Patch series to remove devfs [00/22]

As everyone knows[1], devfs is going to be removed from the kernel soon. To accomplish this, here is a series of patches (22 in all) that do just that. Surprisingly enough, devfs was almost everywhere in the kernel, that's why it takes so many patches :)

Anyway, here's the whole series against 2.6.12-rc6-git4. If some of them don't make it through to lkml (due to size restrictions, or just failing on a "taste" filter), you can find them all at:

	http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/gregkh-05-devfs/

along with a quilt series file to apply them with.

Andrew, please do not pick these up for your -mm tree. Odds are it will just cause too many conflicts to make it worth your while :)

Comments welcome.

Oh, and the best part? Here's the summary of the diffstat:

  222 files changed, 112 insertions(+), 8545 deletions(-)

It's nice to remove code from the kernel for a change...

thanks,

greg k-h

[1] What? You don't know this? Didn't you get the memo[2]? Did you miss the huge flame war almost a year ago[3]? Are you living under a rock[4]?
[2] http://lxr.linux.no/source/Documentation/feature-removal-schedule.txt
[3] http://thread.gmane.org/gmane.linux.kernel/219278
[4] http://www.balloonplanet.com/shop/images/products/product_1788_small.jpg

Please don't remove the !CONFIG_DEVFS_FS dummies from devfs_fs_kernel.h.

I'm sure some driver maintainers will want to keep the functions in their code because they share their drivers between 2.4 and 2.6 .

Keeping a devfs_fs_kernel.h with dummy functions doesn't hurt, but it prevents version #ifdef's in drivers and/or the same dummy functions in some subsystem specific headers.

cu
Adrian

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

All drivers should be in the mainline kernel tree, so why would they need this? Remember, out-of-the-tree drivers are on their own...

thanks,

greg k-h

I'm talking about drivers in the mainline kernel tree.

In some cases the driver author supports both 2.4 and 2.6 and prefers to support them in one file. Sometimes he submits the latest version of his driver to Marcelo or Linus.

If you remove the global function dummies, you force every driver maintainer who works this way to add the function dummies to their drivers.

Yes, there are many places where 2.4 and 2.6 are not source compatible for good reasons. But if the effort for maintaining compatibility between 2.4 and 2.6 in one area is as easy as keeping a header file with some dummy funtions it's worth considering.

And keeping the compatibility stuff in one file instead of spreaded through the kernel sources makes the cleanup to remove the last occurences a few years from now easier.

cu
Adrian

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

The devfs calls for 2.4 and 2.6 are totally incompatible. And there's a trivial way to support both 2.4 and 2.6 in this area: don't support devfs at all, it always was marked either experimental or deprecated anyway.

OK, it seems I've missed how much devfs changed during 2.5 times...

Simply discard my emails in this thread.

cu
Adrian

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

How do these 2.4+2.6 drivers integrate with sysfs? Without proper 2.6-driver-core integration they will not work anyway.

Kay

The patch below fixes three compile errors and one compile warning after applying the devfs removal patches.

---

 drivers/ide/ide-tape.c |    1 -
 drivers/md/md.c        |    1 -
 init/do_mounts_md.c    |    2 +-
 init/do_mounts_rd.c    |    4 ++--
 4 files changed, 3 insertions(+), 5 deletions(-)

@@ -262,8 +262,8 @@
 {
 	if (rd_prompt)
 		change_floppy("root floppy disk to be loaded into RAM disk");
-	create_dev("/dev/root", ROOT_DEV, root_device_name);
-	create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n), NULL);
+	create_dev("/dev/root", ROOT_DEV);
+	create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 	return rd_load_image("/dev/root");
 }
 

@@ -275,7 +275,7 @@
 
 void __init md_run_setup(void)
 {
-	create_dev("/dev/md0", MKDEV(MD_MAJOR, 0), "md/0");
+	create_dev("/dev/md0", MKDEV(MD_MAJOR, 0));
 	if (raid_noautodetect)
 		printk(KERN_INFO "md: Skipping autodetection of RAID arrays. (raid=noautodetect)\n");
 	else {

@@ -4875,7 +4875,6 @@
 
 	idetape_setup(drive, tape, minor);
 
-	g->number = -1;
 	g->fops = &idetape_block_ops;
 	ide_register_region(g);
 

@@ -3947,7 +3947,6 @@
 {
 	mddev_t *mddev;
 	struct list_head *tmp;
-	int i;
 	blk_unregister_region(MKDEV(MAJOR_NR,0), MAX_MD_DEVS);
 	blk_unregister_region(MKDEV(mdp_major,0), MAX_MD_DEVS << MdpMinorShift);
 

Thanks a lot, I've incorporated these into my patch series.

greg k-h

You missed this for -mm, do not know if they apply to mainline:

@@ -20,7 +20,6 @@
 #include <linux/interrupt.h>
 #include <linux/blkdev.h>
 #include <linux/completion.h>
-#include <linux/devfs_fs_kernel.h>
 #include <linux/ioctl32.h>
 #include <linux/compat.h>
 #include <linux/chio.h>			/* here are all the ioctls */

@@ -940,8 +939,6 @@
 	if (init)
 		ch_init_elem(ch);
 
-	devfs_mk_cdev(MKDEV(SCSI_CHANGER_MAJOR,ch->minor),
-		      S_IFCHR | S_IRUGO | S_IWUGO, ch->name);
 	class_device_create(ch_sysfs_class,
 			    MKDEV(SCSI_CHANGER_MAJOR,ch->minor),
 			    dev, "s%s", ch->name);

@@ -974,7 +971,6 @@
 
 	class_device_destroy(ch_sysfs_class,
 			     MKDEV(SCSI_CHANGER_MAJOR,ch->minor));
-	devfs_remove(ch->name);
 	kfree(ch->dt);
 	kfree(ch);
 	ch_devcount--;

@@ -101,7 +101,6 @@
 #include <linux/moduleparam.h>
 #include <linux/blkdev.h>
 #include <linux/timer.h>
-#include <linux/devfs_fs_kernel.h>
 #include <linux/mc146818rtc.h>
 #include <linux/reboot.h>
 #include <linux/sched.h>

@@ -1654,7 +1653,6 @@
 **	int                     attached;		            %% # of high level drivers attached to this %%
 **	int                     access_count;	            %% Count of open channels/mounts %%
 **	void                    *hostdata;		            %% available to low-level driver %%
-**	devfs_handle_t          de;                         %% directory for the device %%
 **	char                    type;
 **	char                    scsi_level;
 **	char                    vendor[8], model[16], rev[4];

--
J.A. Magallon <jamagallon()able!es> \ Software is like sex:
werewolf!able!es \ It's better when it's free
Mandriva Linux release 2006.0 (Cooker) for i586
Linux 2.6.11-jam24 (gcc 4.0.0 (4.0.0-3mdk for Mandriva Linux release 2006.0))

This patch series was not for -mm, as my comments stated :)

But thanks for the patch anyway.

greg k-h

I shifted some offsets and am running it now...

--
J.A. Magallon <jamagallon()able!es> \ Software is like sex:
werewolf!able!es \ It's better when it's free
Mandriva Linux release 2006.0 (Cooker) for i586
Linux 2.6.11-jam25 (gcc 4.0.0 (4.0.0-3mdk for Mandriva Linux release 2006.0))