From 12c92098932b4bbf38396e9aed0a343d35437a21 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 12 Jan 2025 08:06:49 +0000 Subject: debugfs: allow to store an additional opaque pointer at file creation Set by debugfs_create_file_aux(name, mode, parent, data, aux, fops). Plain debugfs_create_file() has it set to NULL. Accessed by debugfs_get_aux(file). Convenience macros for numeric opaque data - debugfs_create_file_aux_num and debugfs_get_aux_num, resp. Signed-off-by: Al Viro Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20250112080705.141166-5-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman --- include/linux/debugfs.h | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) (limited to 'include/linux/debugfs.h') diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index 59444b495d49..7c97417d73b5 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -79,9 +79,11 @@ struct debugfs_short_fops { struct dentry *debugfs_create_file_full(const char *name, umode_t mode, struct dentry *parent, void *data, + const void *aux, const struct file_operations *fops); struct dentry *debugfs_create_file_short(const char *name, umode_t mode, struct dentry *parent, void *data, + const void *aux, const struct debugfs_short_fops *fops); /** @@ -126,7 +128,15 @@ struct dentry *debugfs_create_file_short(const char *name, umode_t mode, const struct debugfs_short_fops *: debugfs_create_file_short, \ struct file_operations *: debugfs_create_file_full, \ struct debugfs_short_fops *: debugfs_create_file_short) \ - (name, mode, parent, data, fops) + (name, mode, parent, data, NULL, fops) + +#define debugfs_create_file_aux(name, mode, parent, data, aux, fops) \ + _Generic(fops, \ + const struct file_operations *: debugfs_create_file_full, \ + const struct debugfs_short_fops *: debugfs_create_file_short, \ + struct file_operations *: debugfs_create_file_full, \ + struct debugfs_short_fops *: debugfs_create_file_short) \ + (name, mode, parent, data, aux, fops) struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, struct dentry *parent, void *data, @@ -153,6 +163,7 @@ void debugfs_remove(struct dentry *dentry); void debugfs_lookup_and_remove(const char *name, struct dentry *parent); const struct file_operations *debugfs_real_fops(const struct file *filp); +const void *debugfs_get_aux(const struct file *file); int debugfs_file_get(struct dentry *dentry); void debugfs_file_put(struct dentry *dentry); @@ -259,6 +270,14 @@ static inline struct dentry *debugfs_lookup(const char *name, return ERR_PTR(-ENODEV); } +static inline struct dentry *debugfs_create_file_aux(const char *name, + umode_t mode, struct dentry *parent, + void *data, void *aux, + const void *fops) +{ + return ERR_PTR(-ENODEV); +} + static inline struct dentry *debugfs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const void *fops) @@ -312,6 +331,7 @@ static inline void debugfs_lookup_and_remove(const char *name, { } const struct file_operations *debugfs_real_fops(const struct file *filp); +void *debugfs_get_aux(const struct file *file); static inline int debugfs_file_get(struct dentry *dentry) { @@ -452,6 +472,11 @@ static inline ssize_t debugfs_read_file_str(struct file *file, #endif +#define debugfs_create_file_aux_num(name, mode, parent, data, n, fops) \ + debugfs_create_file_aux(name, mode, parent, data, \ + (void *)(unsigned long)n, fops) +#define debugfs_get_aux_num(f) (unsigned long)debugfs_get_aux(f) + /** * debugfs_create_xul - create a debugfs file that is used to read and write an * unsigned long value, formatted in hexadecimal -- cgit v1.3 From d1433c7ba289319983ec0086dd22524721a797ef Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 12 Jan 2025 08:06:50 +0000 Subject: debugfs: take debugfs_short_fops definition out of ifdef Signed-off-by: Al Viro Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20250112080705.141166-6-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman --- include/linux/debugfs.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux/debugfs.h') diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index 7c97417d73b5..68e9c6cbd835 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -67,16 +67,16 @@ static const struct file_operations __fops = { \ typedef struct vfsmount *(*debugfs_automount_t)(struct dentry *, void *); -#if defined(CONFIG_DEBUG_FS) - -struct dentry *debugfs_lookup(const char *name, struct dentry *parent); - struct debugfs_short_fops { ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); loff_t (*llseek) (struct file *, loff_t, int); }; +#if defined(CONFIG_DEBUG_FS) + +struct dentry *debugfs_lookup(const char *name, struct dentry *parent); + struct dentry *debugfs_create_file_full(const char *name, umode_t mode, struct dentry *parent, void *data, const void *aux, -- cgit v1.3 From f7862dfef6612b87b2ad8352c4d73886f09456d6 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 12 Jan 2025 08:07:05 +0000 Subject: saner replacement for debugfs_rename() Existing primitive has several problems: 1) calling conventions are clumsy - it returns a dentry reference that is either identical to its second argument or is an ERR_PTR(-E...); in both cases no refcount changes happen. Inconvenient for users and bug-prone; it would be better to have it return 0 on success and -E... on failure. 2) it allows cross-directory moves; however, no such caller have ever materialized and considering the way debugfs is used, it's unlikely to happen in the future. What's more, any such caller would have fun issues to deal with wrt interplay with recursive removal. It also makes the calling conventions clumsier... 3) tautological rename fails; the callers have no race-free way to deal with that. 4) new name must have been formed by the caller; quite a few callers have it done by sprintf/kasprintf/etc., ending up with considerable boilerplate. Proposed replacement: int debugfs_change_name(dentry, fmt, ...). All callers convert to that easily, and it's simpler internally. IMO debugfs_rename() should go; if we ever get a real-world use case for cross-directory moves in debugfs, we can always look into the right way to handle that. Signed-off-by: Al Viro Link: https://lore.kernel.org/r/20250112080705.141166-21-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman --- Documentation/filesystems/debugfs.rst | 12 +-- drivers/net/bonding/bond_debugfs.c | 9 +- drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c | 19 +--- drivers/net/ethernet/marvell/skge.c | 5 +- drivers/net/ethernet/marvell/sky2.c | 5 +- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 +- drivers/opp/debugfs.c | 10 +- fs/debugfs/inode.c | 106 ++++++++++------------ include/linux/debugfs.h | 9 +- mm/shrinker_debug.c | 16 +--- net/hsr/hsr_debugfs.c | 9 +- net/mac80211/debugfs_netdev.c | 11 +-- net/wireless/core.c | 5 +- 13 files changed, 77 insertions(+), 145 deletions(-) (limited to 'include/linux/debugfs.h') diff --git a/Documentation/filesystems/debugfs.rst b/Documentation/filesystems/debugfs.rst index dc35da8b8792..f7f977ffbf8d 100644 --- a/Documentation/filesystems/debugfs.rst +++ b/Documentation/filesystems/debugfs.rst @@ -211,18 +211,16 @@ seq_file content. There are a couple of other directory-oriented helper functions:: - struct dentry *debugfs_rename(struct dentry *old_dir, - struct dentry *old_dentry, - struct dentry *new_dir, - const char *new_name); + struct dentry *debugfs_change_name(struct dentry *dentry, + const char *fmt, ...); struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, const char *target); -A call to debugfs_rename() will give a new name to an existing debugfs -file, possibly in a different directory. The new_name must not exist prior -to the call; the return value is old_dentry with updated information. +A call to debugfs_change_name() will give a new name to an existing debugfs +file, always in the same directory. The new_name must not exist prior +to the call; the return value is 0 on success and -E... on failuer. Symbolic links can be created with debugfs_create_symlink(). There is one important thing that all debugfs users must take into account: diff --git a/drivers/net/bonding/bond_debugfs.c b/drivers/net/bonding/bond_debugfs.c index b19492a7f6ad..8adbec7c5084 100644 --- a/drivers/net/bonding/bond_debugfs.c +++ b/drivers/net/bonding/bond_debugfs.c @@ -63,13 +63,8 @@ void bond_debug_unregister(struct bonding *bond) void bond_debug_reregister(struct bonding *bond) { - struct dentry *d; - - d = debugfs_rename(bonding_debug_root, bond->debug_dir, - bonding_debug_root, bond->dev->name); - if (!IS_ERR(d)) { - bond->debug_dir = d; - } else { + int err = debugfs_change_name(bond->debug_dir, "%s", bond->dev->name); + if (err) { netdev_warn(bond->dev, "failed to reregister, so just unregister old one\n"); bond_debug_unregister(bond); } diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c b/drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c index b0a6c96b6ef4..b35808d3d07f 100644 --- a/drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c +++ b/drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c @@ -505,21 +505,6 @@ void xgbe_debugfs_exit(struct xgbe_prv_data *pdata) void xgbe_debugfs_rename(struct xgbe_prv_data *pdata) { - char *buf; - - if (!pdata->xgbe_debugfs) - return; - - buf = kasprintf(GFP_KERNEL, "amd-xgbe-%s", pdata->netdev->name); - if (!buf) - return; - - if (!strcmp(pdata->xgbe_debugfs->d_name.name, buf)) - goto out; - - debugfs_rename(pdata->xgbe_debugfs->d_parent, pdata->xgbe_debugfs, - pdata->xgbe_debugfs->d_parent, buf); - -out: - kfree(buf); + debugfs_change_name(pdata->xgbe_debugfs, + "amd-xgbe-%s", pdata->netdev->name); } diff --git a/drivers/net/ethernet/marvell/skge.c b/drivers/net/ethernet/marvell/skge.c index 25bf6ec44289..a1bada9eaaf6 100644 --- a/drivers/net/ethernet/marvell/skge.c +++ b/drivers/net/ethernet/marvell/skge.c @@ -3742,10 +3742,7 @@ static int skge_device_event(struct notifier_block *unused, skge = netdev_priv(dev); switch (event) { case NETDEV_CHANGENAME: - if (skge->debugfs) - skge->debugfs = debugfs_rename(skge_debug, - skge->debugfs, - skge_debug, dev->name); + debugfs_change_name(skge->debugfs, "%s", dev->name); break; case NETDEV_GOING_DOWN: diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c index 988fa28cfb5f..d7121c836508 100644 --- a/drivers/net/ethernet/marvell/sky2.c +++ b/drivers/net/ethernet/marvell/sky2.c @@ -4494,10 +4494,7 @@ static int sky2_device_event(struct notifier_block *unused, switch (event) { case NETDEV_CHANGENAME: - if (sky2->debugfs) { - sky2->debugfs = debugfs_rename(sky2_debug, sky2->debugfs, - sky2_debug, dev->name); - } + debugfs_change_name(sky2->debugfs, "%s", dev->name); break; case NETDEV_GOING_DOWN: diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index c81ea8cdfe6e..82e2908016bd 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -6489,11 +6489,7 @@ static int stmmac_device_event(struct notifier_block *unused, switch (event) { case NETDEV_CHANGENAME: - if (priv->dbgfs_dir) - priv->dbgfs_dir = debugfs_rename(stmmac_fs_dir, - priv->dbgfs_dir, - stmmac_fs_dir, - dev->name); + debugfs_change_name(priv->dbgfs_dir, "%s", dev->name); break; } done: diff --git a/drivers/opp/debugfs.c b/drivers/opp/debugfs.c index 105de7c3274a..8fc6238b1728 100644 --- a/drivers/opp/debugfs.c +++ b/drivers/opp/debugfs.c @@ -217,7 +217,7 @@ static void opp_migrate_dentry(struct opp_device *opp_dev, { struct opp_device *new_dev = NULL, *iter; const struct device *dev; - struct dentry *dentry; + int err; /* Look for next opp-dev */ list_for_each_entry(iter, &opp_table->dev_list, node) @@ -234,16 +234,14 @@ static void opp_migrate_dentry(struct opp_device *opp_dev, opp_set_dev_name(dev, opp_table->dentry_name); - dentry = debugfs_rename(rootdir, opp_dev->dentry, rootdir, - opp_table->dentry_name); - if (IS_ERR(dentry)) { + err = debugfs_change_name(opp_dev->dentry, "%s", opp_table->dentry_name); + if (err) { dev_err(dev, "%s: Failed to rename link from: %s to %s\n", __func__, dev_name(opp_dev->dev), dev_name(dev)); return; } - new_dev->dentry = dentry; - opp_table->dentry = dentry; + new_dev->dentry = opp_table->dentry = opp_dev->dentry; } /** diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 51d4c3e9d422..75715d8877ee 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -830,76 +830,70 @@ void debugfs_lookup_and_remove(const char *name, struct dentry *parent) EXPORT_SYMBOL_GPL(debugfs_lookup_and_remove); /** - * debugfs_rename - rename a file/directory in the debugfs filesystem - * @old_dir: a pointer to the parent dentry for the renamed object. This - * should be a directory dentry. - * @old_dentry: dentry of an object to be renamed. - * @new_dir: a pointer to the parent dentry where the object should be - * moved. This should be a directory dentry. - * @new_name: a pointer to a string containing the target name. + * debugfs_change_name - rename a file/directory in the debugfs filesystem + * @dentry: dentry of an object to be renamed. + * @fmt: format for new name * * This function renames a file/directory in debugfs. The target must not * exist for rename to succeed. * - * This function will return a pointer to old_dentry (which is updated to - * reflect renaming) if it succeeds. If an error occurs, ERR_PTR(-ERROR) - * will be returned. + * This function will return 0 on success and -E... on failure. * * If debugfs is not enabled in the kernel, the value -%ENODEV will be * returned. */ -struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, - struct dentry *new_dir, const char *new_name) +int __printf(2, 3) debugfs_change_name(struct dentry *dentry, const char *fmt, ...) { - int error; - struct dentry *dentry = NULL, *trap; + int error = 0; + const char *new_name; struct name_snapshot old_name; + struct dentry *parent, *target; + struct inode *dir; + va_list ap; - if (IS_ERR(old_dir)) - return old_dir; - if (IS_ERR(new_dir)) - return new_dir; - if (IS_ERR_OR_NULL(old_dentry)) - return old_dentry; - - trap = lock_rename(new_dir, old_dir); - /* Source or destination directories don't exist? */ - if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) - goto exit; - /* Source does not exist, cyclic rename, or mountpoint? */ - if (d_really_is_negative(old_dentry) || old_dentry == trap || - d_mountpoint(old_dentry)) - goto exit; - dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); - /* Lookup failed, cyclic rename or target exists? */ - if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) - goto exit; - - take_dentry_name_snapshot(&old_name, old_dentry); - - error = simple_rename(&nop_mnt_idmap, d_inode(old_dir), old_dentry, - d_inode(new_dir), dentry, 0); - if (error) { - release_dentry_name_snapshot(&old_name); - goto exit; + if (IS_ERR_OR_NULL(dentry)) + return 0; + + va_start(ap, fmt); + new_name = kvasprintf_const(GFP_KERNEL, fmt, ap); + va_end(ap); + if (!new_name) + return -ENOMEM; + + parent = dget_parent(dentry); + dir = d_inode(parent); + inode_lock(dir); + + take_dentry_name_snapshot(&old_name, dentry); + + if (WARN_ON_ONCE(dentry->d_parent != parent)) { + error = -EINVAL; + goto out; + } + if (strcmp(old_name.name.name, new_name) == 0) + goto out; + target = lookup_one_len(new_name, parent, strlen(new_name)); + if (IS_ERR(target)) { + error = PTR_ERR(target); + goto out; } - d_move(old_dentry, dentry); - fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name, - d_is_dir(old_dentry), - NULL, old_dentry); + if (d_really_is_positive(target)) { + dput(target); + error = -EINVAL; + goto out; + } + simple_rename_timestamp(dir, dentry, dir, target); + d_move(dentry, target); + dput(target); + fsnotify_move(dir, dir, &old_name.name, d_is_dir(dentry), NULL, dentry); +out: release_dentry_name_snapshot(&old_name); - unlock_rename(new_dir, old_dir); - dput(dentry); - return old_dentry; -exit: - if (dentry && !IS_ERR(dentry)) - dput(dentry); - unlock_rename(new_dir, old_dir); - if (IS_ERR(dentry)) - return dentry; - return ERR_PTR(-EINVAL); + inode_unlock(dir); + dput(parent); + kfree_const(new_name); + return error; } -EXPORT_SYMBOL_GPL(debugfs_rename); +EXPORT_SYMBOL_GPL(debugfs_change_name); /** * debugfs_initialized - Tells whether debugfs has been registered diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index 68e9c6cbd835..fa2568b4380d 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -175,8 +175,7 @@ ssize_t debugfs_attr_write(struct file *file, const char __user *buf, ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf, size_t len, loff_t *ppos); -struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, - struct dentry *new_dir, const char *new_name); +int debugfs_change_name(struct dentry *dentry, const char *fmt, ...) __printf(2, 3); void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent, u8 *value); @@ -361,10 +360,10 @@ static inline ssize_t debugfs_attr_write_signed(struct file *file, return -ENODEV; } -static inline struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, - struct dentry *new_dir, char *new_name) +static inline int __printf(2, 3) debugfs_change_name(struct dentry *dentry, + const char *fmt, ...) { - return ERR_PTR(-ENODEV); + return -ENODEV; } static inline void debugfs_create_u8(const char *name, umode_t mode, diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c index 4a85b94d12ce..794bd433cce0 100644 --- a/mm/shrinker_debug.c +++ b/mm/shrinker_debug.c @@ -195,8 +195,6 @@ int shrinker_debugfs_add(struct shrinker *shrinker) int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...) { - struct dentry *entry; - char buf[128]; const char *new, *old; va_list ap; int ret = 0; @@ -213,18 +211,8 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...) old = shrinker->name; shrinker->name = new; - if (shrinker->debugfs_entry) { - snprintf(buf, sizeof(buf), "%s-%d", shrinker->name, - shrinker->debugfs_id); - - entry = debugfs_rename(shrinker_debugfs_root, - shrinker->debugfs_entry, - shrinker_debugfs_root, buf); - if (IS_ERR(entry)) - ret = PTR_ERR(entry); - else - shrinker->debugfs_entry = entry; - } + ret = debugfs_change_name(shrinker->debugfs_entry, "%s-%d", + shrinker->name, shrinker->debugfs_id); mutex_unlock(&shrinker_mutex); diff --git a/net/hsr/hsr_debugfs.c b/net/hsr/hsr_debugfs.c index 1a195efc79cd..5b2cfac3b2ba 100644 --- a/net/hsr/hsr_debugfs.c +++ b/net/hsr/hsr_debugfs.c @@ -57,14 +57,11 @@ DEFINE_SHOW_ATTRIBUTE(hsr_node_table); void hsr_debugfs_rename(struct net_device *dev) { struct hsr_priv *priv = netdev_priv(dev); - struct dentry *d; + int err; - d = debugfs_rename(hsr_debugfs_root_dir, priv->node_tbl_root, - hsr_debugfs_root_dir, dev->name); - if (IS_ERR(d)) + err = debugfs_change_name(priv->node_tbl_root, "%s", dev->name); + if (err) netdev_warn(dev, "failed to rename\n"); - else - priv->node_tbl_root = d; } /* hsr_debugfs_init - create hsr node_table file for dumping diff --git a/net/mac80211/debugfs_netdev.c b/net/mac80211/debugfs_netdev.c index a9bc2fd59f55..9fa38c489edc 100644 --- a/net/mac80211/debugfs_netdev.c +++ b/net/mac80211/debugfs_netdev.c @@ -1025,16 +1025,7 @@ void ieee80211_debugfs_remove_netdev(struct ieee80211_sub_if_data *sdata) void ieee80211_debugfs_rename_netdev(struct ieee80211_sub_if_data *sdata) { - struct dentry *dir; - char buf[10 + IFNAMSIZ]; - - dir = sdata->vif.debugfs_dir; - - if (IS_ERR_OR_NULL(dir)) - return; - - sprintf(buf, "netdev:%s", sdata->name); - debugfs_rename(dir->d_parent, dir, dir->d_parent, buf); + debugfs_change_name(sdata->vif.debugfs_dir, "netdev:%s", sdata->name); } void ieee80211_debugfs_recreate_netdev(struct ieee80211_sub_if_data *sdata, diff --git a/net/wireless/core.c b/net/wireless/core.c index afbdc549fb4a..9130cb872ed3 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -143,10 +143,7 @@ int cfg80211_dev_rename(struct cfg80211_registered_device *rdev, if (result) return result; - if (!IS_ERR_OR_NULL(rdev->wiphy.debugfsdir)) - debugfs_rename(rdev->wiphy.debugfsdir->d_parent, - rdev->wiphy.debugfsdir, - rdev->wiphy.debugfsdir->d_parent, newname); + debugfs_change_name(rdev->wiphy.debugfsdir, "%s", newname); nl80211_notify_wiphy(rdev, NL80211_CMD_NEW_WIPHY); -- cgit v1.3