limits: 256 PCI functions, 128 sockets and devices, 64 USB interfaces

The fixed tables that a bigger machine than the one they were written
on reaches first, each raised to where it costs little:

  NPCI       64 -> 256   a desktop with cards and Thunderbolt passes 64,
                         and the devices past it -- often the disk or
                         NIC last in bus order -- were ignored; 44 KB
  NSOCK      32 -> 128   Unix sockets, which a desktop session uses by
                         the dozen; 4.9 KB each, 470 KB in all
  NDEVICE    32 -> 128   120 bytes each
  NIFDEV     16 -> 64    one dock is a hub, Ethernet, audio and a card
                         reader at two or three interfaces apiece
  NETIF_MAX   4 -> 8

Device names took one digit and clamped there, so the tenth device of
a kind and every one after it was named "...9". Two digits now.

Checked under QEMU with two bridges of test devices: 68 functions,
all in lspci, /proc/pci and /sys/bus/pci.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4

include/device.h

@@ -67,7 +67,7 @@ struct device {
   int in_use;
 };
 
-#define NDEVICE 32
+#define NDEVICE 128
 
 // Register a device. Returns it, or 0 if the table is full. The name is made
 // unique by appending an index, so a caller passes "vga" and gets "vga0".

include/param.h

@@ -67,5 +67,6 @@
 // Network interfaces the stack will attach. Two is already an ordinary machine
 // -- a laptop with Ethernet plus a virtual adapter -- and each one costs a
 // struct netif, so the limit is about keeping a fixed array honest rather than
-// about memory.
+// about memory. Eight, since a dock's Ethernet and a phone tethered over USB
-#define NETIF_MAX      4
+// sit beside the built-in ones.
+#define NETIF_MAX      8

include/pci.h

@@ -53,7 +53,10 @@
 
 #define PCI_ANY 0xFFFF          // wildcard in a match table
 
-#define NPCI 64                 // devices we will remember
+// Devices we will remember. A laptop has 30 to 60 functions, a desktop with
+// a couple of cards and Thunderbolt more than 64, and every one past the limit
+// was ignored -- including whatever disk or NIC came last in bus order.
+#define NPCI 256
 
 struct pci_bar {
     uint64 base;                // already masked; 0 means "no BAR here"

include/socket.h

@@ -260,7 +260,7 @@ struct rtattr {
 
 #ifdef _KERNEL_SOCKET_INTERNALS
 
-#define NSOCK       32          // sockets in the system
+#define NSOCK      128          // sockets in the system, 4.9 KB each
 #define SOCKBUF     4096        // receive buffer per connected socket
 #define NBACKLOG    8
 

kernel/dev/device.c

@@ -93,11 +93,13 @@ device_add(const char *base, enum dev_bus bus, enum dev_class class,
     d->name[n] = base[n];
     n++;
   }
-  // Single digit is enough for NDEVICE of 32 per base name, and a two-digit
+  // Two digits once there are ten of a kind. This clamped at 9, so the tenth
-  // path that is never taken is a two-digit path that is never tested.
+  // and every later disk or interface of one kind were all called "...9".
+  if (idx > 99)
+    idx = 99;
   if (idx > 9)
-    idx = 9;
+    d->name[n++] = (char)('0' + idx / 10);
-  d->name[n++] = (char)('0' + idx);
+  d->name[n++] = (char)('0' + idx % 10);
   d->name[n]   = '\0';
 
   return d;

kernel/drivers/usb/core/usb.c

@@ -130,9 +130,10 @@ parse_config(struct usb_dev *dev, int nth)
 }
 
 // One usb_dev for every interface after the first. See `base` in
-// include/usb.h. A fixed pool, like everything else here: sixteen is more
+// include/usb.h. A fixed pool, like everything else here. It was sixteen,
-// interfaces than a desk of keyboards, mice and receivers adds up to.
+// which a dock -- hub, Ethernet, audio, card reader, each two or three
-#define NIFDEV 16
+// interfaces -- and a couple of receivers already reach. 672 bytes each.
+#define NIFDEV 64
 static struct usb_dev ifdevs[NIFDEV];
 
 // ---------------------------------------------------------------------------