Messages in this thread Patch in this message | | | From | Tejun Heo <> | Subject | [PATCH 25/34] sysfs, kernfs: add kernfs_ops->seq_{start|next|stop}() | Date | Thu, 24 Oct 2013 11:49:31 -0400 |
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kernfs_ops currently only supports single_open() behavior which is pretty restrictive. Add optional callbacks ->seq_{start|next|stop}() which, when implemented, are invoked for seq_file traversal. This allows full seq_file functionality for kernfs users. This currently doesn't have any user and doesn't change any behavior.
Signed-off-by: Tejun Heo <tj@kernel.org> --- fs/sysfs/file.c | 23 +++++++++++++++++++---- include/linux/kernfs.h | 9 +++++++-- 2 files changed, 26 insertions(+), 6 deletions(-)
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index fa4d63d..89134fc 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -146,6 +146,7 @@ static ssize_t sysfs_kf_bin_read(struct sysfs_open_file *of, char *buf, static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos) { struct sysfs_open_file *of = sf->private; + const struct kernfs_ops *ops; /* * @of->mutex nests outside active ref and is just to ensure that @@ -157,19 +158,33 @@ static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos) return ERR_PTR(-ENODEV); } - /* the same behavior as single_open() */ - return NULL + !*ppos; + ops = kernfs_ops(of->sd); + if (ops->seq_start) + return ops->seq_start(sf, ppos); + else + return NULL + !*ppos; /* the same behavior as single_open() */ } static void *kernfs_seq_next(struct seq_file *sf, void *v, loff_t *ppos) { - ++*ppos; - return NULL; + struct sysfs_open_file *of = sf->private; + const struct kernfs_ops *ops = kernfs_ops(of->sd); + + if (ops->seq_next) { + return ops->seq_next(sf, v, ppos); + } else { + ++*ppos; + return NULL; + } } static void kernfs_seq_stop(struct seq_file *sf, void *v) { struct sysfs_open_file *of = sf->private; + const struct kernfs_ops *ops = kernfs_ops(of->sd); + + if (ops->seq_stop) + ops->seq_stop(sf, v); sysfs_put_active(of->sd); mutex_unlock(&of->mutex); diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index a1b94b7..222040c 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -36,8 +36,9 @@ struct kernfs_ops { /* * Read is handled by either seq_file or raw_read(). * - * If seq_show() is present, seq_file path is active. The behavior - * is equivalent to single_open(). @sf->private points to the + * If seq_show() is present, seq_file path is active. Other seq + * operations are optional and if not implemented, the behavior is + * equivalent to single_open(). @sf->private points to the * associated sysfs_open_file. * * read() is bounced through kernel buffer and a read larger than @@ -45,6 +46,10 @@ struct kernfs_ops { */ int (*seq_show)(struct seq_file *sf, void *v); + void *(*seq_start)(struct seq_file *sf, loff_t *ppos); + void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); + void (*seq_stop)(struct seq_file *sf, void *v); + ssize_t (*read)(struct sysfs_open_file *of, char *buf, size_t bytes, loff_t off); -- 1.8.3.1
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