From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukas Herbolt Subject: Re: [PATCH] scsi_debug: Add OPTIMAL TRANSFER LENGTH GRANULARITY option. Date: Tue, 24 Jan 2017 12:41:17 +0100 Message-ID: References: <1483779027-10052-1-git-send-email-lherbolt@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-wm0-f51.google.com ([74.125.82.51]:33098 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750767AbdAXLlT (ORCPT ); Tue, 24 Jan 2017 06:41:19 -0500 Received: by mail-wm0-f51.google.com with SMTP id d140so42045710wmd.0 for ; Tue, 24 Jan 2017 03:41:19 -0800 (PST) In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Martin K. Petersen" Cc: dgilbert@interlog.com, linux-scsi@vger.kernel.org Sounds ok to me. --- drivers/scsi/scsi_debug.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index cf04a36..a4456ca 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -125,6 +125,7 @@ static const char *sdebug_version_date = "20160430"; #define DEF_OPTS 0 #define DEF_OPT_BLKS 1024 #define DEF_PHYSBLK_EXP 0 +#define DEF_OPT_XFERLEN_EXP 0 #define DEF_PTYPE TYPE_DISK #define DEF_REMOVABLE false #define DEF_SCSI_LEVEL 7 /* INQUIRY, byte2 [6->SPC-4; 7->SPC-5] */ @@ -590,6 +591,7 @@ static int sdebug_num_tgts = DEF_NUM_TGTS; /* targets per host */ static int sdebug_opt_blks = DEF_OPT_BLKS; static int sdebug_opts = DEF_OPTS; static int sdebug_physblk_exp = DEF_PHYSBLK_EXP; +static int sdebug_opt_xferlen_exp = DEF_OPT_XFERLEN_EXP; static int sdebug_ptype = DEF_PTYPE; /* SCSI peripheral device type */ static int sdebug_scsi_level = DEF_SCSI_LEVEL; static int sdebug_sector_size = DEF_SECTOR_SIZE; @@ -1205,7 +1207,10 @@ static int inquiry_vpd_b0(unsigned char *arr) memcpy(arr, vpdb0_data, sizeof(vpdb0_data)); /* Optimal transfer length granularity */ - gran = 1 << sdebug_physblk_exp; + if (sdebug_opt_xferlen_exp != 0 && sdebug_physblk_exp < sdebug_opt_xferlen_exp) + gran = 1 << sdebug_opt_xferlen_exp; + else + gran = 1 << sdebug_physblk_exp; put_unaligned_be16(gran, arr + 2); /* Maximum Transfer Length */ @@ -4161,6 +4166,7 @@ module_param_named(num_tgts, sdebug_num_tgts, int, S_IRUGO | S_IWUSR); module_param_named(opt_blks, sdebug_opt_blks, int, S_IRUGO); module_param_named(opts, sdebug_opts, int, S_IRUGO | S_IWUSR); module_param_named(physblk_exp, sdebug_physblk_exp, int, S_IRUGO); +module_param_named(opt_xferlen_exp, sdebug_opt_xferlen_exp, int, S_IRUGO); module_param_named(ptype, sdebug_ptype, int, S_IRUGO | S_IWUSR); module_param_named(removable, sdebug_removable, bool, S_IRUGO | S_IWUSR); module_param_named(scsi_level, sdebug_scsi_level, int, S_IRUGO); @@ -4212,6 +4218,7 @@ MODULE_PARM_DESC(num_tgts, "number of targets per host to simulate(def=1)"); MODULE_PARM_DESC(opt_blks, "optimal transfer length in blocks (def=1024)"); MODULE_PARM_DESC(opts, "1->noise, 2->medium_err, 4->timeout, 8->recovered_err... (def=0)"); MODULE_PARM_DESC(physblk_exp, "physical block exponent (def=0)"); +MODULE_PARM_DESC(opt_xferlen_exp, "optimal transfer length granularity exponent (def=physblk_exp)"); MODULE_PARM_DESC(ptype, "SCSI peripheral type(def=0[disk])"); MODULE_PARM_DESC(removable, "claim to have removable media (def=0)"); MODULE_PARM_DESC(scsi_level, "SCSI level to simulate(def=7[SPC-5])"); -- 2.7.4 On Sat, Jan 21, 2017 at 1:24 AM, Martin K. Petersen wrote: >>>>>> "Lukas" == Lukas Herbolt writes: > > Lukas, > > Lukas> I have been playing with scsi_debug and found that there is no > Lukas> way how to change the minimum_io_size (OPTIMAL TRANSFER LENGTH > Lukas> GRANULARITY reported by VPD 0xb0). > > Lukas> The current module has minimum_io_size always set to > Lukas> physical_block_size. So here comes a small patch which add a new > Lukas> option to this module to be able to set it independently to the > Lukas> physical_block_size. Default behavior is to keep the > Lukas> minimum_io_size equal to the physical_block_size. > > No objection to the functionality but I don't really like the naming > scheme. There are many granularities in SBC so "gran" isn't particularly > descriptive. > > How about opt_xferlen_exp or something like that? > > -- > Martin K. Petersen Oracle Linux Engineering