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Mon, 15 Dec 2025 12:31:50 +0100 Message-ID: <346cc6d1-b2a5-4088-81a6-99c56c2bd4a6@pengutronix.de> Date: Mon, 15 Dec 2025 12:31:50 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Sascha Hauer , BAREBOX References: <20251209-devfs-v2-0-62ae16698cff@pengutronix.de> <20251209-devfs-v2-12-62ae16698cff@pengutronix.de> From: Ahmad Fatoum Content-Language: en-US, de-DE, de-BE In-Reply-To: <20251209-devfs-v2-12-62ae16698cff@pengutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251215_033152_860944_FBA6F55C X-CRM114-Status: GOOD ( 31.64 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.0 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH v2 12/13] fs: replace cdev links with aliases X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Hi, On 12/9/25 1:51 PM, Sascha Hauer wrote: A commit message would be grand. :) > Signed-off-by: Sascha Hauer Acked-by: Ahmad Fatoum > --- > commands/devinfo.c | 7 +- > common/partitions.c | 2 +- > drivers/block/dm/dm-core.c | 1 - > drivers/misc/storage-by-alias.c | 2 +- > fs/devfs-core.c | 191 +++++++++++++++++++++------------------- > include/block.h | 2 - > include/driver.h | 20 +++-- > 7 files changed, 121 insertions(+), 104 deletions(-) > > diff --git a/commands/devinfo.c b/commands/devinfo.c > index c87b30e84307e5053bc35e8bd70ac7af63f688b8..c5417cb7bbe9c7beacd85888fb34405bdc279aea 100644 > --- a/commands/devinfo.c > +++ b/commands/devinfo.c > @@ -9,7 +9,8 @@ > static int do_devinfo_subtree(struct device *dev, int depth) > { > struct device *child; > - struct cdev *cdev, *cdevl; > + struct cdev *cdev; > + struct cdev_alias *alias; > int i; > > for (i = 0; i < depth; i++) > @@ -26,8 +27,8 @@ static int do_devinfo_subtree(struct device *dev, int depth) > cdev->offset + cdev->size - 1, > size_human_readable(cdev->size), > cdev->name); > - list_for_each_entry(cdevl, &cdev->links, link_entry) > - printf(", %s", cdevl->name); > + cdev_for_each_alias(alias, cdev) > + printf(", %s", alias->name); > printf("\n"); > } > } else { > diff --git a/common/partitions.c b/common/partitions.c > index 7563cb0e6767891ee7f1fe264ce86703408f790a..1a4e046c5f55314ccb2abf5094b0966def8c5b55 100644 > --- a/common/partitions.c > +++ b/common/partitions.c > @@ -63,7 +63,7 @@ static int register_one_partition(struct block_device *blk, struct partition *pa > return 0; > > partition_name = xasprintf("%s.%s", blk->cdev.name, part->name); > - ret = devfs_create_link(cdev, partition_name); > + ret = devfs_add_alias(cdev, partition_name); > if (ret) > dev_warn(blk->dev, "Failed to create link from %s to %s\n", > partition_name, cdev->name); > diff --git a/drivers/block/dm/dm-core.c b/drivers/block/dm/dm-core.c > index fd7ed0d84ed7388f8c1cd4aa19e0466191459fd6..2f48cfeb06f7b2da6d26850820f228a6f522fc2f 100644 > --- a/drivers/block/dm/dm-core.c > +++ b/drivers/block/dm/dm-core.c > @@ -77,7 +77,6 @@ int dm_cdev_open(struct dm_cdev *dmcdev, const char *path, ulong flags, > return -ENODEV; > } > > - dmcdev->cdev = cdev_readlink(dmcdev->cdev); > break; > default: > *errmsg = xstrdup("Only regular files and device specials are supported"); > diff --git a/drivers/misc/storage-by-alias.c b/drivers/misc/storage-by-alias.c > index 6c759867ccbb7a7b4bc922152699eb346d42d271..196346c8eafcc7868aa279353414409617e1e907 100644 > --- a/drivers/misc/storage-by-alias.c > +++ b/drivers/misc/storage-by-alias.c > @@ -38,7 +38,7 @@ static int sba_add_partitions(struct cdev *rcdev, void *data) > > dev_info(sba->dev, "Adding %s -> %s\n", sba->alias, rcdev->name); > > - ret = devfs_create_link_node(rcdev, sba->alias, sba->dev->device_node); > + ret = devfs_add_alias_node(rcdev, sba->alias, sba->dev->device_node); > if (ret) > return ret; > > diff --git a/fs/devfs-core.c b/fs/devfs-core.c > index 3a5667b9f723fa718453bdc58827f4b760f3565a..b285b7ede029b14bb0bbc1dbf60ba8a8895c3f26 100644 > --- a/fs/devfs-core.c > +++ b/fs/devfs-core.c > @@ -50,42 +50,21 @@ int devfs_partition_complete(struct string_list *sl, char *instr) > } > #endif > > -struct cdev *cdev_readlink(const struct cdev *cdev) > -{ > - if (!cdev) > - return NULL; > - > - if (cdev->link) > - cdev = cdev->link; > - > - /* links to links are not allowed */ > - BUG_ON(cdev->link); > - > - return (void *)cdev; > -} > - > -struct cdev *lcdev_by_name(const char *filename) > +struct cdev *cdev_by_name(const char *filename) > { > struct cdev *cdev; > + struct cdev_alias *alias; > > for_each_cdev(cdev) { > if (!strcmp(cdev->name, filename)) > return cdev; > + cdev_for_each_alias(alias, cdev) > + if (!strcmp(alias->name, filename)) > + return cdev; > } > return NULL; > } > > -struct cdev *cdev_by_name(const char *filename) > -{ > - struct cdev *cdev; > - > - cdev = lcdev_by_name(filename); > - if (!cdev) > - return NULL; > - > - return cdev_readlink(cdev); > -} > - > struct cdev *cdev_by_device_node(struct device_node *node) > { > struct cdev *cdev; > @@ -94,8 +73,14 @@ struct cdev *cdev_by_device_node(struct device_node *node) > return NULL; > > for_each_cdev(cdev) { > + struct cdev_alias *alias; > + > if (cdev_of_node(cdev) == node) > - return cdev_readlink(cdev); > + return cdev; > + > + cdev_for_each_alias(alias, cdev) > + if (alias->device_node == node) > + return cdev; > } > return NULL; > } > @@ -133,9 +118,6 @@ cdev_find_child_by_gpt_typeuuid(struct cdev *cdev, const guid_t *typeuuid) > { > struct cdev *partcdev; > > - /* Follow links to support storage-by-alias */ > - cdev = cdev_readlink(cdev); > - > if (!cdev_is_gpt_partitioned(cdev)) > return ERR_PTR(-EINVAL); > > @@ -153,6 +135,29 @@ cdev_find_child_by_gpt_typeuuid(struct cdev *cdev, const guid_t *typeuuid) > return ERR_PTR(-ENOENT); > } > > +static bool cdev_has_partname_alias(struct cdev *cdev, const char *partname) > +{ > + char *fullname; > + struct cdev_alias *alias; > + bool ret = false; > + > + if (!cdev->master) > + return false; > + > + fullname = xasprintf("%s.%s", cdev->master->name, partname); > + > + cdev_for_each_alias(alias, cdev) { > + if (streq_ptr(alias->name, fullname)) { > + ret = true; > + break; > + } > + } > + > + free(fullname); > + > + return ret; > +} > + > /** > * cdev_find_partition - find a partition belonging to a physical device > * > @@ -164,15 +169,10 @@ struct cdev *cdev_find_partition(struct cdev *cdevm, const char *name) > struct cdev *partcdev; > > for_each_cdev_partition(partcdev, cdevm) { > - struct cdev *cdevl; > - > if (streq_ptr(partcdev->partname, name)) > return partcdev; > - > - list_for_each_entry(cdevl, &partcdev->links, link_entry) { > - if (streq_ptr(cdevl->partname, name)) > - return cdevl; > - } > + if (cdev_has_partname_alias(partcdev, name)) > + return partcdev; > } > > return NULL; > @@ -190,15 +190,11 @@ struct cdev *device_find_partition(struct device *dev, const char *name) > struct device *child; > > list_for_each_entry(cdev, &dev->cdevs, devices_list) { > - struct cdev *cdevl; > - > if (streq_ptr(cdev->partname, name)) > return cdev; > > - list_for_each_entry(cdevl, &cdev->links, link_entry) { > - if (streq_ptr(cdevl->partname, name)) > - return cdev_readlink(cdevl); > - } > + if (cdev_has_partname_alias(cdev, name)) > + return cdev; > } > > device_for_each_child(dev, child) { > @@ -460,25 +456,54 @@ static void cdev_free(struct cdev *cdev) > > static bool devfs_initialized; > > +static int cdev_symlink(struct cdev *cdev, const char *linkname) > +{ > + char *path; > + int ret; > + > + if (!devfs_initialized) > + return 0; > + > + path = xasprintf("/dev/%s", linkname); > + ret = symlink(cdev->name, path); > + free(path); > + > + return ret; > +} > + > static void devfs_mknod(struct cdev *cdev) > { > char *path; > int ret; > + struct cdev_alias *alias; > > if (!devfs_initialized) > return; > > path = xasprintf("/dev/%s", cdev->name); > > - if (cdev->link) > - ret = symlink(cdev->link->name, path); > - else > - ret = mknod(path, S_IFCHR | 0600, cdev->name); > + cdev_for_each_alias(alias, cdev) > + cdev_symlink(cdev, alias->name); > + > + ret = mknod(path, S_IFCHR | 0600, cdev->name); > > free(path); > > - if (ret) > + if (ret) { > pr_err("Failed to create /dev/%s: %pe\n", cdev->name, ERR_PTR(ret)); > + dump_stack(); > + } > +} > + > +static void devfs_unlink(const char *name) > +{ > + char *path; > + > + path = xasprintf("/dev/%s", name); > + > + unlink(path); > + > + free(path); > } > > void devfs_init(void) > @@ -499,8 +524,8 @@ int devfs_create(struct cdev *new) > if (cdev) > return -EEXIST; > > - INIT_LIST_HEAD(&new->links); > INIT_LIST_HEAD(&new->partitions); > + INIT_LIST_HEAD(&new->aliases); > > list_add_tail(&new->list, &cdev_list); > if (new->dev) { > @@ -509,54 +534,44 @@ int devfs_create(struct cdev *new) > new->device_node = new->dev->of_node; > } > > - if (new->link) > - list_add_tail(&new->link_entry, &new->link->links); > - > devfs_mknod(new); > > return 0; > } > > -int devfs_create_link_node(struct cdev *cdev, const char *name, struct device_node *node) > +int devfs_add_alias_node(struct cdev *cdev, const char *name, struct device_node *np) > { > - struct cdev *new; > - int ret; > - > - /* > - * Create a link to the real cdev instead of creating > - * a link to a link. > - */ > - cdev = cdev_readlink(cdev); > - > - new = cdev_alloc(name); > - new->link = cdev; > - new->device_node = node; > - > - ret = devfs_create(new); > - if (ret) { > - cdev_free(new); > - return ret; > - } > - > - if (cdev->partname) { > - size_t partnameoff = 0; > + struct cdev *conflict; > + struct cdev_alias *alias; > > - if (cdev->master) { > - size_t masterlen = strlen(cdev->master->name); > + conflict = cdev_by_name(name); > + if (conflict) > + return -EEXIST; > > - if (!strncmp(name, cdev->master->name, masterlen)) > - partnameoff += masterlen + 1; > - } > + alias = xzalloc(sizeof(*alias)); > + alias->name = xstrdup(name); > + alias->device_node = np; > + list_add_tail(&alias->list, &cdev->aliases); > > - new->partname = xstrdup(name + partnameoff); > - } > + cdev_symlink(cdev, name); > > return 0; > } > > -int devfs_create_link(struct cdev *cdev, const char *name) > +int devfs_add_alias(struct cdev *cdev, const char *name) > +{ > + return devfs_add_alias_node(cdev, name, NULL); > +} > + > +static void devfs_remove_aliases(struct cdev *cdev) > { > - return devfs_create_link_node(cdev, name, NULL); > + struct cdev_alias *alias, *tmp; > + > + list_for_each_entry_safe(alias, tmp, &cdev->aliases, list) { > + devfs_unlink(alias->name); > + free(alias->name); > + free(alias); > + } > } > > int devfs_remove(struct cdev *cdev) > @@ -571,8 +586,9 @@ int devfs_remove(struct cdev *cdev) > if (cdev->dev) > list_del(&cdev->devices_list); > > - list_for_each_entry_safe(c, tmp, &cdev->links, link_entry) > - devfs_remove(c); > + devfs_unlink(cdev->name); > + > + devfs_remove_aliases(cdev); > > list_for_each_entry_safe(c, tmp, &cdev->partitions, partition_entry) > cdevfs_del_partition(c); > @@ -580,9 +596,6 @@ int devfs_remove(struct cdev *cdev) > if (cdev_is_partition(cdev)) > list_del(&cdev->partition_entry); > > - if (cdev->link) > - cdev_free(cdev); > - > return 0; > } > > @@ -687,7 +700,7 @@ static struct cdev *__devfs_add_partition(struct cdev *cdev, > if (overlap) { > if (!IS_ERR(overlap)) { > /* only fails with -EEXIST, which is fine */ > - (void)devfs_create_link(overlap, partinfo->name); > + (void)devfs_add_alias(overlap, partinfo->name); > } > > return overlap; > diff --git a/include/block.h b/include/block.h > index fc7a0a32fb2d6bc579aa6305433fb2a9e39f336a..a8ebe202288fff83677948f3d67bc12cae5dc107 100644 > --- a/include/block.h > +++ b/include/block.h > @@ -104,13 +104,11 @@ static inline bool cdev_is_block_device(const struct cdev *cdev) > > static inline bool cdev_is_block_partition(const struct cdev *cdev) > { > - cdev = cdev_readlink(cdev); > return cdev_is_block_device(cdev) && cdev_is_partition(cdev); > } > > static inline bool cdev_is_block_disk(const struct cdev *cdev) > { > - cdev = cdev_readlink(cdev); > return cdev_is_block_device(cdev) && !cdev_is_partition(cdev); > } > > diff --git a/include/driver.h b/include/driver.h > index 802917f1c20727272364d094552e4e5b40a6165b..1c78f35f7eb960ac231ee6ad20db8a2a7cbb6a19 100644 > --- a/include/driver.h > +++ b/include/driver.h > @@ -17,6 +17,7 @@ > #include > #include > #include > +#include > > #define FORMAT_DRIVER_NAME_ID "%s%d" > > @@ -432,8 +433,7 @@ struct cdev { > u16 typeflags; /* GPT type-specific attributes */ > int open; > struct mtd_info *mtd; > - struct cdev *link; > - struct list_head link_entry, links; > + struct list_head aliases; > struct list_head partition_entry, partitions; > struct cdev *master; > enum filetype filetype; > @@ -443,6 +443,15 @@ struct cdev { > }; > }; > > +#define cdev_for_each_alias(alias, cdev) \ > + list_for_each_entry(alias, &cdev->aliases, list) > + > +struct cdev_alias { > + char *name; > + struct device_node *device_node; > + struct list_head list; > +}; > + > static inline struct device_node *cdev_of_node(const struct cdev *cdev) > { > return IS_ENABLED(CONFIG_OFDEVICE) ? cdev->device_node : NULL; > @@ -461,15 +470,12 @@ static inline const char *cdev_name(struct cdev *cdev) > > void devfs_init(void); > int devfs_create(struct cdev *); > -int devfs_create_link(struct cdev *, const char *name); > -int devfs_create_link_node(struct cdev *cdev, const char *name, > - struct device_node *node); > +int devfs_add_alias(struct cdev *, const char *name); > +int devfs_add_alias_node(struct cdev *, const char *name, struct device_node *np); > int devfs_remove(struct cdev *); > int cdev_find_free_index(const char *); > struct cdev *cdev_find_partition(struct cdev *cdevm, const char *name); > struct cdev *device_find_partition(struct device *dev, const char *name); > -struct cdev *lcdev_by_name(const char *filename); > -struct cdev *cdev_readlink(const struct cdev *cdev); > struct cdev *cdev_by_device_node(struct device_node *node); > struct cdev *cdev_by_partuuid(const char *partuuid); > struct cdev *cdev_by_diskuuid(const char *partuuid); > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |