Hello list. :)
I rewrote the dev_alloc_name() function in the 2.2.14 Linux kernel's
net/core/dev.c module. It had an apparently artificial limitation on
number of network devices of the same type allowed (100), and was not
implemented in a very efficient manner (which would not be a big deal
under normal circumstances, as this routine wouldn't be called very
often). Just another drop in the bucket. :)
This patch has been through a few iterations, and I've been running on
it for almost a month now (i.e. I consider it stable). I've received
excellent feedback from Ben Canning <[EMAIL PROTECTED]>, and look forward to
more from the great programmers and engineers who are sure to be
perusing this list (rip it up ladies and gentlemen).
--
Daniel Rall <[EMAIL PROTECTED]>
PATCH follows:
--- net/core/dev.c-ORIG Mon Apr 17 02:50:31 2000
+++ net/core/dev.c Sun Apr 30 13:21:06 2000
@@ -17,8 +17,12 @@
* David Hinds <[EMAIL PROTECTED]>
* Alexey Kuznetsov <[EMAIL PROTECTED]>
* Adam Sulmicki <[EMAIL PROTECTED]>
+ * Daniel Rall <[EMAIL PROTECTED]>
*
* Changes:
+ * Daniel Rall : Support an unlimitted number of
devices
+ * of the same type and improve
the
+ * efficiency of device name
allocation.
* Marcelo Tosatti <[EMAIL PROTECTED]> : dont accept mtu 0 or <
* Alan Cox : device private ioctl copies fields back.
* Alan Cox : Transmit queue code does relevant stunts to
@@ -66,6 +70,7 @@
#include <asm/bitops.h>
#include <linux/config.h>
#include <linux/types.h>
+#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
@@ -295,23 +300,60 @@
}
/*
- * Passed a format string - eg "lt%d" it will try and find a suitable
- * id. Not efficient for many devices, not called a lot..
+ * Passed a format string - eg "lt%d" or "eth%d", locates and returns
an
+ * unused id. Assumes the provided device and name have been allocated
+ * properly. Note that a device name is the concatenation of its
type
+ * and id.
*/
-int dev_alloc_name(struct device *dev, const char *name)
+int dev_alloc_name(struct device *device, const char *name_fmt)
{
- int i;
- /*
- * If you need over 100 please also fix the algorithm...
- */
- for(i=0;i<100;i++)
+ char *ptr = strrchr(name_fmt, '%');
+
+ if (ptr != NULL)
{
- sprintf(dev->name,name,i);
- if(dev_get(dev->name)==NULL)
- return i;
+ int id = 0;
+ size_t type_len = (size_t)(ptr - name_fmt);
+
+ register struct device *dev;
+ int n;
+
+ /*
+ * Find the device matching the desired device
+ * name in the master device list with the
+ * highest id.
+ */
+ for (dev = dev_base; dev != NULL; dev = dev->next)
+ {
+ /* Be suspicious of the other devices. Who knows what
+ was what has happened to them since we saw them
+ last. */
+ if (dev->name != NULL)
+ {
+ /* Check for matching device type. */
+ if (strncmp(name_fmt, dev->name, type_len) == 0
+ && isdigit(dev->name[type_len]))
+ {
+ /* Device type matches, parse id. */
+ ptr = (char *)(dev->name + type_len);
+ n = (int)simple_strtoul(ptr, NULL, 0);
+
+ /* Remeber the parsed id if it's the
+ highest found. */
+ if (n > id)
+ id = n;
+ }
+ }
+ }
+
+ /* Write the new name. */
+ sprintf(device->name, name_fmt, id);
+
+ return id;
}
- return -ENFILE; /* Over 100 of the things .. bail out! */
+ else
+ /* No format string indicator found in arg name_fmt. */
+ return -EINVAL;
}
struct device *dev_alloc(const char *name, int *err)
-
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