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-rw-r--r--fs/kernfs/file.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index dbf397bfdff2..8034706a7af8 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -252,10 +252,18 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
struct kernfs_open_file *of = kernfs_of(file);
- ssize_t len = min_t(size_t, count, PAGE_SIZE);
const struct kernfs_ops *ops;
+ size_t len;
char *buf;
+ if (of->atomic_write_len) {
+ len = count;
+ if (len > of->atomic_write_len)
+ return -E2BIG;
+ } else {
+ len = min_t(size_t, count, PAGE_SIZE);
+ }
+
buf = kmalloc(len + 1, GFP_KERNEL);
if (!buf)
return -ENOMEM;
@@ -653,6 +661,12 @@ static int kernfs_fop_open(struct inode *inode, struct file *file)
of->file = file;
/*
+ * Write path needs to atomic_write_len outside active reference.
+ * Cache it in open_file. See kernfs_fop_write() for details.
+ */
+ of->atomic_write_len = ops->atomic_write_len;
+
+ /*
* Always instantiate seq_file even if read access doesn't use
* seq_file or is not requested. This unifies private data access
* and readable regular files are the vast majority anyway.
@@ -820,7 +834,6 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
bool name_is_static,
struct lock_class_key *key)
{
- struct kernfs_addrm_cxt acxt;
struct kernfs_node *kn;
unsigned flags;
int rc;
@@ -855,10 +868,7 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
if (ops->mmap)
kn->flags |= KERNFS_HAS_MMAP;
- kernfs_addrm_start(&acxt);
- rc = kernfs_add_one(&acxt, kn);
- kernfs_addrm_finish(&acxt);
-
+ rc = kernfs_add_one(kn);
if (rc) {
kernfs_put(kn);
return ERR_PTR(rc);