Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033018AbbKEIvo (ORCPT ); Thu, 5 Nov 2015 03:51:44 -0500 Received: from mx2.suse.de ([195.135.220.15]:35681 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030329AbbKEIvj (ORCPT ); Thu, 5 Nov 2015 03:51:39 -0500 Message-ID: <563B1899.6050308@suse.de> Date: Thu, 05 Nov 2015 09:51:37 +0100 From: Hannes Reinecke User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Brian King , Laurent Vivier , martin.petersen@oracle.com CC: tyreld@linux.vnet.ibm.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 3/3] ibmvscsi: Allow to configure maximum LUN References: <1446632451-22365-1-git-send-email-lvivier@redhat.com> <1446632451-22365-4-git-send-email-lvivier@redhat.com> <5639E904.1070100@suse.de> <5639F020.4010308@redhat.com> <563A01CC.20809@suse.de> <563A8F83.7010601@linux.vnet.ibm.com> In-Reply-To: <563A8F83.7010601@linux.vnet.ibm.com> Content-Type: multipart/mixed; boundary="------------010502040501080905080906" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9049 Lines: 253 This is a multi-part message in MIME format. --------------010502040501080905080906 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit On 11/05/2015 12:06 AM, Brian King wrote: > On 11/04/2015 07:02 AM, Hannes Reinecke wrote: >> On 11/04/2015 12:46 PM, Laurent Vivier wrote: >>> >>> >>> On 04/11/2015 12:16, Hannes Reinecke wrote: >>>> On 11/04/2015 11:20 AM, Laurent Vivier wrote: >>>>> QEMU allows until 32 LUNs. >>>>> >>>>> Signed-off-by: Laurent Vivier >>>>> --- >>>>> drivers/scsi/ibmvscsi/ibmvscsi.c | 5 ++++- >>>>> 1 file changed, 4 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c >>>>> index 04de287..4480d3e 100644 >>>>> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c >>>>> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c >>>>> @@ -84,6 +84,7 @@ >>>>> */ >>>>> static int max_id = 64; >>>>> static int max_channel = 3; >>>>> +static int max_lun = 8; >>>>> static int init_timeout = 300; >>>>> static int login_timeout = 60; >>>>> static int info_timeout = 30; >>>>> @@ -117,6 +118,8 @@ module_param_named(fast_fail, fast_fail, int, S_IRUGO | S_IWUSR); >>>>> MODULE_PARM_DESC(fast_fail, "Enable fast fail. [Default=1]"); >>>>> module_param_named(client_reserve, client_reserve, int, S_IRUGO ); >>>>> MODULE_PARM_DESC(client_reserve, "Attempt client managed reserve/release"); >>>>> +module_param(max_lun, int, S_IRUGO); >>>>> +MODULE_PARM_DESC(max_lun, "Maximum LUN value [Default=8]"); >>>>> >>>>> static void ibmvscsi_handle_crq(struct viosrp_crq *crq, >>>>> struct ibmvscsi_host_data *hostdata); >>>>> @@ -2289,7 +2292,7 @@ static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id) >>>>> goto init_pool_failed; >>>>> } >>>>> >>>>> - host->max_lun = 8; >>>>> + host->max_lun = max_lun; >>>>> host->max_id = max_id; >>>>> host->max_channel = max_channel; >>>>> host->max_cmd_len = 16; >>>>> >>>> Please, don't do this. >>>> >>>> 'max_lun' should only be set if the HBA / transport has some hard >>>> limitations on the number of bytes it can use. >>>> Otherwise the scanning algorithm in scsi_scan.c should do the >>>> correct thing, independent on the 'max_lun' setting. >>> >>> So you are saying we can remove the line ? >>> >> Ho-hum. In principle you could, as ibmvscsi is using SRP internally, >> which does support 64 bit LUNs. >> >> However, due to some weird design decisions there is >> the function 'lun_from_dev()', which mangles the incoming LUN number >> into something ... else. >> Which leaves only 4 bits free for the actual LUN number, requiring >> you to use max_lun = 16. >> >> Personally I would just do away with that function and use the >> incoming LUN numbers as is. > > I pulled out my copy of SAM, what lun_from_dev is doing is translating > the incoming bus / id / LUN to a LUN in the logical unit addressing format, > as defined in 4.6.9 of SAM-4. > > -------------------------------------- > |Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | > -------------------------------------- > | n | (10b) | Target | > -------------------------------------- > | n+1| Bus | LUN | > -------------------------------------- > > So this means, in the current implementation, we have 6 bits for target (max=63), > 3 bits for bus (max=7), and 5 bits for LUN (max=31). > > It might not be a bad idea to enforce these limits on the module parameters. Otherwise > we'll have a mess when we run through lun_from_dev... > Correct. With the current implementation we need to set max_lun to 31. > As far as eliminating lun_from_dev and just passing the LUN through, I don't think we > can do that. The LUN list returned by Report LUNs to a VSCSI disk assumes we are > doing the translation above. > ? How can that be ? REPORT LUNs will give you a list of available LUNs _from that target_. As the SCSI stack now moved to handle full 64bit LUNs the values from REPORT LUNs will be used as-is (well, byte-swapped, but still). Can you test with the attached patch? Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N?rnberg GF: F. Imend?rffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG N?rnberg) --------------010502040501080905080906 Content-Type: text/x-patch; name="0001-ibmvscsi-Allow-64bit-LUNs.patch" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="0001-ibmvscsi-Allow-64bit-LUNs.patch" =46rom 42d920e9ff2a4739d4a901e033a93364586c840c Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Thu, 5 Nov 2015 09:50:23 +0100 Subject: [PATCH] ibmvscsi: Allow 64bit LUNs The SRP protocol allows full 64bit LUNs, so there is no need to mangle the LUNs in the driver. Signed-off-by: Hannes Reinecke --- drivers/scsi/ibmvscsi/ibmvscsi.c | 25 ++++++------------------- 1 file changed, 6 insertions(+), 19 deletions(-) diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibm= vscsi.c index 6a41c36..0162b1d 100644 --- a/drivers/scsi/ibmvscsi/ibmvscsi.c +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c @@ -1019,16 +1019,6 @@ static void handle_cmd_rsp(struct srp_event_struct= *evt_struct) } =20 /** - * lun_from_dev: - Returns the lun of the scsi device - * @dev: struct scsi_device - * -*/ -static inline u16 lun_from_dev(struct scsi_device *dev) -{ - return (0x2 << 14) | (dev->id << 8) | (dev->channel << 5) | dev->lun; -} - -/** * ibmvscsi_queue: - The queuecommand function of the scsi template=20 * @cmd: struct scsi_cmnd to be executed * @done: Callback function to be called when cmd is completed @@ -1040,7 +1030,6 @@ static int ibmvscsi_queuecommand_lck(struct scsi_cm= nd *cmnd, struct srp_event_struct *evt_struct; struct srp_indirect_buf *indirect; struct ibmvscsi_host_data *hostdata =3D shost_priv(cmnd->device->host);= - u16 lun =3D lun_from_dev(cmnd->device); u8 out_fmt, in_fmt; =20 cmnd->result =3D (DID_OK << 16); @@ -1053,7 +1042,7 @@ static int ibmvscsi_queuecommand_lck(struct scsi_cm= nd *cmnd, memset(srp_cmd, 0x00, SRP_MAX_IU_LEN); srp_cmd->opcode =3D SRP_CMD; memcpy(srp_cmd->cdb, cmnd->cmnd, sizeof(srp_cmd->cdb)); - int_to_scsilun(lun, &srp_cmd->lun); + int_to_scsilun(cmnd->device->lun, &srp_cmd->lun); =20 if (!map_data_for_srp_cmd(cmnd, evt_struct, srp_cmd, hostdata->dev)) { if (!firmware_has_feature(FW_FEATURE_CMO)) @@ -1489,7 +1478,6 @@ static int ibmvscsi_eh_abort_handler(struct scsi_cm= nd *cmd) union viosrp_iu srp_rsp; int rsp_rc; unsigned long flags; - u16 lun =3D lun_from_dev(cmd->device); unsigned long wait_switch =3D 0; =20 /* First, find this command in our sent list so we can figure @@ -1529,7 +1517,7 @@ static int ibmvscsi_eh_abort_handler(struct scsi_cm= nd *cmd) /* Set up an abort SRP command */ memset(tsk_mgmt, 0x00, sizeof(*tsk_mgmt)); tsk_mgmt->opcode =3D SRP_TSK_MGMT; - int_to_scsilun(lun, &tsk_mgmt->lun); + int_to_scsilun(cmnd->device->lun, &tsk_mgmt->lun); tsk_mgmt->tsk_mgmt_func =3D SRP_TSK_ABORT_TASK; tsk_mgmt->task_tag =3D (u64) found_evt; =20 @@ -1556,7 +1544,7 @@ static int ibmvscsi_eh_abort_handler(struct scsi_cm= nd *cmd) =20 sdev_printk(KERN_INFO, cmd->device, "aborting command. lun 0x%llx, tag 0x%llx\n", - (((u64) lun) << 48), (u64) found_evt); + cmd->device->lun, (u64) found_evt); =20 wait_for_completion(&evt->comp); =20 @@ -1628,7 +1616,6 @@ static int ibmvscsi_eh_device_reset_handler(struct = scsi_cmnd *cmd) union viosrp_iu srp_rsp; int rsp_rc; unsigned long flags; - u16 lun =3D lun_from_dev(cmd->device); unsigned long wait_switch =3D 0; =20 spin_lock_irqsave(hostdata->host->host_lock, flags); @@ -1652,7 +1639,7 @@ static int ibmvscsi_eh_device_reset_handler(struct = scsi_cmnd *cmd) /* Set up a lun reset SRP command */ memset(tsk_mgmt, 0x00, sizeof(*tsk_mgmt)); tsk_mgmt->opcode =3D SRP_TSK_MGMT; - int_to_scsilun(lun, &tsk_mgmt->lun); + int_to_scsilun(cmnd->device->lun, &tsk_mgmt->lun); tsk_mgmt->tsk_mgmt_func =3D SRP_TSK_LUN_RESET; =20 evt->sync_srp =3D &srp_rsp; @@ -1677,7 +1664,7 @@ static int ibmvscsi_eh_device_reset_handler(struct = scsi_cmnd *cmd) } =20 sdev_printk(KERN_INFO, cmd->device, "resetting device. lun 0x%llx\n", - (((u64) lun) << 48)); + cmnd->device->lun); =20 wait_for_completion(&evt->comp); =20 @@ -2289,7 +2276,7 @@ static int ibmvscsi_probe(struct vio_dev *vdev, con= st struct vio_device_id *id) goto init_pool_failed; } =20 - host->max_lun =3D 8; + host->max_lun =3D 0xFFFF; host->max_id =3D max_id; host->max_channel =3D max_channel; host->max_cmd_len =3D 16; --=20 1.8.5.6 --------------010502040501080905080906-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/