Replace the fd_sets in struct fdtable with an array of unsigned longs
Replace the fd_sets in struct fdtable with an array of unsigned longs and then
use the standard non-atomic bit operations rather than the FD_* macros.
This:
(1) Removes the abuses of struct fd_set:
(a) Since we don't want to allocate a full fd_set the vast majority of the
time, we actually, in effect, just allocate a just-big-enough array of
unsigned longs and cast it to an fd_set type - so why bother with the
fd_set at all?
(b) Some places outside of the core fdtable handling code (such as
SELinux) want to look inside the array of unsigned longs hidden inside
the fd_set struct for more efficient iteration over the entire set.
(2) Eliminates the use of FD_*() macros in the kernel completely.
(3) Permits the __FD_*() macros to be deleted entirely where not exposed to
userspace.
Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174954.23314.48147.stgit@warthog.procyon.org.uk
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/exec.c b/fs/exec.c
index 22cc38d..cfd5e30 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1026,10 +1026,10 @@
fdt = files_fdtable(files);
if (i >= fdt->max_fds)
break;
- set = fdt->close_on_exec->fds_bits[j];
+ set = fdt->close_on_exec[j];
if (!set)
continue;
- fdt->close_on_exec->fds_bits[j] = 0;
+ fdt->close_on_exec[j] = 0;
spin_unlock(&files->file_lock);
for ( ; set ; i++,set >>= 1) {
if (set & 1) {
