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X-IronPort-AV: E=McAfee;i="6500,9779,10613"; a="329349462" X-IronPort-AV: E=Sophos;i="5.97,276,1669104000"; d="scan'208";a="329349462" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Feb 2023 14:41:30 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10613"; a="775298862" X-IronPort-AV: E=Sophos;i="5.97,276,1669104000"; d="scan'208";a="775298862" Received: from djiang5-mobl3.amr.corp.intel.com (HELO [10.212.111.195]) ([10.212.111.195]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Feb 2023 14:41:30 -0800 Message-ID: Date: Mon, 6 Feb 2023 15:41:29 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.6.0 Subject: Re: [PATCH 06/18] cxl/region: Refactor attach_target() for autodiscovery Content-Language: en-US To: Dan Williams , linux-cxl@vger.kernel.org Cc: dave.hansen@linux.intel.com, linux-mm@kvack.org, linux-acpi@vger.kernel.org References: <167564534874.847146.5222419648551436750.stgit@dwillia2-xfh.jf.intel.com> <167564538227.847146.16305045998592488364.stgit@dwillia2-xfh.jf.intel.com> From: Dave Jiang In-Reply-To: <167564538227.847146.16305045998592488364.stgit@dwillia2-xfh.jf.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: D7C748001C X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: sdfshhdoq73cb5jjmrp7cc4cig1yx41i X-HE-Tag: 1675723292-237010 X-HE-Meta: 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 l4FZTIR0 KpKHnjkbKVMlfZbcw0XmOo23xOBFYyJOMjy8AeKiKNjX/iipbN91A7DM/Q5cN6NX5v5Sw+OLLSu3Bb+GbBTN1SVAgqNJ4OyfJNeKaicVe3Xofmo3QEkuXmU8PQXL/lrOExYc6FBh6/sUvwRCqg57bdiUghSGds2LvsdXqMeloYVsuozEHnIIxEtjPQ8wHs4fDMzJNw40lKZgayXNaU5zPMQK1WwL3AiqXWOQ2 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2/5/23 6:03 PM, Dan Williams wrote: > Region autodiscovery is the process of kernel creating 'struct > cxl_region' object to represent active CXL memory ranges it finds > already active in hardware when the driver loads. Typically this happens > when platform firmware establishes CXL memory regions and then publishes > them in the memory map. However, this can also happen in the case of > kexec-reboot after the kernel has created regions. > > In the autodiscovery case the region creation process starts with a > known endpoint decoder. Refactor attach_target() into a helper that is > suitable to be called from either sysfs, for runtime region creation, or > from cxl_port_probe() after it has enumerated all endpoint decoders. > > The cxl_port_probe() context is an async device-core probing context, so > it is not appropriate to allow SIGTERM to interrupt the assembly > process. Refactor attach_target() to take @cxled and @state as arguments > where @state indicates whether waiting from the region rwsem is > interruptible or not. > > No behavior change is intended. > > Signed-off-by: Dan Williams Reviewed-by: Dave Jiang > --- > drivers/cxl/core/region.c | 47 +++++++++++++++++++++++++++------------------ > 1 file changed, 28 insertions(+), 19 deletions(-) > > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index 8dea49c021b8..97eafdd75675 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -1418,31 +1418,25 @@ void cxl_decoder_kill_region(struct cxl_endpoint_decoder *cxled) > up_write(&cxl_region_rwsem); > } > > -static int attach_target(struct cxl_region *cxlr, const char *decoder, int pos) > +static int attach_target(struct cxl_region *cxlr, > + struct cxl_endpoint_decoder *cxled, int pos, > + unsigned int state) > { > - struct device *dev; > - int rc; > - > - dev = bus_find_device_by_name(&cxl_bus_type, NULL, decoder); > - if (!dev) > - return -ENODEV; > - > - if (!is_endpoint_decoder(dev)) { > - put_device(dev); > - return -EINVAL; > - } > + int rc = 0; > > - rc = down_write_killable(&cxl_region_rwsem); > + if (state == TASK_INTERRUPTIBLE) > + rc = down_write_killable(&cxl_region_rwsem); > + else > + down_write(&cxl_region_rwsem); > if (rc) > - goto out; > + return rc; > + > down_read(&cxl_dpa_rwsem); > - rc = cxl_region_attach(cxlr, to_cxl_endpoint_decoder(dev), pos); > + rc = cxl_region_attach(cxlr, cxled, pos); > if (rc == 0) > set_bit(CXL_REGION_F_INCOHERENT, &cxlr->flags); > up_read(&cxl_dpa_rwsem); > up_write(&cxl_region_rwsem); > -out: > - put_device(dev); > return rc; > } > > @@ -1480,8 +1474,23 @@ static size_t store_targetN(struct cxl_region *cxlr, const char *buf, int pos, > > if (sysfs_streq(buf, "\n")) > rc = detach_target(cxlr, pos); > - else > - rc = attach_target(cxlr, buf, pos); > + else { > + struct device *dev; > + > + dev = bus_find_device_by_name(&cxl_bus_type, NULL, buf); > + if (!dev) > + return -ENODEV; > + > + if (!is_endpoint_decoder(dev)) { > + rc = -EINVAL; > + goto out; > + } > + > + rc = attach_target(cxlr, to_cxl_endpoint_decoder(dev), pos, > + TASK_INTERRUPTIBLE); > +out: > + put_device(dev); > + } > > if (rc < 0) > return rc; >