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-rw-r--r--fs/sysfs/file.c59
1 files changed, 50 insertions, 9 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index e9ef59b3abb1..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)
@@ -125,7 +141,7 @@ static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf,
if (size) {
if (size <= pos)
- return 0;
+ return -EFBIG;
count = min_t(ssize_t, count, size - pos);
}
if (!count)
@@ -184,6 +200,22 @@ 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 = {
+ .read = sysfs_kf_read,
+ .write = sysfs_kf_write,
+ .prealloc = true,
+};
+
static const struct kernfs_ops sysfs_bin_kfops_ro = {
.read = sysfs_kf_bin_read,
};
@@ -222,13 +254,22 @@ int sysfs_add_file_mode_ns(struct kernfs_node *parent,
kobject_name(kobj)))
return -EINVAL;
- if (sysfs_ops->show && sysfs_ops->store)
- ops = &sysfs_file_kfops_rw;
- else if (sysfs_ops->show)
- ops = &sysfs_file_kfops_ro;
- else if (sysfs_ops->store)
- ops = &sysfs_file_kfops_wo;
- else
+ if (sysfs_ops->show && sysfs_ops->store) {
+ if (mode & SYSFS_PREALLOC)
+ ops = &sysfs_prealloc_kfops_rw;
+ else
+ ops = &sysfs_file_kfops_rw;
+ } 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
+ ops = &sysfs_file_kfops_wo;
+ } else
ops = &sysfs_file_kfops_empty;
size = PAGE_SIZE;
@@ -253,7 +294,7 @@ int sysfs_add_file_mode_ns(struct kernfs_node *parent,
if (!attr->ignore_lockdep)
key = attr->key ?: (struct lock_class_key *)&attr->skey;
#endif
- kn = __kernfs_create_file(parent, attr->name, mode, size, ops,
+ kn = __kernfs_create_file(parent, attr->name, mode & 0777, size, ops,
(void *)attr, ns, true, key);
if (IS_ERR(kn)) {
if (PTR_ERR(kn) == -EEXIST)