usb: usblp: Use min_t() to improve usblp_read()

Use min_t() to improve usblp_read() and avoid calculating
'avail - usblp->readcount' twice. Use min_t(ssize_t,,) instead of min()
to avoid a signedness error.

Signed-off-by: Thorsten Blum <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/class/usblp.c

···
 
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/minmax.h>
 #include <linux/sched/signal.h>
 #include <linux/signal.h>
 #include <linux/poll.h>
···
 		goto done;
 	}
 
-	count = len < avail - usblp->readcount ? len : avail - usblp->readcount;
+	count = min_t(ssize_t, len, avail - usblp->readcount);
 	if (count != 0 &&
 	    copy_to_user(buffer, usblp->readbuf + usblp->readcount, count)) {
 		count = -EFAULT;