From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752404AbdCNQKW (ORCPT ); Tue, 14 Mar 2017 12:10:22 -0400 Received: from mga06.intel.com ([134.134.136.31]:1124 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751177AbdCNQKU (ORCPT ); Tue, 14 Mar 2017 12:10:20 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,164,1486454400"; d="scan'208";a="1122433649" Subject: Re: [RFC 1/2] firmware class: Add stream_firmware API. To: matthew.gerlach@linux.intel.com References: <1489105090-4996-1-git-send-email-yi1.li@linux.intel.com> <1489105090-4996-2-git-send-email-yi1.li@linux.intel.com> <7a919967-27a7-ec7a-0669-5dec369af3fb@linux.intel.com> Cc: ming.lei@canonical.com, mcgrof@kernel.org, gregkh@linuxfoundation.org, atull@opensource.altera.com, moritz.fischer@ettus.com, linux-kernel@vger.kernel.org, linux-fpga@vger.kernel.org From: "Li, Yi" Message-ID: Date: Tue, 14 Mar 2017 11:10:12 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org hi Matthew, On 3/13/2017 4:09 PM, matthew.gerlach@linux.intel.com wrote: > > > On Fri, 10 Mar 2017, Li, Yi wrote: > >> Hi Matthew >> > Hi Yi, > > >> >> On 3/10/2017 11:44 AM, matthew.gerlach@linux.intel.com wrote: >>> >>> >>> On Thu, 9 Mar 2017, yi1.li@linux.intel.com wrote: >>> >>>> From: Yi Li >>> >>> >>> Hi Yi, >>> >>> Just one question below. >>> >>> Matthew Gerlach >>> >>> >>>> Add function to load firmware in multiple chucks instead of >>>> >>>> loading the whole big firmware file at once. >>>> >>>> Signed-off-by: Yi Li >>>> --- >>>> drivers/base/firmware_class.c | 128 >>>> ++++++++++++++++++++++++++++++++++++++++++ >>>> include/linux/firmware.h | 2 + >>>> 2 files changed, 130 insertions(+) >>>> >>>> diff --git a/drivers/base/firmware_class.c >>>> b/drivers/base/firmware_class.c >>>> index ac350c5..44fddff 100644 >>>> --- a/drivers/base/firmware_class.c >>>> +++ b/drivers/base/firmware_class.c >>>> @@ -436,6 +436,62 @@ fw_get_filesystem_firmware(struct device >>>> *device, struct firmware_buf *buf) >>>> return rc; >>>> } >>>> >>>> +static int >>>> +fw_stream_filesystem_firmware(struct device *device, struct >>>> firmware_buf *buf, >>>> + size_t offset, size_t length) >>>> +{ >>>> + int i, len; >>>> + char *path; >>>> + int rc = 0; >>>> + struct file *file; >>>> + >>>> + buf->size = 0; >>>> + >>>> + path = __getname(); >>>> + if (!path) >>>> + return -ENOMEM; >>>> + >>>> + for (i = 0; i < ARRAY_SIZE(fw_path); i++) { >>>> + /* skip the unset customized path */ >>>> + if (!fw_path[i][0]) >>>> + continue; >>>> + >>>> + len = snprintf(path, PATH_MAX, "%s/%s", >>>> + fw_path[i], buf->fw_id); >>> >>> I'm probably being paranoid, but is it safe to assume the length of >>> the buffer returned by __getname() is at least PATH_MAX? It seems like >>> the length should be pagesize. >> >> The size should be the maximum number of char of the string be >> produced, not the input size. >> According to >> https://www.gnu.org/software/libc/manual/html_node/Formatted-Output-Functions.html >> Function:/int/*snprintf*/(char *s, size_tsize, const char *template, …) >> /The|snprintf|function is similar to|sprintf|, except that >> thesizeargument specifies the maximum number of characters to >> produce. The trailing null character is counted towards this limit, >> so you should allocate at leastsizecharacters for the strings. >> Ifsizeis zero, nothing, not even the null byte, shall be written >> andsmay be a null pointer. >> The return value is the number of characters which would be generated >> for the given input, excluding the trailing null. If this value is >> greater than or equal tosize, not all characters from the result have >> been stored ins >> > > I am familiar with the functionality of snprintf versus sprintf. In the > snprintf call above, you are saying that memory pointed to by the > variable path, has at least PATH_MAX number of bytes. My question is > how can you know that the memory returned by __getname() has PATH_MAX > number of bytes? > > Ah, now I understand the concerns. The __getname() will allocate an buffer object from names_cachep extern struct kmem_cache *names_cachep ; #define __getname () kmem_cache_alloc (names_cachep , GFP_KERNEL ) names_cachep is created in fs/dcaches.c vfs_caches_init function with object size equal to PATH_MAX. names_cachep = kmem_cache_create (/"names_cache"/, PATH_MAX , 0,SLAB_HWCACHE_ALIGN |SLAB_PANIC , NULL ); so __getname() should allocate buffer with size of PATH_MAX. The code is borrowed from fw_get_filesystem_firmware function, which should be reviewed and safe to use. :) Thanks, Yi >>> >>>> + if (len >= PATH_MAX) { >>>> + rc = -ENAMETOOLONG; >>>> + break; >>>> + } >>>> + >>>> + if (!path || !*path) >>>> + continue; >>>> + >>>> + if (!buf->data) { >>>> + buf->data = vmalloc(length); >>>> + if (!buf->data) { >>>> + rc = -ENOMEM; >>>> + break; >>>> + } >>>> + } >>>> + >>>> + file = filp_open(path, O_RDONLY, 0); >>>> + if (IS_ERR(file)) >>>> + continue; >>>> + >>>> + buf->size = kernel_read(file, offset, (char *) buf->data, >>>> + length); >>>> + fput(file); >>>> + break; >>>> + } >>>> + >>>> + __putname(path); >>>> + >>>> + if (rc) >>>> + dev_err(device, "loading %s failed with error %d\n", >>>> + path, rc); >>>> + return rc; >>>> +} >>>> + >>>> /* firmware holds the ownership of pages */ >>>> static void firmware_free_data(const struct firmware *fw) >>>> { >>>> @@ -1267,6 +1323,78 @@ request_firmware(const struct firmware >>>> **firmware_p, const char *name, >>>> } >>>> EXPORT_SYMBOL(request_firmware); >>>> >>>> +static int >>>> +_stream_firmware(const struct firmware **firmware_p, const char >>>> *name, >>>> + struct device *device, void *buf, size_t size, >>>> + unsigned int opt_flags, size_t offset, size_t length) >>>> +{ >>>> + int ret; >>>> + struct firmware *fw = NULL; >>>> + struct firmware_buf *fbuf; >>>> + >>>> + if ((!firmware_p) || (!name || name[0] == '\0')) { >>>> + dev_err(device, "invalid firmware pointer or file name\n"); >>>> + return -EINVAL; >>>> + } >>>> + >>>> + if (!*firmware_p) { >>>> + ret = _request_firmware_prepare(&fw, name, device, buf, >>>> size); >>>> + if (ret <= 0) { >>>> + dev_err(device, "%s: _request_firmware_prepare failed >>>> %d\n", >>>> + __func__, ret); >>>> + } >>>> + } else { >>>> + fw = (struct firmware *) *firmware_p; >>>> + } >>>> + >>>> + fbuf = (struct firmware_buf *) fw->priv; >>>> + ret = fw_stream_filesystem_firmware(device, fbuf, offset, >>>> length); >>>> + fw->size = fbuf->size; >>>> + fw->data = fbuf->data; >>>> + *firmware_p = fw; >>>> + >>>> + if (ret) >>>> + dev_err(device, "streaming with error %d\n", ret); >>>> + return ret; >>>> +} >>>> + >>>> +/** >>>> + * stream_firmware: - send firmware request and wait for it >>>> + * @firmware_p: pointer to firmware image >>>> + * @name: name of firmware file >>>> + * @device: device for which firmware is being loaded >>>> + * @offset: offset of the file to read from >>>> + * @length: length in bytes to read >>>> + * >>>> + * @firmware_p will be used to return a firmware image by the >>>> name >>>> + * of @name for device @device. >>>> + * >>>> + * Should be called from user context where sleeping is allowed. >>>> + * >>>> + * @name will be used as $FIRMWARE in the uevent environment and >>>> + * should be distinctive enough not to be confused with any >>>> other >>>> + * firmware image for this or any other device. >>>> + * >>>> + * Caller must hold the reference count of @device. >>>> + * >>>> + * The function can be called safely inside device's suspend and >>>> + * resume callback. >>>> + **/ >>>> +int >>>> +stream_firmware(const struct firmware **firmware_p, const char *name, >>>> + struct device *device, size_t offset, size_t length) >>>> +{ >>>> + size_t ret; >>>> + >>>> + /* Need to pin this module until return */ >>>> + __module_get(THIS_MODULE); >>>> + ret = _stream_firmware(firmware_p, name, device, NULL, 0, >>>> + FW_OPT_UEVENT | FW_OPT_NO_WARN, offset, length); >>>> + module_put(THIS_MODULE); >>>> + return ret; >>>> +} >>>> +EXPORT_SYMBOL(stream_firmware); >>>> + >>>> /** >>>> * request_firmware_direct: - load firmware directly without >>>> usermode helper >>>> * @firmware_p: pointer to firmware image >>>> diff --git a/include/linux/firmware.h b/include/linux/firmware.h >>>> index b1f9f0c..accd7f6 100644 >>>> --- a/include/linux/firmware.h >>>> +++ b/include/linux/firmware.h >>>> @@ -41,6 +41,8 @@ struct builtin_fw { >>>> #if defined(CONFIG_FW_LOADER) || (defined(CONFIG_FW_LOADER_MODULE) >>>> && defined(MODULE)) >>>> int request_firmware(const struct firmware **fw, const char *name, >>>> struct device *device); >>>> +int stream_firmware(const struct firmware **fw, const char *name, >>>> + struct device *device, size_t offset, size_t length); >>>> int request_firmware_nowait( >>>> struct module *module, bool uevent, >>>> const char *name, struct device *device, gfp_t gfp, void *context, >>>> -- >>>> 2.7.4 >>>> >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe >>>> linux-fpga" in >>>> the body of a message to majordomo@vger.kernel.org >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-fpga" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >>