diff options
| author | Thomas Weißschuh <linux@weissschuh.net> | 2024-11-03 17:03:38 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-11-05 14:00:28 +0100 |
| commit | eb2e6c3a8d66ff37b2ee26cd32334ae0e05fd596 (patch) | |
| tree | 72b99b7824ff5928bb6ea7bc29f7139c4736a1fd /fs/sysfs | |
| parent | ae587a509903cca138e910445d8c21fe73b45c80 (diff) | |
sysfs: bin_attribute: add const read/write callback variants
To make it possible to put struct bin_attribute into read-only memory,
the sysfs core has to stop passing mutable pointers to the read() and
write() callbacks.
As there are numerous implementors of these callbacks throughout the
tree it's not possible to change all of them at once.
To enable a step-by-step transition, add new variants of the read() and
write() callbacks which differ only in the constness of the struct
bin_attribute argument.
As most binary attributes are defined through macros, extend these
macros to transparently handle both variants of callbacks to minimize
the churn during the transition.
As soon as all handlers are switch to the const variant, the non-const
one can be removed together with the transition machinery.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20241103-sysfs-const-bin_attr-v2-9-71110628844c@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/sysfs')
| -rw-r--r-- | fs/sysfs/file.c | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 6d39696b4306..785408861c01 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -91,9 +91,12 @@ static ssize_t sysfs_kf_bin_read(struct kernfs_open_file *of, char *buf, count = size - pos; } - if (!battr->read) + if (!battr->read && !battr->read_new) return -EIO; + if (battr->read_new) + return battr->read_new(of->file, kobj, battr, buf, pos, count); + return battr->read(of->file, kobj, battr, buf, pos, count); } @@ -152,9 +155,12 @@ static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf, if (!count) return 0; - if (!battr->write) + if (!battr->write && !battr->write_new) return -EIO; + if (battr->write_new) + return battr->write_new(of->file, kobj, battr, buf, pos, count); + return battr->write(of->file, kobj, battr, buf, pos, count); } @@ -323,13 +329,19 @@ int sysfs_add_bin_file_mode_ns(struct kernfs_node *parent, const struct kernfs_ops *ops; struct kernfs_node *kn; + if (battr->read && battr->read_new) + return -EINVAL; + + if (battr->write && battr->write_new) + return -EINVAL; + if (battr->mmap) ops = &sysfs_bin_kfops_mmap; - else if (battr->read && battr->write) + else if ((battr->read || battr->read_new) && (battr->write || battr->write_new)) ops = &sysfs_bin_kfops_rw; - else if (battr->read) + else if (battr->read || battr->read_new) ops = &sysfs_bin_kfops_ro; - else if (battr->write) + else if (battr->write || battr->write_new) ops = &sysfs_bin_kfops_wo; else ops = &sysfs_file_kfops_empty; |