2647537197
A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200720155530.1173732-19-a.darwish@linutronix.de
46 lines
1 KiB
C
46 lines
1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_FS_STRUCT_H
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#define _LINUX_FS_STRUCT_H
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#include <linux/path.h>
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#include <linux/spinlock.h>
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#include <linux/seqlock.h>
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struct fs_struct {
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int users;
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spinlock_t lock;
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seqcount_spinlock_t seq;
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int umask;
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int in_exec;
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struct path root, pwd;
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} __randomize_layout;
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extern struct kmem_cache *fs_cachep;
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extern void exit_fs(struct task_struct *);
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extern void set_fs_root(struct fs_struct *, const struct path *);
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extern void set_fs_pwd(struct fs_struct *, const struct path *);
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extern struct fs_struct *copy_fs_struct(struct fs_struct *);
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extern void free_fs_struct(struct fs_struct *);
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extern int unshare_fs_struct(void);
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static inline void get_fs_root(struct fs_struct *fs, struct path *root)
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{
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spin_lock(&fs->lock);
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*root = fs->root;
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path_get(root);
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spin_unlock(&fs->lock);
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}
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static inline void get_fs_pwd(struct fs_struct *fs, struct path *pwd)
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{
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spin_lock(&fs->lock);
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*pwd = fs->pwd;
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path_get(pwd);
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spin_unlock(&fs->lock);
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}
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extern bool current_chrooted(void);
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#endif /* _LINUX_FS_STRUCT_H */
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