From badf16621c1f9d1ac753be056fce11b43d6e0be5 Mon Sep 17 00:00:00 2001 From: Dipankar Sarma Date: Fri, 9 Sep 2005 13:04:10 -0700 Subject: [PATCH] files: break up files struct In order for the RCU to work, the file table array, sets and their sizes must be updated atomically. Instead of ensuring this through too many memory barriers, we put the arrays and their sizes in a separate structure. This patch takes the first step of putting the file table elements in a separate structure fdtable that is embedded withing files_struct. It also changes all the users to refer to the file table using files_fdtable() macro. Subsequent applciation of RCU becomes easier after this. Signed-off-by: Dipankar Sarma Signed-Off-By: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'kernel/exit.c') diff --git a/kernel/exit.c b/kernel/exit.c index 5b0fb9f..83beb1e 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -368,17 +368,19 @@ EXPORT_SYMBOL(daemonize); static inline void close_files(struct files_struct * files) { int i, j; + struct fdtable *fdt; j = 0; + fdt = files_fdtable(files); for (;;) { unsigned long set; i = j * __NFDBITS; - if (i >= files->max_fdset || i >= files->max_fds) + if (i >= fdt->max_fdset || i >= fdt->max_fds) break; - set = files->open_fds->fds_bits[j++]; + set = fdt->open_fds->fds_bits[j++]; while (set) { if (set & 1) { - struct file * file = xchg(&files->fd[i], NULL); + struct file * file = xchg(&fdt->fd[i], NULL); if (file) filp_close(file, files); } @@ -403,16 +405,19 @@ struct files_struct *get_files_struct(struct task_struct *task) void fastcall put_files_struct(struct files_struct *files) { + struct fdtable *fdt; + if (atomic_dec_and_test(&files->count)) { close_files(files); /* * Free the fd and fdset arrays if we expanded them. */ - if (files->fd != &files->fd_array[0]) - free_fd_array(files->fd, files->max_fds); - if (files->max_fdset > __FD_SETSIZE) { - free_fdset(files->open_fds, files->max_fdset); - free_fdset(files->close_on_exec, files->max_fdset); + fdt = files_fdtable(files); + if (fdt->fd != &files->fd_array[0]) + free_fd_array(fdt->fd, fdt->max_fds); + if (fdt->max_fdset > __FD_SETSIZE) { + free_fdset(fdt->open_fds, fdt->max_fdset); + free_fdset(fdt->close_on_exec, fdt->max_fdset); } kmem_cache_free(files_cachep, files); } -- cgit v1.1