diff options
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index ecc694debb50..8149f3602881 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -35,6 +35,7 @@ #include <linux/syscalls.h> #include <linux/jiffies.h> #include <linux/futex.h> +#include <linux/rcupdate.h> #include <linux/ptrace.h> #include <linux/mount.h> #include <linux/audit.h> @@ -565,13 +566,12 @@ static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk) return 0; } -static int count_open_files(struct files_struct *files, int size) +static int count_open_files(struct fdtable *fdt) { + int size = fdt->max_fdset; int i; - struct fdtable *fdt; /* Find the last open fd */ - fdt = files_fdtable(files); for (i = size/(8*sizeof(long)); i > 0; ) { if (fdt->open_fds->fds_bits[--i]) break; @@ -592,13 +592,17 @@ static struct files_struct *alloc_files(void) atomic_set(&newf->count, 1); spin_lock_init(&newf->file_lock); - fdt = files_fdtable(newf); + fdt = &newf->fdtab; fdt->next_fd = 0; fdt->max_fds = NR_OPEN_DEFAULT; fdt->max_fdset = __FD_SETSIZE; fdt->close_on_exec = &newf->close_on_exec_init; fdt->open_fds = &newf->open_fds_init; fdt->fd = &newf->fd_array[0]; + INIT_RCU_HEAD(&fdt->rcu); + fdt->free_files = NULL; + fdt->next = NULL; + rcu_assign_pointer(newf->fdt, fdt); out: return newf; } @@ -637,7 +641,7 @@ static int copy_files(unsigned long clone_flags, struct task_struct * tsk) old_fdt = files_fdtable(oldf); new_fdt = files_fdtable(newf); size = old_fdt->max_fdset; - open_files = count_open_files(oldf, old_fdt->max_fdset); + open_files = count_open_files(old_fdt); expand = 0; /* @@ -661,7 +665,14 @@ static int copy_files(unsigned long clone_flags, struct task_struct * tsk) spin_unlock(&newf->file_lock); if (error < 0) goto out_release; + new_fdt = files_fdtable(newf); + /* + * Reacquire the oldf lock and a pointer to its fd table + * who knows it may have a new bigger fd table. We need + * the latest pointer. + */ spin_lock(&oldf->file_lock); + old_fdt = files_fdtable(oldf); } old_fds = old_fdt->fd; @@ -683,7 +694,7 @@ static int copy_files(unsigned long clone_flags, struct task_struct * tsk) */ FD_CLR(open_files - i, new_fdt->open_fds); } - *new_fds++ = f; + rcu_assign_pointer(*new_fds++, f); } spin_unlock(&oldf->file_lock); |