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author | Tejun Heo <tj@kernel.org> | 2013-11-28 14:54:21 -0500 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-11-29 17:35:05 -0800 |
commit | f6acf8bb6a40ba3bfcf542e4c4c9e8968c8cb57a (patch) | |
tree | 63a9a946dd065f636a20a9435e2e502313bef178 /include/linux/kernfs.h | |
parent | dd8a5b036b6e8d50854e130555f90f062c5eacec (diff) | |
download | linux-stable-f6acf8bb6a40ba3bfcf542e4c4c9e8968c8cb57a.tar.gz linux-stable-f6acf8bb6a40ba3bfcf542e4c4c9e8968c8cb57a.tar.bz2 linux-stable-f6acf8bb6a40ba3bfcf542e4c4c9e8968c8cb57a.zip |
sysfs, kernfs: introduce kernfs_ops
We're in the process of separating out core sysfs functionality into
kernfs which will deal with sysfs_dirents directly. This patch
introduces kernfs_ops which hosts methods kernfs users implement and
updates fs/sysfs/file.c such that sysfs_kf_*() functions populate
kernfs_ops and kernfs_file_*() functions call the matching entries
from kernfs_ops.
kernfs_ops contains the following groups of methods.
* seq_show() - for kernfs files which use seq_file for reads.
* read() - for direct read implementations. Used iff seq_show() is
not implemented.
* write() - for writes.
* mmap() - for mmaps.
Notes:
* sysfs_elem_attr->ops is added so that kernfs_ops can be accessed
from sysfs_dirent. kernfs_ops() helper is added to verify locking
and access the field.
* SYSFS_FLAG_HAS_(SEQ_SHOW|MMAP) added. sd->s_attr->ops is accessible
only while holding active_ref and there are cases where we want to
take different actions depending on which ops are implemented.
These two flags cache whether the two ops are implemented for those.
* kernfs_file_*() no longer test sysfs type but chooses different
behaviors depending on which methods in kernfs_ops are implemented.
The conversions are trivial except for the open path. As
kernfs_file_open() now decides whether to allow read/write accesses
depending on the kernfs_ops implemented, the presence of methods in
kobjs and attribute_bin should be propagated to kernfs_ops.
sysfs_add_file_mode_ns() is updated so that it propagates presence /
absence of the callbacks through _empty, _ro, _wo, _rw kernfs_ops.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/kernfs.h')
-rw-r--r-- | include/linux/kernfs.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index b923052c29d0..97c6c0f91325 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -33,6 +33,32 @@ struct sysfs_open_file { const struct vm_operations_struct *vm_ops; }; +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 + * associated sysfs_open_file. + * + * read() is bounced through kernel buffer and a read larger than + * PAGE_SIZE results in partial operation of PAGE_SIZE. + */ + int (*seq_show)(struct seq_file *sf, void *v); + + ssize_t (*read)(struct sysfs_open_file *of, char *buf, size_t bytes, + loff_t off); + + /* + * write() is bounced through kernel buffer and a write larger than + * PAGE_SIZE results in partial operation of PAGE_SIZE. + */ + ssize_t (*write)(struct sysfs_open_file *of, char *buf, size_t bytes, + loff_t off); + + int (*mmap)(struct sysfs_open_file *of, struct vm_area_struct *vma); +}; + #ifdef CONFIG_SYSFS struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent, |