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Diffstat (limited to 'fs/file_table.c')
-rw-r--r--fs/file_table.c40
1 files changed, 29 insertions, 11 deletions
diff --git a/fs/file_table.c b/fs/file_table.c
index 43e9e1737de..86ec8ae985b 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -14,6 +14,7 @@
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/eventpoll.h>
+#include <linux/rcupdate.h>
#include <linux/mount.h>
#include <linux/cdev.h>
#include <linux/fsnotify.h>
@@ -53,11 +54,17 @@ void filp_dtor(void * objp, struct kmem_cache_s *cachep, unsigned long dflags)
spin_unlock_irqrestore(&filp_count_lock, flags);
}
-static inline void file_free(struct file *f)
+static inline void file_free_rcu(struct rcu_head *head)
{
+ struct file *f = container_of(head, struct file, f_rcuhead);
kmem_cache_free(filp_cachep, f);
}
+static inline void file_free(struct file *f)
+{
+ call_rcu(&f->f_rcuhead, file_free_rcu);
+}
+
/* Find an unused file structure and return a pointer to it.
* Returns NULL, if there are no more free file structures or
* we run out of memory.
@@ -110,7 +117,7 @@ EXPORT_SYMBOL(get_empty_filp);
void fastcall fput(struct file *file)
{
- if (atomic_dec_and_test(&file->f_count))
+ if (rcuref_dec_and_test(&file->f_count))
__fput(file);
}
@@ -156,11 +163,17 @@ struct file fastcall *fget(unsigned int fd)
struct file *file;
struct files_struct *files = current->files;
- spin_lock(&files->file_lock);
+ rcu_read_lock();
file = fcheck_files(files, fd);
- if (file)
- get_file(file);
- spin_unlock(&files->file_lock);
+ if (file) {
+ if (!rcuref_inc_lf(&file->f_count)) {
+ /* File object ref couldn't be taken */
+ rcu_read_unlock();
+ return NULL;
+ }
+ }
+ rcu_read_unlock();
+
return file;
}
@@ -182,21 +195,25 @@ struct file fastcall *fget_light(unsigned int fd, int *fput_needed)
if (likely((atomic_read(&files->count) == 1))) {
file = fcheck_files(files, fd);
} else {
- spin_lock(&files->file_lock);
+ rcu_read_lock();
file = fcheck_files(files, fd);
if (file) {
- get_file(file);
- *fput_needed = 1;
+ if (rcuref_inc_lf(&file->f_count))
+ *fput_needed = 1;
+ else
+ /* Didn't get the reference, someone's freed */
+ file = NULL;
}
- spin_unlock(&files->file_lock);
+ rcu_read_unlock();
}
+
return file;
}
void put_filp(struct file *file)
{
- if (atomic_dec_and_test(&file->f_count)) {
+ if (rcuref_dec_and_test(&file->f_count)) {
security_file_free(file);
file_kill(file);
file_free(file);
@@ -257,4 +274,5 @@ void __init files_init(unsigned long mempages)
files_stat.max_files = n;
if (files_stat.max_files < NR_FILE)
files_stat.max_files = NR_FILE;
+ files_defer_init();
}