@redhat.com> From: Steffen Maier Date: Mon, 24 Jun 2019 17:13:24 +0200 MIME-Version: 1.0 In-Reply-To: <20190618013757.22401-11-ming.lei@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Message-Id: <95bfa1fb-d0eb-fc61-ecc0-001ae52a326f@linux.ibm.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: Ming Lei , linux-scsi@vger.kernel.org, "Martin K . Petersen" Cc: James Bottomley , Bart Van Assche , Hannes Reinecke , Christoph Hellwig , Jim Gill , Cathy Avery , "Ewan D . Milne" , Brian King , James Smart , "Juergen E . Fischer" , Michael Schmitz , Finn Thain , Greg Kroah-Hartman , devel@driverdev.osuosl.org, linux-usb@vger.kernel.org, Dan Carpenter , Benjamin Block , Martin Schwidefsky , Heiko Carstens , linux-s390@vger.kernel.org Hi Ming, On 6/18/19 3:37 AM, Ming Lei wrote: > Use the scatterlist iterators and remove direct indexing of the > scatterlist array. > > This way allows us to pre-allocate one small scatterlist, which can be > chained with one runtime allocated scatterlist if the pre-allocated one > isn't enough for the whole request. > > Cc: Steffen Maier > Cc: Benjamin Block > Cc: Martin Schwidefsky > Cc: Heiko Carstens > Cc: linux-s390@vger.kernel.org > Acked-by: Benjamin Block > Reviewed-by: Christoph Hellwig > Reviewed-by: Bart Van Assche > Signed-off-by: Ming Lei > --- > drivers/s390/scsi/zfcp_fc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/s390/scsi/zfcp_fc.c b/drivers/s390/scsi/zfcp_fc.c > index 33eddb02ee30..b018b61bd168 100644 > --- a/drivers/s390/scsi/zfcp_fc.c > +++ b/drivers/s390/scsi/zfcp_fc.c > @@ -620,7 +620,7 @@ static void zfcp_fc_sg_free_table(struct scatterlist *sg, int count) > { > int i; > > - for (i = 0; i < count; i++, sg++) > + for (i = 0; i < count; i++, sg = sg_next(sg)) > if (sg) > free_page((unsigned long) sg_virt(sg)); > else > @@ -641,7 +641,7 @@ static int zfcp_fc_sg_setup_table(struct scatterlist *sg, int count) > int i; > > sg_init_table(sg, count); > - for (i = 0; i < count; i++, sg++) { > + for (i = 0; i < count; i++, sg = sg_next(sg)) { > addr = (void *) get_zeroed_page(GFP_KERNEL); > if (!addr) { > zfcp_fc_sg_free_table(sg, i); > I'm still catching up with emails that came during my vacation, so I'm not fully up-to-date on the current state of this and how to bring in potential fixups on top. I think, we also have two more (not so obvious) places in the corresponding response/completion code path, where we might need to introduce the proper iterator helper: zfcp_fsf.c: static int zfcp_fc_eval_gpn_ft(struct zfcp_fc_req *fc_req, struct zfcp_adapter *adapter, int max_entries) { struct scatterlist *sg = &fc_req->sg_rsp; ... /* first entry is the header */ for (x = 1; x < max_entries && !last; x++) { ... if (x % (ZFCP_FC_GPN_FT_ENT_PAGE + 1)) ... else acc = sg_virt(++sg); ^^^^ zfcp_dbf.c: static u16 zfcp_dbf_san_res_cap_len_if_gpn_ft(char *tag, struct zfcp_fsf_req *fsf, u16 len) { struct scatterlist *resp_entry = ct_els->resp; ... /* the basic CT_IU preamble is the same size as one entry in the GPN_FT * response, allowing us to skip special handling for it - just skip it */ for (x = 1; x < max_entries && !last; x++) { if (x % (ZFCP_FC_GPN_FT_ENT_PAGE + 1)) ... else acc = sg_virt(++resp_entry); ^^^^^^^^^^^^ What do you think? -- Mit freundlichen Gruessen / Kind regards Steffen Maier Linux on IBM Z Development https://www.ibm.com/privacy/us/en/ IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Matthias Hartmann Geschaeftsfuehrung: Dirk Wittkopp Sitz der Gesellschaft: Boeblingen Registergericht: Amtsgericht Stuttgart, HRB 243294 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Maier Subject: Re: [PATCH V5 10/16] s390: zfcp_fc: use sg helper to operate scatterlist Date: Mon, 24 Jun 2019 17:13:24 +0200 Message-ID: <95bfa1fb-d0eb-fc61-ecc0-001ae52a326f@linux.ibm.com> References: <20190618013757.22401-1-ming.lei@redhat.com> <20190618013757.22401-11-ming.lei@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190618013757.22401-11-ming.lei@redhat.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" To: Ming Lei , linux-scsi@vger.kernel.org, "Martin K . Petersen" Cc: Michael Schmitz , devel@driverdev.osuosl.org, Hannes Reinecke , Benjamin Block , Bart Van Assche , linux-s390@vger.kernel.org, Greg Kroah-Hartman , linux-usb@vger.kernel.org, Heiko Carstens , James Smart , "Ewan D . Milne" , Jim Gill , James Bottomley , Brian King , Finn Thain , Martin Schwidefsky , "Juergen E . Fischer" , Christoph Hellwig , Dan Carpenter List-Id: linux-scsi@vger.kernel.org Hi Ming, On 6/18/19 3:37 AM, Ming Lei wrote: > Use the scatterlist iterators and remove direct indexing of the > scatterlist array. > > This way allows us to pre-allocate one small scatterlist, which can be > chained with one runtime allocated scatterlist if the pre-allocated one > isn't enough for the whole request. > > Cc: Steffen Maier > Cc: Benjamin Block > Cc: Martin Schwidefsky > Cc: Heiko Carstens > Cc: linux-s390@vger.kernel.org > Acked-by: Benjamin Block > Reviewed-by: Christoph Hellwig > Reviewed-by: Bart Van Assche > Signed-off-by: Ming Lei > --- > drivers/s390/scsi/zfcp_fc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/s390/scsi/zfcp_fc.c b/drivers/s390/scsi/zfcp_fc.c > index 33eddb02ee30..b018b61bd168 100644 > --- a/drivers/s390/scsi/zfcp_fc.c > +++ b/drivers/s390/scsi/zfcp_fc.c > @@ -620,7 +620,7 @@ static void zfcp_fc_sg_free_table(struct scatterlist *sg, int count) > { > int i; > > - for (i = 0; i < count; i++, sg++) > + for (i = 0; i < count; i++, sg = sg_next(sg)) > if (sg) > free_page((unsigned long) sg_virt(sg)); > else > @@ -641,7 +641,7 @@ static int zfcp_fc_sg_setup_table(struct scatterlist *sg, int count) > int i; > > sg_init_table(sg, count); > - for (i = 0; i < count; i++, sg++) { > + for (i = 0; i < count; i++, sg = sg_next(sg)) { > addr = (void *) get_zeroed_page(GFP_KERNEL); > if (!addr) { > zfcp_fc_sg_free_table(sg, i); > I'm still catching up with emails that came during my vacation, so I'm not fully up-to-date on the current state of this and how to bring in potential fixups on top. I think, we also have two more (not so obvious) places in the corresponding response/completion code path, where we might need to introduce the proper iterator helper: zfcp_fsf.c: static int zfcp_fc_eval_gpn_ft(struct zfcp_fc_req *fc_req, struct zfcp_adapter *adapter, int max_entries) { struct scatterlist *sg = &fc_req->sg_rsp; ... /* first entry is the header */ for (x = 1; x < max_entries && !last; x++) { ... if (x % (ZFCP_FC_GPN_FT_ENT_PAGE + 1)) ... else acc = sg_virt(++sg); ^^^^ zfcp_dbf.c: static u16 zfcp_dbf_san_res_cap_len_if_gpn_ft(char *tag, struct zfcp_fsf_req *fsf, u16 len) { struct scatterlist *resp_entry = ct_els->resp; ... /* the basic CT_IU preamble is the same size as one entry in the GPN_FT * response, allowing us to skip special handling for it - just skip it */ for (x = 1; x < max_entries && !last; x++) { if (x % (ZFCP_FC_GPN_FT_ENT_PAGE + 1)) ... else acc = sg_virt(++resp_entry); ^^^^^^^^^^^^ What do you think? -- Mit freundlichen Gruessen / Kind regards Steffen Maier Linux on IBM Z Development https://www.ibm.com/privacy/us/en/ IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Matthias Hartmann Geschaeftsfuehrung: Dirk Wittkopp Sitz der Gesellschaft: Boeblingen Registergericht: Amtsgericht Stuttgart, HRB 243294