Messages in this thread Patch in this message | | | From | Kefeng Wang <> | Subject | [PATCH next 2/3] debugfs: introduce debugfs_create_single[,_data] | Date | Fri, 29 Nov 2019 17:27:51 +0800 |
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Like proc_create_single[,_data] in procfs, introduce a similar debugfs_create_single[,_data] function, which could drastically reduces the boilerplate code.
Rename debugfs_devm_entry to debugfs_entry, and reuse debugfs_entry_ops code. The struct debugfs_entry instance is dynamically allocated and taken as data in debugfs_create_single_data, which need to be freed when calling debugfs_remove, using lowest bit of inode->i_private to distinguish it.
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> --- fs/debugfs/file.c | 58 ++++++++++++++++++++++++++++++++++------- fs/debugfs/inode.c | 4 +++ include/linux/debugfs.h | 18 +++++++++++++ 3 files changed, 70 insertions(+), 10 deletions(-)
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 38c17a99eb17..68f0c4b19bef 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -1106,21 +1106,24 @@ EXPORT_SYMBOL_GPL(debugfs_create_regset32); #endif /* CONFIG_HAS_IOMEM */ -struct debugfs_devm_entry { +struct debugfs_entry { int (*read)(struct seq_file *seq, void *data); - struct device *dev; + void *data; }; -static int debugfs_devm_entry_open(struct inode *inode, struct file *f) +static int debugfs_entry_open(struct inode *inode, struct file *f) { - struct debugfs_devm_entry *entry = inode->i_private; + struct debugfs_entry *entry = inode->i_private; - return single_open(f, entry->read, entry->dev); + if (debugfs_test_lowest_bit(entry)) + entry = debugfs_clear_lowest_bit(entry); + + return single_open(f, entry->read, entry->data); } -static const struct file_operations debugfs_devm_entry_ops = { +static const struct file_operations debugfs_entry_ops = { .owner = THIS_MODULE, - .open = debugfs_devm_entry_open, + .open = debugfs_entry_open, .release = single_release, .read = seq_read, .llseek = seq_lseek @@ -1141,7 +1144,7 @@ struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name, int (*read_fn)(struct seq_file *s, void *data)) { - struct debugfs_devm_entry *entry; + struct debugfs_entry *entry; if (IS_ERR(parent)) return ERR_PTR(-ENOENT); @@ -1151,10 +1154,45 @@ struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name, return ERR_PTR(-ENOMEM); entry->read = read_fn; - entry->dev = dev; + entry->data = dev; return debugfs_create_file(name, S_IRUGO, parent, entry, - &debugfs_devm_entry_ops); + &debugfs_entry_ops); } EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile); +/** + * debugfs_create_single_data - create a file in the debugfs filesystem + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is NULL, then the + * file will be created in the root of the debugfs filesystem. + * @data: a pointer to something that the caller will want to get to later + * on. The inode.i_private pointer will point to this value on + * the open() call. + * @read_fn: function pointer called to print the seq_file content. + * + * This function creates a file in debugfs with the extra data and a seq_file + * show callback. + */ +struct dentry *debugfs_create_single_data(const char *name, umode_t mode, + struct dentry *parent, void *data, + int (*read_fn)(struct seq_file *s, + void *data)) +{ + struct debugfs_entry *entry; + + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return ERR_PTR(-ENOMEM); + + entry->read = read_fn; + entry->data = data; + + entry = debugfs_set_lowest_bit(entry); + + return debugfs_create_file(name, mode, parent, entry, + &debugfs_entry_ops); +} +EXPORT_SYMBOL_GPL(debugfs_create_single_data); diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index cc24e97686d0..58cbb7af2a55 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -197,6 +197,10 @@ static void debugfs_free_inode(struct inode *inode) { if (S_ISLNK(inode->i_mode)) kfree(inode->i_link); + + if (debugfs_test_lowest_bit(inode->i_private)) + kfree(debugfs_clear_lowest_bit(inode->i_private)); + free_inode_nonrcu(inode); } diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index bf9b6cafa4c2..82171f183e93 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -142,6 +142,11 @@ struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name, int (*read_fn)(struct seq_file *s, void *data)); +struct dentry *debugfs_create_single_data(const char *name, umode_t mode, + struct dentry *parent, void *data, + int (*read_fn)(struct seq_file *s, + void *data)); + bool debugfs_initialized(void); ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf, @@ -336,6 +341,16 @@ static inline struct dentry *debugfs_create_devm_seqfile(struct device *dev, return ERR_PTR(-ENODEV); } +static inline struct dentry *debugfs_create_single_data(const char *name, + umode_t mode, + struct dentry *parent, + void *data, + int (*read_fn)(struct seq_file *s, + void *data)) +{ + return ERR_PTR(-ENODEV); +} + static inline ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) @@ -352,6 +367,9 @@ static inline ssize_t debugfs_write_file_bool(struct file *file, #endif +#define debugfs_create_single(name, mode, parent, read) \ + debugfs_create_single_data(name, mode, parent, NULL, read) + /** * debugfs_create_xul - create a debugfs file that is used to read and write an * unsigned long value, formatted in hexadecimal -- 2.20.1
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