Enhance the Linux emulation layer to make MegaRAID SAS managements tool happy.

Add back in a scheme to emulate old type major/minor numbers via hooks into
stat, linprocfs to return major/minors that Linux app's expect.  Currently
only /dev/null is always registered.  Drivers can register via the Linux
type shim similar to the ioctl shim but by using
linux_device_register_handler/linux_device_unregister_handler functions.
The structure is:

    struct linux_device_handler {
        char    *bsd_driver_name;
        char    *linux_driver_name;
        char    *bsd_device_name;
        char    *linux_device_name;
        int     linux_major;
        int     linux_minor;
        int     linux_char_device;
    };

Linprocfs uses this to display the major number of the driver.  The
soon to be available linsysfs will use it to fill in the driver name.
Linux_stat uses it to translate the major/minor into Linux type values.

Note major numbers are dynamically assigned via passing in a -1 for
the major number so we don't need to keep track of them.

This is somewhat needed due to us switching to our devfs.  MegaCli
will not run until I add in the linsysfs and mfi Linux compat changes.

Sponsored by:	IronPort Systems

1 files changed, 137 insertions, 0 deletions

diff --git a/sys/compat/linux/linux_util.c b/sys/compat/linux/linux_util.c
index b0a639167329..09c51311dc7c 100644
--- a/sys/compat/linux/linux_util.c
+++ b/sys/compat/linux/linux_util.c
@@ -33,8 +33,10 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/bus.h>
 #include <sys/lock.h>
 #include <sys/malloc.h>
+#include <sys/linker_set.h>
 #include <sys/mutex.h>
 #include <sys/namei.h>
 #include <sys/proc.h>
@@ -82,3 +84,138 @@ linux_msg(const struct thread *td, const char *fmt, ...)
 	va_end(ap);
 	printf("\n");
 }
+
+MALLOC_DECLARE(M_LINUX);
+
+struct device_element
+{
+	TAILQ_ENTRY(device_element) list;
+	struct linux_device_handler entry;
+};
+
+static TAILQ_HEAD(, device_element) devices =
+	TAILQ_HEAD_INITIALIZER(devices);
+
+static struct linux_device_handler null_handler =
+	{ "mem", "mem", "null", "null", 1, 3, 1};
+
+DATA_SET(linux_device_handler_set, null_handler);
+
+char *
+linux_driver_get_name_dev(device_t dev)
+{
+	struct device_element *de;
+	const char *device_name = device_get_name(dev);
+
+	if (device_name == NULL)
+		return NULL;
+	TAILQ_FOREACH(de, &devices, list) {
+		if (strcmp(device_name, de->entry.bsd_driver_name) == 0)
+			return (de->entry.linux_driver_name);
+	}
+
+	return NULL;
+}
+
+int
+linux_driver_get_major_minor(char *node, int *major, int *minor)
+{
+	struct device_element *de;
+
+	if (node == NULL || major == NULL || minor == NULL)
+		return 1;
+	TAILQ_FOREACH(de, &devices, list) {
+		if (strcmp(node, de->entry.bsd_device_name) == 0) {
+			*major = de->entry.linux_major;
+			*minor = de->entry.linux_minor;
+			return 0;
+		}
+	}
+
+	return 1;
+}
+
+char *
+linux_get_char_devices()
+{
+	struct device_element *de;
+	char *temp, *string, *last;
+	char formated[256];
+	int current_size = 0, string_size = 1024;
+
+	MALLOC(string, char *, string_size, M_LINUX, M_WAITOK);
+	string[0] = '\000';
+	last = "";
+	TAILQ_FOREACH(de, &devices, list) {
+		if (!de->entry.linux_char_device)
+			continue;
+		temp = string;
+		if (strcmp(last, de->entry.bsd_driver_name) != 0) {
+			last = de->entry.bsd_driver_name;
+
+			snprintf(formated, sizeof(formated), "%3d %s\n",
+				 de->entry.linux_major,
+				 de->entry.linux_device_name);
+			if (strlen(formated) + current_size
+			    >= string_size) {
+				string_size *= 2;
+				MALLOC(string, char *, string_size,
+				    M_LINUX, M_WAITOK);
+				bcopy(temp, string, current_size);
+				FREE(temp, M_LINUX);
+			}
+			strcat(string, formated);
+			current_size = strlen(string);
+		}
+	}
+
+	return string;
+}
+
+void
+linux_free_get_char_devices(char *string)
+{
+	FREE(string, M_LINUX);
+}
+
+static int linux_major_starting = 200;
+
+int
+linux_device_register_handler(struct linux_device_handler *d)
+{
+	struct device_element *de;
+
+	if (d == NULL)
+		return (EINVAL);
+
+	MALLOC(de, struct device_element *, sizeof(*de),
+	    M_LINUX, M_WAITOK);
+	if (d->linux_major < 0) {
+		d->linux_major = linux_major_starting++;
+	}
+	bcopy(d, &de->entry, sizeof(*d));
+
+	/* Add the element to the list, sorted on span. */
+	TAILQ_INSERT_TAIL(&devices, de, list);
+
+	return (0);
+}
+
+int
+linux_device_unregister_handler(struct linux_device_handler *d)
+{
+	struct device_element *de;
+
+	if (d == NULL)
+		return (EINVAL);
+
+	TAILQ_FOREACH(de, &devices, list) {
+		if (bcmp(d, &de->entry, sizeof(*d)) == 0) {
+			TAILQ_REMOVE(&devices, de, list);
+			FREE(de, M_LINUX);
+			return (0);
+		}
+	}
+
+	return (EINVAL);
+}