minmax: scsi: fix mis-use of 'clamp()' in sr.c

BugLink: https://bugs.launchpad.net/bugs/2083196

commit 9f499b8c791d2983c0a31a543c51d1b2f15e8755 upstream.

While working on simplifying the minmax functions, and avoiding
excessive macro expansion, it turns out that the sr.c use of the
'clamp()' macro has the arguments the wrong way around.

The clamp logic is

	val = clamp(in, low, high);

and it returns the input clamped to the low/high limits. But sr.c ddid

	speed = clamp(0, speed, 0xffff / 177);

which clamps the value '0' to the range '[speed, 0xffff / 177]' and ends
up being nonsensical.

Happily, I don't think anybody ever cared.

Fixes: 9fad9d560af5 ("scsi: sr: Fix unintentional arithmetic wraparound")
Cc: Justin Stitt <justinstitt@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Wentao Guan <guanwentao@uniontech.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Portia Stephens <portia.stephens@canonical.com>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>

drivers/scsi/sr_ioctl.c

@@ -431,7 +431,7 @@ int sr_select_speed(struct cdrom_device_info *cdi, unsigned long speed)
 	struct packet_command cgc;
 
 	/* avoid exceeding the max speed or overflowing integer bounds */
-	speed = clamp(0, speed, 0xffff / 177);
+	speed = clamp(speed, 0, 0xffff / 177);
 
 	if (speed == 0)
 		speed = 0xffff;	/* set to max */