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[90.8.158.167]) by smtp.gmail.com with ESMTPSA id j6sm5501305wmq.16.2021.03.09.12.59.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Mar 2021 12:59:36 -0800 (PST) From: Bartosz Golaszewski To: Joel Becker , Christoph Hellwig , Shuah Khan , Linus Walleij , Andy Shevchenko , =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= , Geert Uytterhoeven , Kent Gibson , Jonathan Corbet , Greg Kroah-Hartman Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH v3 04/11] samples: configfs: add a committable group Date: Tue, 9 Mar 2021 21:59:14 +0100 Message-Id: <20210309205921.15992-5-brgl@bgdev.pl> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210309205921.15992-1-brgl@bgdev.pl> References: <20210309205921.15992-1-brgl@bgdev.pl> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org From: Bartosz Golaszewski Add an example of using committable items to configfs samples. Each config item has two attributes: read-write 'storeme' which works similarly to other examples in this file and a read-only 'committed' attribute which changes its value between false and true depending on whether it's committed or not at the moment. Signed-off-by: Bartosz Golaszewski Acked-by: Linus Walleij --- samples/configfs/configfs_sample.c | 153 +++++++++++++++++++++++++++++ 1 file changed, 153 insertions(+) diff --git a/samples/configfs/configfs_sample.c b/samples/configfs/configfs_sample.c index f9008be7a8a1..9bef74e4369d 100644 --- a/samples/configfs/configfs_sample.c +++ b/samples/configfs/configfs_sample.c @@ -315,6 +315,158 @@ static struct configfs_subsystem group_children_subsys = { /* ----------------------------------------------------------------- */ +/* + * 04-committable-children + * + * This is an example of a committable group. It's similar to the simple + * children example but each config_item has an additional 'committed' + * attribute which is read-only and is only modified when the config_item + * is moved from the 'pending' to the 'live' directory. + */ + +struct committable_child { + struct config_item item; + int storeme; + bool committed; +}; + +static inline struct committable_child * +to_committable_child(struct config_item *item) +{ + return container_of(item, struct committable_child, item); +} + +static ssize_t +committable_child_storeme_show(struct config_item *item, char *page) +{ + return sprintf(page, "%d\n", to_committable_child(item)->storeme); +} + +static ssize_t committable_child_storeme_store(struct config_item *item, + const char *page, size_t count) +{ + struct committable_child *child = to_committable_child(item); + int ret; + + if (child->committed) + return -EPERM; + + ret = kstrtoint(page, 10, &child->storeme); + if (ret) + return ret; + + return count; +} + +CONFIGFS_ATTR(committable_child_, storeme); + +static ssize_t +committable_child_committed_show(struct config_item *item, char *page) +{ + return sprintf(page, "%s\n", + to_committable_child(item)->committed ? "true" : "false"); +} + +CONFIGFS_ATTR_RO(committable_child_, committed); + +static struct configfs_attribute *committable_child_attrs[] = { + &committable_child_attr_storeme, + &committable_child_attr_committed, + NULL, +}; + +static void committable_child_release(struct config_item *item) +{ + kfree(to_committable_child(item)); +} + +static struct configfs_item_operations committable_child_item_ops = { + .release = committable_child_release, +}; + +static const struct config_item_type committable_child_type = { + .ct_item_ops = &committable_child_item_ops, + .ct_attrs = committable_child_attrs, + .ct_owner = THIS_MODULE, +}; + +struct committable_children { + struct config_group group; +}; + +static struct config_item * +committable_children_make_item(struct config_group *group, const char *name) +{ + struct committable_child *child; + + child = kzalloc(sizeof(*child), GFP_KERNEL); + if (!child) + return ERR_PTR(-ENOMEM); + + config_item_init_type_name(&child->item, name, &committable_child_type); + + return &child->item; +} + +static ssize_t +committable_children_description_show(struct config_item *item, char *page) +{ + return sprintf(page, +"[04-committable-children]\n" +"\n" +"This subsystem allows creation of committable config_items. The subsystem\n" +"has two subdirectories: pending and live. New config_items can only be\n" +"created in pending/ and they have one writable and readable attribute as\n" +"well as a single read-only attribute. The latter is only changed once the\n" +"item is 'committed'. This is done by moving the config_item (using\n" +"rename()) to the live/ directory. In this example, the storeme attribute\n" +"becomes 'read-only' once committed.\n"); +} + +CONFIGFS_ATTR_RO(committable_children_, description); + +static struct configfs_attribute *committable_children_attrs[] = { + &committable_children_attr_description, + NULL, +}; + +static int committable_children_commit_item(struct config_item *item) +{ + to_committable_child(item)->committed = true; + + return 0; +} + +static int committable_children_uncommit_item(struct config_item *item) +{ + to_committable_child(item)->committed = false; + + return 0; +} + +static struct configfs_group_operations committable_children_group_ops = { + .make_item = committable_children_make_item, + .commit_item = committable_children_commit_item, + .uncommit_item = committable_children_uncommit_item, +}; + +static const struct config_item_type committable_children_type = { + .ct_group_ops = &committable_children_group_ops, + .ct_attrs = committable_children_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct configfs_subsystem committable_children_subsys = { + .su_group = { + .cg_item = { + .ci_namebuf = "04-committable-children", + .ci_type = &committable_children_type, + }, + }, +}; + +/* ----------------------------------------------------------------- */ + /* * We're now done with our subsystem definitions. * For convenience in this module, here's a list of them all. It @@ -326,6 +478,7 @@ static struct configfs_subsystem *example_subsys[] = { &childless_subsys.subsys, &simple_children_subsys, &group_children_subsys, + &committable_children_subsys, NULL, };