From: Alan Cox <alan@redhat.com>
Subject: [PATCH RHEL5]: enabler for Dell ide-scsi blocker
Date: Thu, 7 Dec 2006 06:26:37 -0500
Bugzilla: 207248
Message-Id: <20061207112636.GD25121@devserv.devel.redhat.com>
Changelog: ide-scsi/ide-cdrom module load race fix


Our friends at Dell need ide-scsi autoloading for tape drives. This gets fun
if it beats the ide-cd module to your disks so add support for an option to
leave the CD devices untouched. In -mm, pushed by Andrew to Linus today.

Alan

---

Some people want to use ide_cd for CD-ROM but still dynamically load
ide-scsi for things like tape drives.  If you compile in the CD driver
this works out but if you want them modular you need an option to ensure
that whoever loads first the right things happen.

This replaces the original draft patch which leaked a scsi host reference

[akpm@osdl.org: add MODULE_PARM_DESC]
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 drivers/scsi/ide-scsi.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff -puN drivers/scsi/ide-scsi.c~ide_scsi-allow-it-to-be-used-for-non-cd-only drivers/scsi/ide-scsi.c
--- a/drivers/scsi/ide-scsi.c~ide_scsi-allow-it-to-be-used-for-non-cd-only
+++ a/drivers/scsi/ide-scsi.c
@@ -110,6 +110,7 @@ typedef struct ide_scsi_obj {
 } idescsi_scsi_t; 

 static DEFINE_MUTEX(idescsi_ref_mutex);
+static int idescsi_nocd;			/* Set by module param to skip cd */

 #define ide_scsi_g(disk) \
 	container_of((disk)->private_data, struct ide_scsi_obj, driver)
@@ -1127,6 +1128,9 @@ static int ide_scsi_probe(ide_drive_t *d
 		warned = 1;
 	}
 
+	if (idescsi_nocd && drive->media == ide_cdrom)
+		return -ENODEV;
+
 	if (!strstr("ide-scsi", drive->driver_req) ||
 	    !drive->present ||
 	    drive->media == ide_disk ||
@@ -1187,6 +1191,8 @@ static void __exit exit_idescsi_module(v
 	driver_unregister(&idescsi_driver.gen_driver);
 }
 
+module_param(idescsi_nocd, int, 0600);
+MODULE_PARM_DESC(idescsi_nocd, "Disable handling of CD-ROMs so they may be driven by ide-cd");
 module_init(init_idescsi_module);
 module_exit(exit_idescsi_module);
 MODULE_LICENSE("GPL");