Re: [PATCH 1/3] 2.6.8-rc4-mm1 - Fix UML build

From: Jeff Dike
Date: Tue Aug 17 2004 - 13:16:50 EST

akpm@xxxxxxxx said:
> Thanks. Where do we stand now with getting all this stuff merged up?
> Are the patches in -mm suitable? Did the controversial blockdev stuff
> get cleaned up? (it looks like it did...).

Not really, the code is still there but it's not built. Below is a patch
which removes it totally.

I also have to get rid of ghash.h and fix some inappropriate intimacy between
one of the drivers and VFS.

I'd also wouldn't mind breaking up the big UML patch into somewhat more sane
pieces. Can I do something like break pieces off it, send them plus the
smaller big patch, and have you subsititute them for the current big patch?

Is that preferable to dropping the current patches on Linus, or would you
rather send him what you have, in more or less its current form, once it's
been tidied up?

Jeff

Index: 2.6.8.1-mm1/arch/um/Kconfig_block
===================================================================
--- 2.6.8.1-mm1.orig/arch/um/Kconfig_block 2004-08-17 13:48:15.000000000 -0400
+++ 2.6.8.1-mm1/arch/um/Kconfig_block 2004-08-17 13:48:19.000000000 -0400
@@ -29,19 +29,9 @@
wise choice too. In all other cases (for example, if you're just
playing around with User-Mode Linux) you can choose N.

-# Turn this back on when the driver actually works
-#
-#config BLK_DEV_COW
-# tristate "COW block device"
-# help
-# This is a layered driver which sits above two other block devices.
-# One is read-only, and the other is a read-write layer which stores
-# all changes. This provides the illusion that the read-only layer
-# can be mounted read-write and changed.
-
config BLK_DEV_COW_COMMON
bool
- default BLK_DEV_COW || BLK_DEV_UBD
+ default BLK_DEV_UBD

config BLK_DEV_LOOP
tristate "Loopback device support"
Index: 2.6.8.1-mm1/arch/um/drivers/Makefile
===================================================================
--- 2.6.8.1-mm1.orig/arch/um/drivers/Makefile 2004-08-17 00:09:30.000000000 -0400
+++ 2.6.8.1-mm1/arch/um/drivers/Makefile 2004-08-17 13:48:52.000000000 -0400
@@ -39,7 +39,6 @@
obj-$(CONFIG_TTY_CHAN) += tty.o
obj-$(CONFIG_XTERM_CHAN) += xterm.o xterm_kern.o
obj-$(CONFIG_UML_WATCHDOG) += harddog.o
-obj-$(CONFIG_BLK_DEV_COW) += cow_kern.o
obj-$(CONFIG_BLK_DEV_COW_COMMON) += cow_user.o

obj-y += stdio_console.o $(CHAN_OBJS)
Index: 2.6.8.1-mm1/arch/um/drivers/cow_kern.c
===================================================================
--- 2.6.8.1-mm1.orig/arch/um/drivers/cow_kern.c 2004-08-17 00:09:30.000000000 -0400
+++ 2.6.8.1-mm1/arch/um/drivers/cow_kern.c 2003-09-15 09:40:47.000000000 -0400
@@ -1,630 +0,0 @@
-#define COW_MAJOR 60
-#define MAJOR_NR COW_MAJOR
-
-#include <linux/stddef.h>
-#include <linux/kernel.h>
-#include <linux/ctype.h>
-#include <linux/stat.h>
-#include <linux/vmalloc.h>
-#include <linux/blkdev.h>
-#include <linux/blk.h>
-#include <linux/fs.h>
-#include <linux/genhd.h>
-#include <linux/devfs_fs.h>
-#include <asm/uaccess.h>
-#include "2_5compat.h"
-#include "cow.h"
-#include "ubd_user.h"
-
-#define COW_SHIFT 4
-
-struct cow {
- int count;
- char *cow_path;
- dev_t cow_dev;
- struct block_device *cow_bdev;
- char *backing_path;
- dev_t backing_dev;
- struct block_device *backing_bdev;
- int sectorsize;
- unsigned long *bitmap;
- unsigned long bitmap_len;
- int bitmap_offset;
- int data_offset;
- devfs_handle_t devfs;
- struct semaphore sem;
- struct semaphore io_sem;
- atomic_t working;
- spinlock_t io_lock;
- struct buffer_head *bh;
- struct buffer_head *bhtail;
- void *end_io;
-};
-
-#define DEFAULT_COW { \
- .count = 0, \
- .cow_path = NULL, \
- .cow_dev = 0, \
- .backing_path = NULL, \
- .backing_dev = 0, \
- .bitmap = NULL, \
- .bitmap_len = 0, \
- .bitmap_offset = 0, \
- .data_offset = 0, \
- .devfs = NULL, \
- .working = ATOMIC_INIT(0), \
- .io_lock = SPIN_LOCK_UNLOCKED, \
-}
-
-#define MAX_DEV (8)
-#define MAX_MINOR (MAX_DEV << COW_SHIFT)
-
-struct cow cow_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_COW };
-
-/* Not modified by this driver */
-static int blk_sizes[MAX_MINOR] = { [ 0 ... MAX_MINOR - 1 ] = BLOCK_SIZE };
-static int hardsect_sizes[MAX_MINOR] = { [ 0 ... MAX_MINOR - 1 ] = 512 };
-
-/* Protected by cow_lock */
-static int sizes[MAX_MINOR] = { [ 0 ... MAX_MINOR - 1 ] = 0 };
-
-static struct hd_struct cow_part[MAX_MINOR] =
- { [ 0 ... MAX_MINOR - 1 ] = { 0, 0, 0 } };
-
-/* Protected by io_request_lock */
-static request_queue_t *cow_queue;
-
-static int cow_open(struct inode *inode, struct file *filp);
-static int cow_release(struct inode * inode, struct file * file);
-static int cow_ioctl(struct inode * inode, struct file * file,
- unsigned int cmd, unsigned long arg);
-static int cow_revalidate(kdev_t rdev);
-
-static struct block_device_operations cow_blops = {
- .open = cow_open,
- .release = cow_release,
- .ioctl = cow_ioctl,
- .revalidate = cow_revalidate,
-};
-
-/* Initialized in an initcall, and unchanged thereafter */
-devfs_handle_t cow_dir_handle;
-
-#define INIT_GENDISK(maj, name, parts, shift, bsizes, max, blops) \
-{ \
- .major = maj, \
- .major_name = name, \
- .minor_shift = shift, \
- .max_p = 1 << shift, \
- .part = parts, \
- .sizes = bsizes, \
- .nr_real = max, \
- .real_devices = NULL, \
- .next = NULL, \
- .fops = blops, \
- .de_arr = NULL, \
- .flags = 0 \
-}
-
-static spinlock_t cow_lock = SPIN_LOCK_UNLOCKED;
-
-static struct gendisk cow_gendisk = INIT_GENDISK(MAJOR_NR, "cow", cow_part,
- COW_SHIFT, sizes, MAX_DEV,
- &cow_blops);
-
-static int cow_add(int n)
-{
- struct cow *dev = &cow_dev[n];
- char name[sizeof("nnnnnn\0")];
- int err = -ENODEV;
-
- if(dev->cow_path == NULL)
- goto out;
-
- sprintf(name, "%d", n);
- dev->devfs = devfs_register(cow_dir_handle, name, DEVFS_FL_REMOVABLE,
- MAJOR_NR, n << COW_SHIFT, S_IFBLK |
- S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP,
- &cow_blops, NULL);
-
- init_MUTEX_LOCKED(&dev->sem);
- init_MUTEX(&dev->io_sem);
-
- return(0);
-
- out:
- return(err);
-}
-
-/*
- * Add buffer_head to back of pending list
- */
-static void cow_add_bh(struct cow *cow, struct buffer_head *bh)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&cow->io_lock, flags);
- if(cow->bhtail != NULL){
- cow->bhtail->b_reqnext = bh;
- cow->bhtail = bh;
- }
- else {
- cow->bh = bh;
- cow->bhtail = bh;
- }
- spin_unlock_irqrestore(&cow->io_lock, flags);
-}
-
-/*
-* Grab first pending buffer
-*/
-static struct buffer_head *cow_get_bh(struct cow *cow)
-{
- struct buffer_head *bh;
-
- spin_lock_irq(&cow->io_lock);
- bh = cow->bh;
- if(bh != NULL){
- if(bh == cow->bhtail)
- cow->bhtail = NULL;
- cow->bh = bh->b_reqnext;
- bh->b_reqnext = NULL;
- }
- spin_unlock_irq(&cow->io_lock);
-
- return(bh);
-}
-
-static void cow_handle_bh(struct cow *cow, struct buffer_head *bh,
- struct buffer_head **cow_bh, int ncow_bh)
-{
- int i;
-
- if(ncow_bh > 0)
- ll_rw_block(WRITE, ncow_bh, cow_bh);
-
- for(i = 0; i < ncow_bh ; i++){
- wait_on_buffer(cow_bh[i]);
- brelse(cow_bh[i]);
- }
-
- ll_rw_block(WRITE, 1, &bh);
- brelse(bh);
-}
-
-static struct buffer_head *cow_new_bh(struct cow *dev, int sector)
-{
- struct buffer_head *bh;
-
- sector = (dev->bitmap_offset + sector / 8) / dev->sectorsize;
- bh = getblk(dev->cow_dev, sector, dev->sectorsize);
- memcpy(bh->b_data, dev->bitmap + sector / (8 * sizeof(dev->bitmap[0])),
- dev->sectorsize);
- return(bh);
-}
-
-/* Copied from loop.c, needed to avoid deadlocking in make_request. */
-
-static int cow_thread(void *data)
-{
- struct cow *dev = data;
- struct buffer_head *bh;
-
- daemonize();
- exit_files(current);
-
- sprintf(current->comm, "cow%d", dev - cow_dev);
-
- spin_lock_irq(&current->sigmask_lock);
- sigfillset(&current->blocked);
- flush_signals(current);
- spin_unlock_irq(&current->sigmask_lock);
-
- atomic_inc(&dev->working);
-
- current->policy = SCHED_OTHER;
- current->nice = -20;
-
- current->flags |= PF_NOIO;
-
- /*
- * up sem, we are running
- */
- up(&dev->sem);
-
- for(;;){
- int start, len, nbh, i, update_bitmap = 0;
- struct buffer_head *cow_bh[2];
-
- down_interruptible(&dev->io_sem);
- /*
- * could be upped because of tear-down, not because of
- * pending work
- */
- if(!atomic_read(&dev->working))
- break;
-
- bh = cow_get_bh(dev);
- if(bh == NULL){
- printk(KERN_ERR "cow: missing bh\n");
- continue;
- }
-
- start = bh->b_blocknr * bh->b_size / dev->sectorsize;
- len = bh->b_size / dev->sectorsize;
- for(i = 0; i < len ; i++){
- if(ubd_test_bit(start + i,
- (unsigned char *) dev->bitmap))
- continue;
-
- update_bitmap = 1;
- ubd_set_bit(start + i, (unsigned char *) dev->bitmap);
- }
-
- cow_bh[0] = NULL;
- cow_bh[1] = NULL;
- nbh = 0;
- if(update_bitmap){
- cow_bh[0] = cow_new_bh(dev, start);
- nbh++;
- if(start / dev->sectorsize !=
- (start + len) / dev->sectorsize){
- cow_bh[1] = cow_new_bh(dev, start + len);
- nbh++;
- }
- }
-
- bh->b_dev = dev->cow_dev;
- bh->b_blocknr += dev->data_offset / dev->sectorsize;
-
- cow_handle_bh(dev, bh, cow_bh, nbh);
-
- /*
- * upped both for pending work and tear-down, lo_pending
- * will hit zero then
- */
- if(atomic_dec_and_test(&dev->working))
- break;
- }
-
- up(&dev->sem);
- return(0);
-}
-
-static int cow_make_request(request_queue_t *q, int rw, struct buffer_head *bh)
-{
- struct cow *dev;
- int n, minor;
-
- minor = MINOR(bh->b_rdev);
- n = minor >> COW_SHIFT;
- dev = &cow_dev[n];
-
- dev->end_io = NULL;
- if(ubd_test_bit(bh->b_rsector, (unsigned char *) dev->bitmap)){
- bh->b_rdev = dev->cow_dev;
- bh->b_rsector += dev->data_offset / dev->sectorsize;
- }
- else if(rw == WRITE){
- bh->b_dev = dev->cow_dev;
- bh->b_blocknr += dev->data_offset / dev->sectorsize;
-
- cow_add_bh(dev, bh);
- up(&dev->io_sem);
- return(0);
- }
- else {
- bh->b_rdev = dev->backing_dev;
- }
-
- return(1);
-}
-
-int cow_init(void)
-{
- int i;
-
- cow_dir_handle = devfs_mk_dir (NULL, "cow", NULL);
- if (devfs_register_blkdev(MAJOR_NR, "cow", &cow_blops)) {
- printk(KERN_ERR "cow: unable to get major %d\n", MAJOR_NR);
- return -1;
- }
- read_ahead[MAJOR_NR] = 8; /* 8 sector (4kB) read-ahead */
- blksize_size[MAJOR_NR] = blk_sizes;
- blk_size[MAJOR_NR] = sizes;
- INIT_HARDSECT(hardsect_size, MAJOR_NR, hardsect_sizes);
-
- cow_queue = BLK_DEFAULT_QUEUE(MAJOR_NR);
- blk_init_queue(cow_queue, NULL);
- INIT_ELV(cow_queue, &cow_queue->elevator);
- blk_queue_make_request(cow_queue, cow_make_request);
-
- add_gendisk(&cow_gendisk);
-
- for(i=0;i<MAX_DEV;i++)
- cow_add(i);
-
- return(0);
-}
-
-__initcall(cow_init);
-
-static int reader(__u64 start, char *buf, int count, void *arg)
-{
- dev_t dev = *((dev_t *) arg);
- struct buffer_head *bh;
- __u64 block;
- int cur, offset, left, n, blocksize = get_hardsect_size(dev);
-
- if(blocksize == 0)
- panic("Zero blocksize");
-
- block = start / blocksize;
- offset = start % blocksize;
- left = count;
- cur = 0;
- while(left > 0){
- n = (left > blocksize) ? blocksize : left;
-
- bh = bread(dev, block, (n < 512) ? 512 : n);
- if(bh == NULL)
- return(-EIO);
-
- n -= offset;
- memcpy(&buf[cur], bh->b_data + offset, n);
- block++;
- left -= n;
- cur += n;
- offset = 0;
- brelse(bh);
- }
-
- return(count);
-}
-
-static int cow_open(struct inode *inode, struct file *filp)
-{
- int (*dev_ioctl)(struct inode *, struct file *, unsigned int,
- unsigned long);
- mm_segment_t fs;
- struct cow *dev;
- __u64 size;
- __u32 version, align;
- time_t mtime;
- char *backing_file;
- int n, offset, err = 0;
-
- n = DEVICE_NR(inode->i_rdev);
- if(n >= MAX_DEV)
- return(-ENODEV);
- dev = &cow_dev[n];
- offset = n << COW_SHIFT;
-
- spin_lock(&cow_lock);
-
- if(dev->count == 0){
- dev->cow_dev = name_to_kdev_t(dev->cow_path);
- if(dev->cow_dev == 0){
- printk(KERN_ERR "cow_open - name_to_kdev_t(\"%s\") "
- "failed\n", dev->cow_path);
- err = -ENODEV;
- }
-
- dev->backing_dev = name_to_kdev_t(dev->backing_path);
- if(dev->backing_dev == 0){
- printk(KERN_ERR "cow_open - name_to_kdev_t(\"%s\") "
- "failed\n", dev->backing_path);
- err = -ENODEV;
- }
-
- if(err)
- goto out;
-
- dev->cow_bdev = bdget(dev->cow_dev);
- if(dev->cow_bdev == NULL){
- printk(KERN_ERR "cow_open - bdget(\"%s\") failed\n",
- dev->cow_path);
- err = -ENOMEM;
- }
- dev->backing_bdev = bdget(dev->backing_dev);
- if(dev->backing_bdev == NULL){
- printk(KERN_ERR "cow_open - bdget(\"%s\") failed\n",
- dev->backing_path);
- err = -ENOMEM;
- }
-
- if(err)
- goto out;
-
- err = blkdev_get(dev->cow_bdev, FMODE_READ|FMODE_WRITE, 0,
- BDEV_RAW);
- if(err){
- printk("cow_open - blkdev_get of COW device failed, "
- "error = %d\n", err);
- goto out;
- }
-
- err = blkdev_get(dev->backing_bdev, FMODE_READ, 0, BDEV_RAW);
- if(err){
- printk("cow_open - blkdev_get of backing device "
- "failed, error = %d\n", err);
- goto out;
- }
-
- err = read_cow_header(reader, &dev->cow_dev, &version,
- &backing_file, &mtime, &size,
- &dev->sectorsize, &align,
- &dev->bitmap_offset);
- if(err){
- printk(KERN_ERR "cow_open - read_cow_header failed, "
- "err = %d\n", err);
- goto out;
- }
-
- cow_sizes(version, size, dev->sectorsize, align,
- dev->bitmap_offset, &dev->bitmap_len,
- &dev->data_offset);
- dev->bitmap = (void *) vmalloc(dev->bitmap_len);
- if(dev->bitmap == NULL){
- err = -ENOMEM;
- printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
- goto out;
- }
- flush_tlb_kernel_vm();
-
- err = reader(dev->bitmap_offset, (char *) dev->bitmap,
- dev->bitmap_len, &dev->cow_dev);
- if(err < 0){
- printk(KERN_ERR "Failed to read COW bitmap\n");
- vfree(dev->bitmap);
- goto out;
- }
-
- dev_ioctl = dev->backing_bdev->bd_op->ioctl;
- fs = get_fs();
- set_fs(KERNEL_DS);
- err = (*dev_ioctl)(inode, filp, BLKGETSIZE,
- (unsigned long) &sizes[offset]);
- set_fs(fs);
- if(err){
- printk(KERN_ERR "cow_open - BLKGETSIZE failed, "
- "error = %d\n", err);
- goto out;
- }
-
- kernel_thread(cow_thread, dev,
- CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
- down(&dev->sem);
- }
- dev->count++;
- out:
- spin_unlock(&cow_lock);
- return(err);
-}
-
-static int cow_release(struct inode * inode, struct file * file)
-{
- struct cow *dev;
- int n, err;
-
- n = DEVICE_NR(inode->i_rdev);
- if(n >= MAX_DEV)
- return(-ENODEV);
- dev = &cow_dev[n];
-
- spin_lock(&cow_lock);
-
- if(--dev->count > 0)
- goto out;
-
- err = blkdev_put(dev->cow_bdev, BDEV_RAW);
- if(err)
- printk("cow_release - blkdev_put of cow device failed, "
- "error = %d\n", err);
- bdput(dev->cow_bdev);
- dev->cow_bdev = 0;
-
- err = blkdev_put(dev->backing_bdev, BDEV_RAW);
- if(err)
- printk("cow_release - blkdev_put of backing device failed, "
- "error = %d\n", err);
- bdput(dev->backing_bdev);
- dev->backing_bdev = 0;
-
- out:
- spin_unlock(&cow_lock);
- return(0);
-}
-
-static int cow_ioctl(struct inode * inode, struct file * file,
- unsigned int cmd, unsigned long arg)
-{
- struct cow *dev;
- int (*dev_ioctl)(struct inode *, struct file *, unsigned int,
- unsigned long);
- int n;
-
- n = DEVICE_NR(inode->i_rdev);
- if(n >= MAX_DEV)
- return(-ENODEV);
- dev = &cow_dev[n];
-
- dev_ioctl = dev->backing_bdev->bd_op->ioctl;
- return((*dev_ioctl)(inode, file, cmd, arg));
-}
-
-static int cow_revalidate(kdev_t rdev)
-{
- printk(KERN_ERR "Need to implement cow_revalidate\n");
- return(0);
-}
-
-static int parse_unit(char **ptr)
-{
- char *str = *ptr, *end;
- int n = -1;
-
- if(isdigit(*str)) {
- n = simple_strtoul(str, &end, 0);
- if(end == str)
- return(-1);
- *ptr = end;
- }
- else if (('a' <= *str) && (*str <= 'h')) {
- n = *str - 'a';
- str++;
- *ptr = str;
- }
- return(n);
-}
-
-static int cow_setup(char *str)
-{
- struct cow *dev;
- char *cow_name, *backing_name;
- int unit;
-
- unit = parse_unit(&str);
- if(unit < 0){
- printk(KERN_ERR "cow_setup - Couldn't parse unit number\n");
- return(1);
- }
-
- if(*str != '='){
- printk(KERN_ERR "cow_setup - Missing '=' after unit "
- "number\n");
- return(1);
- }
- str++;
-
- cow_name = str;
- backing_name = strchr(str, ',');
- if(backing_name == NULL){
- printk(KERN_ERR "cow_setup - missing backing device name\n");
- return(0);
- }
- *backing_name = '\0';
- backing_name++;
-
- spin_lock(&cow_lock);
-
- dev = &cow_dev[unit];
- dev->cow_path = cow_name;
- dev->backing_path = backing_name;
-
- spin_unlock(&cow_lock);
- return(0);
-}
-
-__setup("cow", cow_setup);
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only. This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */

-
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