tty: serial: extract uart_change_port() from uart_set_info()

This "change_port" part of uart_set_info() is for no good reason
inlined there. It makes the function rather hard to read. Therefore,
extract it to a separate function.

This allows for flattening the ifs (with short path "return"s) and
avoiding two levels of indentation. Both making the code really flat and
comprehesible.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20241211074933.92973-4-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index ce3cf95fc9109b21c10236c4abc42d0467495980..c472594c3a9f4215294c5b93546488f545f89004 100644 (file)
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -834,6 +834,61 @@ static int uart_get_info_user(struct tty_struct *tty,
        return uart_get_info(port, ss) < 0 ? -EIO : 0;
 }
 
+static int uart_change_port(struct uart_port *uport,
+                           const struct serial_struct *new_info,
+                           unsigned long new_port)
+{
+       unsigned long old_iobase, old_mapbase;
+       unsigned int old_type, old_iotype, old_hub6, old_shift;
+       int retval;
+
+       old_iobase = uport->iobase;
+       old_mapbase = uport->mapbase;
+       old_type = uport->type;
+       old_hub6 = uport->hub6;
+       old_iotype = uport->iotype;
+       old_shift = uport->regshift;
+
+       if (old_type != PORT_UNKNOWN && uport->ops->release_port)
+               uport->ops->release_port(uport);
+
+       uport->iobase = new_port;
+       uport->type = new_info->type;
+       uport->hub6 = new_info->hub6;
+       uport->iotype = new_info->io_type;
+       uport->regshift = new_info->iomem_reg_shift;
+       uport->mapbase = (unsigned long)new_info->iomem_base;
+
+       if (uport->type == PORT_UNKNOWN || !uport->ops->request_port)
+               return 0;
+
+       retval = uport->ops->request_port(uport);
+       if (retval == 0)
+               return 0; /* succeeded => done */
+
+       /*
+        * If we fail to request resources for the new port, try to restore the
+        * old settings.
+        */
+       uport->iobase = old_iobase;
+       uport->type = old_type;
+       uport->hub6 = old_hub6;
+       uport->iotype = old_iotype;
+       uport->regshift = old_shift;
+       uport->mapbase = old_mapbase;
+
+       if (old_type == PORT_UNKNOWN)
+               return retval;
+
+       retval = uport->ops->request_port(uport);
+       /* If we failed to restore the old settings, we fail like this. */
+       if (retval)
+               uport->type = PORT_UNKNOWN;
+
+       /* We failed anyway. */
+       return -EBUSY;
+}
+
 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
                         struct uart_state *state,
                         struct serial_struct *new_info)
@@ -930,62 +985,9 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
        }
 
        if (change_port) {
-               unsigned long old_iobase, old_mapbase;
-               unsigned int old_type, old_iotype, old_hub6, old_shift;
-
-               old_iobase = uport->iobase;
-               old_mapbase = uport->mapbase;
-               old_type = uport->type;
-               old_hub6 = uport->hub6;
-               old_iotype = uport->iotype;
-               old_shift = uport->regshift;
-
-               /*
-                * Free and release old regions
-                */
-               if (old_type != PORT_UNKNOWN && uport->ops->release_port)
-                       uport->ops->release_port(uport);
-
-               uport->iobase = new_port;
-               uport->type = new_info->type;
-               uport->hub6 = new_info->hub6;
-               uport->iotype = new_info->io_type;
-               uport->regshift = new_info->iomem_reg_shift;
-               uport->mapbase = (unsigned long)new_info->iomem_base;
-
-               /*
-                * Claim and map the new regions
-                */
-               if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
-                       retval = uport->ops->request_port(uport);
-                       /*
-                        * If we fail to request resources for the
-                        * new port, try to restore the old settings.
-                        */
-                       if (retval) {
-                               uport->iobase = old_iobase;
-                               uport->type = old_type;
-                               uport->hub6 = old_hub6;
-                               uport->iotype = old_iotype;
-                               uport->regshift = old_shift;
-                               uport->mapbase = old_mapbase;
-
-                               if (old_type != PORT_UNKNOWN) {
-                                       retval = uport->ops->request_port(uport);
-                                       /*
-                                        * If we failed to restore the old
-                                        * settings, we fail like this.
-                                        */
-                                       if (retval)
-                                               uport->type = PORT_UNKNOWN;
-
-                                       /* We failed anyway. */
-                                       return -EBUSY;
-                               }
-
-                               return retval;
-                       }
-               }
+               retval = uart_change_port(uport, new_info, new_port);
+               if (retval)
+                       return retval;
        }
 
        if (change_irq)