[PATCH 2/3] serial: Avoid double lookup of serial ports

[Benjamin Herrenschmidt]

The various functions to add a port used to return port->name, and
the callers would immediately iterate all registered ports to "find"
the one just created by comparing that return value with ... port->name.

This is a waste of cycles and code. Instead, have those functions
return "port" directly.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 grub-core/term/arc/serial.c      |  4 ++--
 grub-core/term/ieee1275/serial.c |  6 ++---
 grub-core/term/ns8250-spcr.c     |  2 +-
 grub-core/term/ns8250.c          | 12 +++++-----
 grub-core/term/serial.c          | 41 +++++++++++---------------------
 include/grub/serial.h            | 13 +++++-----
 6 files changed, 33 insertions(+), 45 deletions(-)

diff --git a/grub-core/term/arc/serial.c b/grub-core/term/arc/serial.c
index 87d1ce821..651f814ee 100644
--- a/grub-core/term/arc/serial.c
+++ b/grub-core/term/arc/serial.c
@@ -100,7 +100,7 @@ struct grub_serial_driver grub_arcserial_driver =
     .put = serial_hw_put
   };
 
-const char *
+struct grub_serial_port *
 grub_arcserial_add_port (const char *path)
 {
   struct grub_serial_port *port;
@@ -120,7 +120,7 @@ grub_arcserial_add_port (const char *path)
 
   grub_serial_register (port);
 
-  return port->name;
+  return port;
 }
 
 static int
diff --git a/grub-core/term/ieee1275/serial.c b/grub-core/term/ieee1275/serial.c
index 7df2bee6f..b4aa9d5c5 100644
--- a/grub-core/term/ieee1275/serial.c
+++ b/grub-core/term/ieee1275/serial.c
@@ -217,7 +217,7 @@ dev_iterate (struct grub_ieee1275_devalias *alias)
   return 0;
 }
 
-static const char *
+static struct grub_serial_port *
 add_port (struct ofserial_hash_ent *ent)
 {
   struct grub_serial_port *port;
@@ -245,10 +245,10 @@ add_port (struct ofserial_hash_ent *ent)
 
   grub_serial_register (port);
 
-  return port->name;
+  return port;
 }
 
-const char *
+const struct grub_serial_port *
 grub_ofserial_add_port (const char *path)
 {
   struct ofserial_hash_ent *ent;
diff --git a/grub-core/term/ns8250-spcr.c b/grub-core/term/ns8250-spcr.c
index f4b718833..9fe36733d 100644
--- a/grub-core/term/ns8250-spcr.c
+++ b/grub-core/term/ns8250-spcr.c
@@ -22,7 +22,7 @@
 #include <grub/dl.h>
 #include <grub/acpi.h>
 
-char *
+struct grub_serial_port *
 grub_ns8250_spcr_init (void)
 {
   struct grub_acpi_spcr *spcr;
diff --git a/grub-core/term/ns8250.c b/grub-core/term/ns8250.c
index 98f0b3bc3..1eb6a30b6 100644
--- a/grub-core/term/ns8250.c
+++ b/grub-core/term/ns8250.c
@@ -347,7 +347,7 @@ grub_ns8250_hw_get_port (const unsigned int unit)
     return 0;
 }
 
-char *
+struct grub_serial_port *
 grub_serial_ns8250_add_port (grub_port_t port, struct grub_serial_config 
*config)
 {
   struct grub_serial_port *p;
@@ -361,7 +361,7 @@ grub_serial_ns8250_add_port (grub_port_t port, struct 
grub_serial_config *config
         /* give the opportunity for SPCR to configure a default com port */
         if (config != NULL)
           grub_serial_port_configure (&com_ports[i], config);
-        return com_names[i];
+        return &com_ports[i];
       }
 
   grub_outb (0x5a, port + UART_SR);
@@ -391,10 +391,10 @@ grub_serial_ns8250_add_port (grub_port_t port, struct 
grub_serial_config *config
     grub_serial_config_defaults (p);
   grub_serial_register (p);
 
-  return p->name;
+  return p;
 }
 
-char *
+struct grub_serial_port *
 grub_serial_ns8250_add_mmio (grub_addr_t addr, unsigned int acc_size,
                              struct grub_serial_config *config)
 {
@@ -406,7 +406,7 @@ grub_serial_ns8250_add_mmio (grub_addr_t addr, unsigned int 
acc_size,
       {
         if (config != NULL)
           grub_serial_port_configure (&com_ports[i], config);
-        return com_names[i];
+        return &com_ports[i];
       }
 
   p = grub_malloc (sizeof (*p));
@@ -428,5 +428,5 @@ grub_serial_ns8250_add_mmio (grub_addr_t addr, unsigned int 
acc_size,
     grub_serial_config_defaults (p);
   grub_serial_register (p);
 
-  return p->name;
+  return p;
 }
diff --git a/grub-core/term/serial.c b/grub-core/term/serial.c
index 88bcd4032..275dd61af 100644
--- a/grub-core/term/serial.c
+++ b/grub-core/term/serial.c
@@ -155,14 +155,10 @@ grub_serial_find (const char *name)
   if (!port && grub_strncmp (name, "port", sizeof ("port") - 1) == 0
       && grub_isxdigit (name [sizeof ("port") - 1]))
     {
-      name = grub_serial_ns8250_add_port (grub_strtoul (&name[sizeof ("port") 
- 1],
+      port = grub_serial_ns8250_add_port (grub_strtoul (&name[sizeof ("port") 
- 1],
                                                        0, 16), NULL);
-      if (name == NULL)
+      if (port == NULL)
         return NULL;
-
-      FOR_SERIAL_PORTS (port)
-        if (grub_strcmp (port->name, name) == 0)
-           break;
     }
   if (!port && grub_strncmp (name, "mmio,", sizeof ("mmio,") - 1) == 0
       && grub_isxdigit (name [sizeof ("mmio,") - 1]))
@@ -219,38 +215,29 @@ grub_serial_find (const char *name)
           break;
         }
 
-      name = grub_serial_ns8250_add_mmio (addr, acc_size, NULL);
-      if (name == NULL)
+      port = grub_serial_ns8250_add_mmio (addr, acc_size, NULL);
+      if (port == NULL)
         return NULL;
-
-      FOR_SERIAL_PORTS (port)
-        if (grub_strcmp (port->name, name) == 0) {
-          break;
-        }
     }
   if (!port && grub_strcmp (name, "auto") == 0)
     {
       /* Look for an SPCR if any. If not, default to com0 */
-      name = grub_ns8250_spcr_init ();
-      if (name == NULL)
-        name = "com0";
-
-      FOR_SERIAL_PORTS (port)
-        if (grub_strcmp (port->name, name) == 0)
-          break;
+      port = grub_ns8250_spcr_init ();
+      if (port == NULL)
+        {
+          FOR_SERIAL_PORTS (port)
+            if (grub_strcmp (port->name, "com0") == 0)
+              break;
+       }
     }
 #endif
 
 #ifdef GRUB_MACHINE_IEEE1275
   if (!port && grub_strncmp (name, "ieee1275/", sizeof ("ieee1275/") - 1) == 0)
     {
-      name = grub_ofserial_add_port (&name[sizeof ("ieee1275/") - 1]);
-      if (!name)
-       return NULL;
-
-      FOR_SERIAL_PORTS (port)
-       if (grub_strcmp (port->name, name) == 0)
-         break;
+      port = grub_ofserial_add_port (&name[sizeof ("ieee1275/") - 1]);
+      if (port == NULL)
+        return NULL;
     }
 #endif
 
diff --git a/include/grub/serial.h b/include/grub/serial.h
index 65ccab4ff..17ee0f08b 100644
--- a/include/grub/serial.h
+++ b/include/grub/serial.h
@@ -190,10 +190,12 @@ grub_serial_config_defaults (struct grub_serial_port 
*port)
 
 #if defined(__mips__) || defined (__i386__) || defined (__x86_64__)
 void grub_ns8250_init (void);
-char *grub_ns8250_spcr_init (void);
-char *grub_serial_ns8250_add_port (grub_port_t port, struct grub_serial_config 
*config);
-char *grub_serial_ns8250_add_mmio (grub_addr_t addr, unsigned int acc_size,
-                                   struct grub_serial_config *config);
+struct grub_serial_port *grub_ns8250_spcr_init (void);
+struct grub_serial_port *grub_serial_ns8250_add_port (grub_port_t port,
+                                                     struct grub_serial_config 
*config);
+struct grub_serial_port *grub_serial_ns8250_add_mmio (grub_addr_t addr,
+                                                     unsigned int acc_size,
+                                                     struct grub_serial_config 
*config);
 #endif
 #ifdef GRUB_MACHINE_IEEE1275
 void grub_ofserial_init (void);
@@ -205,8 +207,7 @@ grub_efiserial_init (void);
 #ifdef GRUB_MACHINE_ARC
 void
 grub_arcserial_init (void);
-const char *
-grub_arcserial_add_port (const char *path);
+struct grub_serial_port *grub_arcserial_add_port (const char *path);
 #endif
 
 struct grub_serial_port *grub_serial_find (const char *name);
-- 
2.34.1