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-rw-r--r--fs/sysfs/file.c32
1 files changed, 28 insertions, 4 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 4ad3721a991c..dfe928a9540f 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -102,6 +102,22 @@ static ssize_t sysfs_kf_bin_read(struct kernfs_open_file *of, char *buf,
return battr->read(of->file, kobj, battr, buf, pos, count);
}
+/* kernfs read callback for regular sysfs files with pre-alloc */
+static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf,
+ size_t count, loff_t pos)
+{
+ const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
+ struct kobject *kobj = of->kn->parent->priv;
+
+ /*
+ * If buf != of->prealloc_buf, we don't know how
+ * large it is, so cannot safely pass it to ->show
+ */
+ if (pos || WARN_ON_ONCE(buf != of->prealloc_buf))
+ return 0;
+ return ops->show(kobj, of->kn->priv, buf);
+}
+
/* kernfs write callback for regular sysfs files */
static ssize_t sysfs_kf_write(struct kernfs_open_file *of, char *buf,
size_t count, loff_t pos)
@@ -184,13 +200,18 @@ static const struct kernfs_ops sysfs_file_kfops_rw = {
.write = sysfs_kf_write,
};
+static const struct kernfs_ops sysfs_prealloc_kfops_ro = {
+ .read = sysfs_kf_read,
+ .prealloc = true,
+};
+
static const struct kernfs_ops sysfs_prealloc_kfops_wo = {
.write = sysfs_kf_write,
.prealloc = true,
};
static const struct kernfs_ops sysfs_prealloc_kfops_rw = {
- .seq_show = sysfs_kf_seq_show,
+ .read = sysfs_kf_read,
.write = sysfs_kf_write,
.prealloc = true,
};
@@ -238,9 +259,12 @@ int sysfs_add_file_mode_ns(struct kernfs_node *parent,
ops = &sysfs_prealloc_kfops_rw;
else
ops = &sysfs_file_kfops_rw;
- } else if (sysfs_ops->show)
- ops = &sysfs_file_kfops_ro;
- else if (sysfs_ops->store) {
+ } else if (sysfs_ops->show) {
+ if (mode & SYSFS_PREALLOC)
+ ops = &sysfs_prealloc_kfops_ro;
+ else
+ ops = &sysfs_file_kfops_ro;
+ } else if (sysfs_ops->store) {
if (mode & SYSFS_PREALLOC)
ops = &sysfs_prealloc_kfops_wo;
else