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author | David Woodhouse <David.Woodhouse@intel.com> | 2008-07-11 14:36:25 +0100 |
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committer | David Woodhouse <David.Woodhouse@intel.com> | 2008-07-11 14:36:25 +0100 |
commit | a8931ef380c92d121ae74ecfb03b2d63f72eea6f (patch) | |
tree | 980fb6b019e11e6cb1ece55b7faff184721a8053 /include/linux/fdtable.h | |
parent | [MTD] [NAND] Fix checkpatch warnings which showed up when atmel_nand.c moved (diff) | |
parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 (diff) | |
download | linux-dev-a8931ef380c92d121ae74ecfb03b2d63f72eea6f.tar.xz linux-dev-a8931ef380c92d121ae74ecfb03b2d63f72eea6f.zip |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Diffstat (limited to 'include/linux/fdtable.h')
-rw-r--r-- | include/linux/fdtable.h | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h new file mode 100644 index 000000000000..4aab6f12cfab --- /dev/null +++ b/include/linux/fdtable.h @@ -0,0 +1,100 @@ +/* + * descriptor table internals; you almost certainly want file.h instead. + */ + +#ifndef __LINUX_FDTABLE_H +#define __LINUX_FDTABLE_H + +#include <asm/atomic.h> +#include <linux/posix_types.h> +#include <linux/compiler.h> +#include <linux/spinlock.h> +#include <linux/rcupdate.h> +#include <linux/types.h> + +/* + * The default fd array needs to be at least BITS_PER_LONG, + * as this is the granularity returned by copy_fdset(). + */ +#define NR_OPEN_DEFAULT BITS_PER_LONG + +/* + * The embedded_fd_set is a small fd_set, + * suitable for most tasks (which open <= BITS_PER_LONG files) + */ +struct embedded_fd_set { + unsigned long fds_bits[1]; +}; + +struct fdtable { + unsigned int max_fds; + struct file ** fd; /* current fd array */ + fd_set *close_on_exec; + fd_set *open_fds; + struct rcu_head rcu; + struct fdtable *next; +}; + +/* + * Open file table structure + */ +struct files_struct { + /* + * read mostly part + */ + atomic_t count; + struct fdtable *fdt; + struct fdtable fdtab; + /* + * written part on a separate cache line in SMP + */ + spinlock_t file_lock ____cacheline_aligned_in_smp; + int next_fd; + struct embedded_fd_set close_on_exec_init; + struct embedded_fd_set open_fds_init; + struct file * fd_array[NR_OPEN_DEFAULT]; +}; + +#define files_fdtable(files) (rcu_dereference((files)->fdt)) + +extern struct kmem_cache *filp_cachep; + +struct file_operations; +struct vfsmount; +struct dentry; + +extern int expand_files(struct files_struct *, int nr); +extern void free_fdtable_rcu(struct rcu_head *rcu); +extern void __init files_defer_init(void); + +static inline void free_fdtable(struct fdtable *fdt) +{ + call_rcu(&fdt->rcu, free_fdtable_rcu); +} + +static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd) +{ + struct file * file = NULL; + struct fdtable *fdt = files_fdtable(files); + + if (fd < fdt->max_fds) + file = rcu_dereference(fdt->fd[fd]); + return file; +} + +/* + * Check whether the specified fd has an open file. + */ +#define fcheck(fd) fcheck_files(current->files, fd) + +struct task_struct; + +struct files_struct *get_files_struct(struct task_struct *); +void put_files_struct(struct files_struct *fs); +void reset_files_struct(struct files_struct *); +int unshare_files(struct files_struct **); +struct files_struct *dup_fd(struct files_struct *, int *); + +extern struct kmem_cache *files_cachep; + +#endif /* __LINUX_FDTABLE_H */ |