From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from NAM01-BY2-obe.outbound.protection.outlook.com (mail-by2nam01on071b.outbound.protection.outlook.com [IPv6:2a01:111:f400:fe42::71b]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 2D61A80350 for ; Tue, 7 Mar 2017 11:05:47 -0800 (PST) Subject: Re: [PATCH 2/3] Allow specifying a default DSM family References: <1773e8607ae49fefbb288509603a0db353a72d91.1488844291.git.linda.knippers@hpe.com> <58BE0E06.7020309@hpe.com> <58BF0336.4090606@hpe.com> From: Linda Knippers Message-ID: <58BF0485.1090003@hpe.com> Date: Tue, 7 Mar 2017 14:05:41 -0500 MIME-Version: 1.0 In-Reply-To: <58BF0336.4090606@hpe.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: "linux-nvdimm@lists.01.org" List-ID: On 03/07/2017 02:00 PM, Linda Knippers wrote: > On 03/06/2017 08:56 PM, Dan Williams wrote: >> On Mon, Mar 6, 2017 at 5:33 PM, Linda Knippers wrote: >>> On 03/06/2017 07:39 PM, Dan Williams wrote: >>>> On Mon, Mar 6, 2017 at 4:25 PM, Linda Knippers wrote: >>>>> Provide the ability to request a default DSM family. If it is not >>>>> supported, then fall back to the normal discovery order. >>>>> >>>>> This is helpful for testing platforms that support multiple DSM families. >>>>> It will also allow administrators to request the DSM family that their >>>>> management tools support, which may not be the first one found using >>>>> the current discovery order. >>>>> >>>>> Signed-off-by: Linda Knippers >>>>> --- >>>>> drivers/acpi/nfit/core.c | 26 ++++++++++++++++++++++---- >>>>> 1 file changed, 22 insertions(+), 4 deletions(-) >>>>> >>>>> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c >>>>> index 97d42ff..78c46a7 100644 >>>>> --- a/drivers/acpi/nfit/core.c >>>>> +++ b/drivers/acpi/nfit/core.c >>>>> @@ -55,6 +55,11 @@ >>>>> module_param(override_dsm_mask, ulong, S_IRUGO); >>>>> MODULE_PARM_DESC(override_dsm_mask, "Bitmask of allowed NVDIMM DSM functions"); >>>>> >>>>> +static int default_dsm_family = -1; >>>>> +module_param(default_dsm_family, int, S_IRUGO); >>>>> +MODULE_PARM_DESC(default_dsm_family, >>>>> + "Try this DSM type first when identifying NVDIMM family"); >>>>> + >>>>> LIST_HEAD(acpi_descs); >>>>> DEFINE_MUTEX(acpi_desc_lock); >>>>> >>>>> @@ -1371,7 +1376,7 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc, >>>>> struct device *dev = acpi_desc->dev; >>>>> unsigned long dsm_mask; >>>>> const u8 *uuid; >>>>> - int i; >>>>> + int i = -1; >>>>> >>>>> /* nfit test assumes 1:1 relationship between commands and dsms */ >>>>> nfit_mem->dsm_mask = acpi_desc->dimm_cmd_force_en; >>>>> @@ -1399,10 +1404,23 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc, >>>>> * Until standardization materializes we need to consider 4 >>>>> * different command sets. Note, that checking for function0 (bit0) >>>>> * tells us if any commands are reachable through this uuid. >>>>> + * First check for a requested default. >>>>> */ >>>>> - for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_MSFT; i++) >>>>> - if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1)) >>>>> - break; >>>>> + if (default_dsm_family >= NVDIMM_FAMILY_INTEL && >>>>> + default_dsm_family <= NVDIMM_FAMILY_MSFT) { >>>>> + if (acpi_check_dsm(adev_dimm->handle, >>>>> + to_nfit_uuid(default_dsm_family), 1, 1)) >>>>> + i = default_dsm_family; >>>>> + else >>>>> + dev_dbg(dev, "default_dsm_family %d not supported\n", >>>>> + default_dsm_family); >>>>> + } >>>>> + if (i == -1) { >>>>> + for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_MSFT; i++) >>>>> + if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), >>>>> + 1, 1)) >>>>> + break; >>>>> + } >>>> >>>> I think we can make this simpler and more deterministic with a "force" >>>> option? Something like: >>>> >>>> @@ -1397,8 +1397,12 @@ static int acpi_nfit_add_dimm(struct >>>> acpi_nfit_desc *acpi_desc, >>>> * tells us if any commands are reachable through this uuid. >>>> */ >>>> for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_MSFT; i++) >>>> - if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1)) >>>> - break; >>>> + if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1)) { >>>> + if (force_dsm_family < 0) >>>> + break; >>>> + else if (i == force_dsm_family) >>>> + break; >>>> + } >>>> >>>> /* limit the supported commands to those that are publicly documented */ >>>> nfit_mem->family = i; >>>> >>>> ...because the user specifying the override should know ahead of time >>>> if that family is available, and we should fail the detection >>>> otherwise. >>> >>> It's more complicated when you have a mixture of NVDIMM types, where not all >>> NVDIMMs support the same families. For example, you could have an Intel >>> NVDIMM in the same system as an HPE NVDIMM-N. The reason I called it >>> "default" is because it should be the default for all devices that support >>> that family but I didn't want other types of NVDIMMs to end up with >>> no family at all. >>> >> >> Ok, but I still think we can make the logic a bit simpler. I'm >> reacting to the new "if (i == -1)" branch and 2 locations where we >> call "acpi_check_dsm()". How about this to centralize everything? >> >> @@ -1397,11 +1397,15 @@ static int acpi_nfit_add_dimm(struct >> acpi_nfit_desc *acpi_desc, >> * tells us if any commands are reachable through this uuid. >> */ >> for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_MSFT; i++) >> - if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1)) >> - break; >> + if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1)) { >> + if (family < 0 || i == default_dsm_family) { >> + family = i; >> + break; > > This actually doesn't work with the break since the for() will break > on the first match, just like the current code. It works if I remove > the break, but then we cycle through all the families even if the > default_dsm_family parameter isn't used. Do you care about that? > > I think it can be simple or efficient but not both. Something like this does work. for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_MSFT; i++) if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1)) { if (default_dsm_family != -1) { if (i == default_dsm_family) { family = i; break; } if (family < 0) family = i; } else { family = i; break; } } > > -- ljk >> + } >> + } >> >> /* limit the supported commands to those that are publicly documented */ >> - nfit_mem->family = i; >> + nfit_mem->family = family; >> if (nfit_mem->family == NVDIMM_FAMILY_INTEL) { >> dsm_mask = 0x3fe; >> if (disable_vendor_specific) >> > _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm