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authorDipankar Sarma <dipankar@in.ibm.com>2005-09-09 13:04:10 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-09 13:57:55 -0700
commitbadf16621c1f9d1ac753be056fce11b43d6e0be5 (patch)
tree3fdf833fdf2e3d3a439090743539680449ec3428 /fs/fcntl.c
parentc0dfb2905126e9e94edebbce8d3e05001301f52d (diff)
downloadlinux-linaro-badf16621c1f9d1ac753be056fce11b43d6e0be5.tar.gz
[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 <dipankar@in.ibm.com> Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/fcntl.c')
-rw-r--r--fs/fcntl.c47
1 files changed, 29 insertions, 18 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 6fbc9d8fcc3..bfecc623808 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -24,20 +24,24 @@
void fastcall set_close_on_exec(unsigned int fd, int flag)
{
struct files_struct *files = current->files;
+ struct fdtable *fdt;
spin_lock(&files->file_lock);
+ fdt = files_fdtable(files);
if (flag)
- FD_SET(fd, files->close_on_exec);
+ FD_SET(fd, fdt->close_on_exec);
else
- FD_CLR(fd, files->close_on_exec);
+ FD_CLR(fd, fdt->close_on_exec);
spin_unlock(&files->file_lock);
}
static inline int get_close_on_exec(unsigned int fd)
{
struct files_struct *files = current->files;
+ struct fdtable *fdt;
int res;
spin_lock(&files->file_lock);
- res = FD_ISSET(fd, files->close_on_exec);
+ fdt = files_fdtable(files);
+ res = FD_ISSET(fd, fdt->close_on_exec);
spin_unlock(&files->file_lock);
return res;
}
@@ -54,24 +58,26 @@ static int locate_fd(struct files_struct *files,
unsigned int newfd;
unsigned int start;
int error;
+ struct fdtable *fdt;
error = -EINVAL;
if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
goto out;
+ fdt = files_fdtable(files);
repeat:
/*
* Someone might have closed fd's in the range
- * orig_start..files->next_fd
+ * orig_start..fdt->next_fd
*/
start = orig_start;
- if (start < files->next_fd)
- start = files->next_fd;
+ if (start < fdt->next_fd)
+ start = fdt->next_fd;
newfd = start;
- if (start < files->max_fdset) {
- newfd = find_next_zero_bit(files->open_fds->fds_bits,
- files->max_fdset, start);
+ if (start < fdt->max_fdset) {
+ newfd = find_next_zero_bit(fdt->open_fds->fds_bits,
+ fdt->max_fdset, start);
}
error = -EMFILE;
@@ -89,8 +95,8 @@ repeat:
if (error)
goto repeat;
- if (start <= files->next_fd)
- files->next_fd = newfd + 1;
+ if (start <= fdt->next_fd)
+ fdt->next_fd = newfd + 1;
error = newfd;
@@ -101,13 +107,16 @@ out:
static int dupfd(struct file *file, unsigned int start)
{
struct files_struct * files = current->files;
+ struct fdtable *fdt;
int fd;
spin_lock(&files->file_lock);
fd = locate_fd(files, file, start);
if (fd >= 0) {
- FD_SET(fd, files->open_fds);
- FD_CLR(fd, files->close_on_exec);
+ /* locate_fd() may have expanded fdtable, load the ptr */
+ fdt = files_fdtable(files);
+ FD_SET(fd, fdt->open_fds);
+ FD_CLR(fd, fdt->close_on_exec);
spin_unlock(&files->file_lock);
fd_install(fd, file);
} else {
@@ -123,6 +132,7 @@ asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
int err = -EBADF;
struct file * file, *tofree;
struct files_struct * files = current->files;
+ struct fdtable *fdt;
spin_lock(&files->file_lock);
if (!(file = fcheck(oldfd)))
@@ -148,13 +158,14 @@ asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
/* Yes. It's a race. In user space. Nothing sane to do */
err = -EBUSY;
- tofree = files->fd[newfd];
- if (!tofree && FD_ISSET(newfd, files->open_fds))
+ fdt = files_fdtable(files);
+ tofree = fdt->fd[newfd];
+ if (!tofree && FD_ISSET(newfd, fdt->open_fds))
goto out_fput;
- files->fd[newfd] = file;
- FD_SET(newfd, files->open_fds);
- FD_CLR(newfd, files->close_on_exec);
+ fdt->fd[newfd] = file;
+ FD_SET(newfd, fdt->open_fds);
+ FD_CLR(newfd, fdt->close_on_exec);
spin_unlock(&files->file_lock);
if (tofree)