Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753877AbbL3IvR (ORCPT ); Wed, 30 Dec 2015 03:51:17 -0500 Received: from mail-wm0-f50.google.com ([74.125.82.50]:34769 "EHLO mail-wm0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751668AbbL3IvO convert rfc822-to-8bit (ORCPT ); Wed, 30 Dec 2015 03:51:14 -0500 Subject: Re: [PATCH] configfs: implement binary attributes Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) Content-Type: text/plain; charset=utf-8 From: Pantelis Antoniou In-Reply-To: <20151229230029.GC32415@noexit.roam.corp.google.com> Date: Wed, 30 Dec 2015 10:51:08 +0200 Cc: Christoph Hellwig , Andrew Morton , Nicholas Bellinger , k.opasiak@samsung.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8BIT Message-Id: <2BCD0159-9633-48D3-95B4-ED9631F182B7@konsulko.com> References: <1450968671-13699-1-git-send-email-hch@lst.de> <1450968671-13699-2-git-send-email-hch@lst.de> <20151229230029.GC32415@noexit.roam.corp.google.com> To: Joel Becker X-Mailer: Apple Mail (2.2104) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2816 Lines: 94 Hi Joel, > On Dec 30, 2015, at 01:00 , Joel Becker wrote: > > On Thu, Dec 24, 2015 at 03:51:10PM +0100, Christoph Hellwig wrote: >> From: Pantelis Antoniou >> >> ConfigFS lacked binary attributes up until now. This patch >> introduces support for binary attributes in a somewhat similar >> manner of sysfs binary attributes albeit with changes that >> fit the configfs usage model. >> >> Problems that configfs binary attributes fix are everything that >> requires a binary blob as part of the configuration of a resource, >> such as bitstream loading for FPGAs, DTBs for dynamically created >> devices etc. > > Overall, I really like this addition. > That’s good :) >> @@ -423,7 +429,9 @@ static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * den >> spin_unlock(&configfs_dirent_lock); >> >> error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, >> - configfs_init_file); >> + (sd->s_type & CONFIGFS_ITEM_ATTR) ? >> + configfs_init_file : >> + configfs_init_bin_file); > > BIN_ATTRs are the more uncommon type, at least for now. I would think > this code should check for special cases and fall back to ITEM_ATTR. So > reverse it. > > (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) ? > configfs_init_bin_file : > configfs_init_file > OK. >> +static ssize_t >> +configfs_read_bin_file(struct file *file, char __user *buf, >> + size_t count, loff_t *ppos) >> +{ >> + struct configfs_buffer *buffer = file->private_data; >> + struct dentry *dentry = file->f_path.dentry; >> + struct config_item *item = to_item(dentry->d_parent); >> + struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry); >> + ssize_t retval = 0; >> + ssize_t len = min_t(size_t, count, PAGE_SIZE); >> + >> + mutex_lock(&buffer->mutex); >> + >> + /* we don't support switching read/write modes */ >> + if (buffer->write_in_progress) { >> + retval = -EINVAL; >> + goto out; >> + } > > These are valid arguments, it's just competing with another operation. > Wouldn't something like EINPROGRESS or ETXTBSY make more sense and be > more informative? The same for configfs_write_bin_file(). > Yep, will be done. > Joel > Regards — Pantelis PS. A big thanks to Christoph for keeping this going. I will shortly post a new version with the requested changes incorporated. > -- > > "Soap and education are not as sudden as a massacre, but they are more > deadly in the long run." > - Mark Twain > > > http://www.jlbec.org/ > jlbec@evilplan.org -- 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/