summaryrefslogtreecommitdiffstats
path: root/fs/fcntl.c
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-08-07 13:17:52 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-08-07 13:17:52 +0000
commit3afb00d3f86d3d924f88b56fa8285d4e9db85852 (patch)
tree95a985d3019522cea546b7d8df621369bc44fc6c /fs/fcntl.c
parentAdding debian version 6.9.12-1. (diff)
downloadlinux-3afb00d3f86d3d924f88b56fa8285d4e9db85852.tar.xz
linux-3afb00d3f86d3d924f88b56fa8285d4e9db85852.zip
Merging upstream version 6.10.3.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/fcntl.c')
-rw-r--r--fs/fcntl.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 54cc85d333..300e5d9ad9 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -327,6 +327,22 @@ static long fcntl_set_rw_hint(struct file *file, unsigned int cmd,
return 0;
}
+/* Is the file descriptor a dup of the file? */
+static long f_dupfd_query(int fd, struct file *filp)
+{
+ CLASS(fd_raw, f)(fd);
+
+ /*
+ * We can do the 'fdput()' immediately, as the only thing that
+ * matters is the pointer value which isn't changed by the fdput.
+ *
+ * Technically we didn't need a ref at all, and 'fdget()' was
+ * overkill, but given our lockless file pointer lookup, the
+ * alternatives are complicated.
+ */
+ return f.file == filp;
+}
+
static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
struct file *filp)
{
@@ -342,6 +358,9 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
case F_DUPFD_CLOEXEC:
err = f_dupfd(argi, filp, O_CLOEXEC);
break;
+ case F_DUPFD_QUERY:
+ err = f_dupfd_query(argi, filp);
+ break;
case F_GETFD:
err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
break;
@@ -446,6 +465,7 @@ static int check_fcntl_cmd(unsigned cmd)
switch (cmd) {
case F_DUPFD:
case F_DUPFD_CLOEXEC:
+ case F_DUPFD_QUERY:
case F_GETFD:
case F_SETFD:
case F_GETFL: