[PATCH] aacraid: Add kernel command line parameter parsing

[PATCH] aacraid: Add kernel command line parameter parsing

[Salyzyn, Mark]

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One shortcoming of the driver relationship with the kernel is that there
is no standard means of having the insmod parameters associated with a
driver to also be parsed and set by the kernel parameter line. The
enclosed patch is a proposal for the aacraid driver to pick up the
kernel parameter line, parse it, and then adjust the insmod parameters.

The format of the kernel parameter line is
	aacraid=<parm>:<value>[,<parm>:<value>]...

There may be a better way of providing this service via the kernel
without any modifications from the driver, since all the characteristics
of the insmod parameters are exported by the MODULE_PARM_* hints. Would
such mods be in insmod/modprobe and not in the kernel or driver?

Signed-off-by Mark Salyzyn <aacraid@adaptec.com>
---

Sincerely -- Mark Salyzyn
Illegitimi Non Carborundum

[-- Attachment #2: aacraid_command_line.patch --]
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diff -ru a/drivers/scsi/aacraid/aachba.c b/drivers/scsi/aacraid/aachba.c
--- a/drivers/scsi/aacraid/aachba.c	2007-01-30 16:24:35.781370236 -0500
+++ b/drivers/scsi/aacraid/aachba.c	2007-01-30 16:31:51.738891361 -0500
@@ -173,6 +173,51 @@
 int expose_physicals = -1;
 module_param(expose_physicals, int, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(expose_physicals, "Expose physical components of the arrays. -1=protect 0=off, 1=on");
+
+static char aacraid[COMMAND_LINE_SIZE];
+module_param_string(aacraid, aacraid, sizeof(aacraid), 0);
+MODULE_PARM_DESC(aacraid, "set the various published parameters of the aacraid driver with a syntax of aacraid=parm:value[,parm:value]...");
+
+static int aacraid_setup(char *str)
+{
+	int i;
+	char *key;
+	char *value;
+	struct {
+		char * option_name;
+		int * option_flag;
+		int option_value;
+	} options[] = {
+		{ "nondasd", &nondasd, 1 },
+		{ "dacmode", &dacmode, 1 },
+		{ "commit", &commit, 1 },
+		{ "acbsize", &acbsize, 8192 },
+		{ "expose_physicals", &expose_physicals, -1 },
+	};
+
+	if (str) while ((key = strsep(&str, ",.;"))) {
+		if (!*key)
+			continue;
+		if (((value = strchr(key, ':')))
+		 || ((value = strchr(key, '='))))
+			*value++ = '\0';
+		for (i = 0; i < (sizeof (options) / sizeof (options[0])); i++) {
+			if (strnicmp (key, options[i].option_name,
+			     strlen(options[i].option_name)) == 0) {
+				*options[i].option_flag
+				  = (value)
+				    ? simple_strtoul(value, NULL, 0)
+				    : options[i].option_value;
+				break;
+			}
+		}
+	}
+
+	return (1);
+}
+
+__setup("aacraid=", aacraid_setup);
+
 /**
  *	aac_get_config_status	-	check the adapter configuration
  *	@common: adapter to query
@@ -1148,6 +1193,69 @@
 				dev->name, dev->id,
 				le32_to_cpu(dev->adapter_info.serial[0]));
 	}
+	if (!aacraid[0])
+	{
+		char * command_line;
+		char *from, *to;
+#ifdef MODULE
+		extern struct proc_dir_entry proc_root;
+		struct proc_dir_entry * entry;
+
+		command_line = kmalloc(COMMAND_LINE_SIZE, GFP_KERNEL);
+		memset(command_line, 0, COMMAND_LINE_SIZE);
+		for (entry = proc_root.subdir;
+		  entry != (struct proc_dir_entry *)NULL;
+		  entry = entry->next) {
+			if ((entry->low_ino != 0)
+			 && (entry->namelen == 7)
+			 && (memcmp ("cmdline", entry->name, 7) == 0)) {
+				if (entry->read_proc != (int (*)(char *, char **, off_t, int, int *, void *))NULL) {
+					char * start = command_line;
+					int eof;
+					mm_segment_t fs;
+
+					fs = get_fs();
+					set_fs(get_ds());
+					lock_kernel();
+					entry->read_proc(command_line, &start,
+					  (off_t)0, COMMAND_LINE_SIZE-1, &eof,
+					  NULL);
+					unlock_kernel();
+					set_fs(fs);
+				}
+				break;
+			}
+		}
+#else
+		extern char saved_command_line[];
+		command_line = saved_command_line;
+#endif
+		memset(aacraid, 0, sizeof(aacraid));
+		from = command_line;
+		to = aacraid;
+		while (*from) {
+			if ((from[0] == 'a')
+			 && (from[1] == 'a')
+			 && (from[2] == 'c')
+			 && (from[3] == 'r')
+			 && (from[4] == 'a')
+			 && (from[5] == 'i')
+			 && (from[6] == 'd')
+			 && (from[7] == '=')) {
+				/* concatenate multiple instances of aacraid= */
+				if (to != aacraid)
+					*to++ = ',';
+				for (from += 8; *from && (*from != ' '); ++from)
+					*to++ =*from;
+			}
+			++from;
+		}
+#ifdef MODULE
+		kfree(command_line);
+#endif
+	}
+	if (aacraid[0])
+		aacraid_setup(aacraid);
 
 	dev->nondasd_support = 0;
 	dev->raid_scsi_mode = 0;

Re: [PATCH] aacraid: Add kernel command line parameter parsing

[Christoph Hellwig]

On Tue, Jan 30, 2007 at 04:42:28PM -0500, Salyzyn, Mark wrote:
> One shortcoming of the driver relationship with the kernel is that there
> is no standard means of having the insmod parameters associated with a
> driver to also be parsed and set by the kernel parameter line.

Actually there is.  In Linux 2.6 every module paramter can also specified
as <modulename>.<parameter> on the kernel command line.

Thus you patch is superflous and should not be applied.