[PATCH] kill scsihosts= boot parameter

[PATCH] kill scsihosts= boot parameter

[Christoph Hellwig]

This feature is seriously racy, and doesn't work under many
circumstances.  As we have proper ways to find devices by their
their locical naming (UUID, fs label) or physical connectivity
(scsidev, sysfs) it shouldn't be nessecary anymore.


diff -Nru a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
--- a/drivers/scsi/hosts.c	Thu Jun  5 12:05:04 2003
+++ b/drivers/scsi/hosts.c	Thu Jun  5 12:05:04 2003
@@ -49,96 +49,6 @@
 static spinlock_t scsi_host_list_lock = SPIN_LOCK_UNLOCKED;
 
 static int scsi_host_next_hn;		/* host_no for next new host */
-static char *scsihosts;
-
-MODULE_PARM(scsihosts, "s");
-MODULE_PARM_DESC(scsihosts, "scsihosts=driver1,driver2,driver3");
-#ifndef MODULE
-int __init scsi_setup(char *str)
-{
-	scsihosts = str;
-	return 1;
-}
-
-__setup("scsihosts=", scsi_setup);
-#endif
-
-/**
-  * scsi_find_host_by_num - get a Scsi_Host by host no
-  *
-  * @host_no:	host number to locate
-  *
-  * Return value:
-  *	A pointer to located Scsi_Host or NULL.
-  **/
-static struct Scsi_Host *scsi_find_host_by_num(unsigned short host_no)
-{
-	struct Scsi_Host *shost, *shost_found = NULL;
-
-	spin_lock(&scsi_host_list_lock);
-	list_for_each_entry(shost, &scsi_host_list, sh_list) {
-		if (shost->host_no > host_no) {
-			/*
-			 * The list is sorted.
-			 */
-			break;
-		} else if (shost->host_no == host_no) {
-			shost_found = shost;
-			break;
-		}
-	}
-	spin_unlock(&scsi_host_list_lock);
-	return shost_found;
-}
-
-/**
- * scsi_alloc_hostnum - choose new SCSI host number based on host name.
- * @name:	String to store in name field
- *
- * Return value:
- *	Pointer to a new Scsi_Host_Name
- **/
-static int scsi_alloc_host_num(const char *name)
-{
-	int hostnum;
-	int namelen;
-	const char *start, *end;
-
-	if (name) {
-		hostnum = 0;
-		namelen = strlen(name);
-		start = scsihosts; 
-		while (1) {
-			int hostlen;
-
-			if (start && start[0] != '\0') {
-				end = strpbrk(start, ",:");
-				if (end) {
-					hostlen = (end - start);
-					end++;
-				} else
-					hostlen = strlen(start);
-				/*
-				 * Look for a match on the scsihosts list.
-				 */
-				if ((hostlen == namelen) && 
-				    (strncmp(name, start, hostlen) == 0) && 
-				    (!scsi_find_host_by_num(hostnum)))
-					return hostnum;
-				start = end;
-			} else  {
-				/*
-				 * Look for any unused numbers.
-				 */
-				if (!scsi_find_host_by_num(hostnum))
-					return hostnum;
-			}
-			hostnum++;
-		}
-	} else
-		return scsi_host_next_hn++;
-}
-
 
 /**
  * scsi_tp_for_each_host - call function for each scsi host off a template
@@ -307,7 +217,7 @@
 
 	memset(shost, 0, sizeof(struct Scsi_Host) + xtr_bytes);
 
-	shost->host_no = scsi_alloc_host_num(shost_tp->proc_name);
+	shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
 
 	spin_lock_init(&shost->default_lock);
 	scsi_assign_lock(shost, &shost->default_lock);
@@ -514,26 +424,8 @@
  **/
 void scsi_host_put(struct Scsi_Host *shost)
 {
-
 	class_device_put(&shost->class_dev);
 	put_device(&shost->host_gendev);
-}
-
-/**
- * scsi_host_init - set up the scsi host number list based on any entries
- * scsihosts.
- **/
-void __init scsi_host_init(void)
-{
-	char *shost_hn;
-
-	shost_hn = scsihosts;
-	while (shost_hn) {
-		scsi_host_next_hn++;
-		shost_hn = strpbrk(shost_hn, ":,");
-		if (shost_hn)
-			shost_hn++;
-	}
 }
 
 void scsi_host_busy_inc(struct Scsi_Host *shost, Scsi_Device *sdev)
diff -Nru a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
--- a/drivers/scsi/scsi.c	Thu Jun  5 12:05:04 2003
+++ b/drivers/scsi/scsi.c	Thu Jun  5 12:05:04 2003
@@ -987,7 +987,6 @@
 	for (i = 0; i < NR_CPUS; i++)
 		INIT_LIST_HEAD(&done_q[i]);
 
-	scsi_host_init();
 	devfs_mk_dir("scsi");
 	open_softirq(SCSI_SOFTIRQ, scsi_softirq, NULL);
 	printk(KERN_NOTICE "SCSI subsystem initialized\n");

Re: [PATCH] kill scsihosts= boot parameter

[Ishikawa]

RE scshihosts=driver1,driver2,driver3...

Are we really sure we want to remove this?
There non-disk devices, say,  CDROMs and tapes, which
can't be handled by fs label and
I had a feeling that the userland tools that looks
at the physical connecivity might not be
so well standardized (or made available on every major distribution.).

Am I wrong about the latter (userland tools)?

I am afraid
that I will have to tweak a few system administration scripts 
if this feature is gone.
(I don't know why this works on a PC I manage well.)

> This feature is seriously racy, and doesn't work under many
> circumstances.  As we have proper ways to find devices by their
> their locical naming (UUID, fs label) or physical connectivity
> (scsidev, sysfs) it shouldn't be nessecary anymore.
> 


-- 
int main(void){int j=2003;/*(c)2003 cishikawa. */
char t[] ="<CI> @abcdefghijklmnopqrstuvwxyz.,\n\"";
char *i ="g>qtCIuqivb,gCwe\np@.ietCIuqi\"tqkvv is>dnamz";
while(*i)((j+=strchr(t,*i++)-(int)t),(j%=sizeof t-1),
(putchar(t[j])));return 0;}/* under GPL */