Messages in this thread Patch in this message | | | Date | Thu, 19 Oct 2000 21:50:48 +0200 (CEST) | From | Geert Uytterhoeven <> | Subject | real_root_dev |
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`real_root_dev' must be `int', not `kdev_t'.
The reason for this is that we still have (in <linux/kdev_t.h>):
typedef unsigned short kdev_t;
while kernel/sysctl.c has the following line:
{KERN_REALROOTDEV, "real-root-dev", &real_root_dev, sizeof(int), 0644, NULL, &proc_dointvec},
This causes a nice endianness problem on big-endian machines. It can even cause weird results on little-endian machines where the alignment rule for int is a 2 byte-boundary.
We've had this patch in the m68k tree since ages (at least 2.0.x), so it's time to share it to the world :-) I think it was originally by Andreas Schwab.
--- linux-2.4.0-test10-pre3/init/main.c Sat Sep 23 17:31:22 2000 +++ geert-real_root_dev-2.4.0-test10-pre3/init/main.c Thu Oct 19 21:39:07 2000 @@ -124,7 +124,7 @@ int rows, cols; #ifdef CONFIG_BLK_DEV_INITRD -kdev_t real_root_dev; +int real_root_dev; /* MUST be int for sysctl! */ #endif int root_mountflags = MS_RDONLY; @@ -717,7 +717,7 @@ #ifdef CONFIG_BLK_DEV_INITRD root_mountflags = real_root_mountflags; - if (mount_initrd && ROOT_DEV != real_root_dev + if (mount_initrd && ROOT_DEV != (kdev_t)real_root_dev && MAJOR(ROOT_DEV) == RAMDISK_MAJOR && MINOR(ROOT_DEV) == 0) { int error; int i, pid; @@ -725,9 +725,9 @@ pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD); if (pid>0) while (pid != wait(&i)); - if (MAJOR(real_root_dev) != RAMDISK_MAJOR - || MINOR(real_root_dev) != 0) { - error = change_root(real_root_dev,"/initrd"); + if (MAJOR((kdev_t)real_root_dev) != RAMDISK_MAJOR + || MINOR((kdev_t)real_root_dev) != 0) { + error = change_root((kdev_t)real_root_dev,"/initrd"); if (error) printk(KERN_ERR "Change root to /initrd: " "error %d\n",error); --- linux-2.4.0-test10-pre3/include/linux/devfs_fs_kernel.h Tue Jul 18 14:07:34 2000 +++ geert-real_root_dev-2.4.0-test10-pre3/include/linux/devfs_fs_kernel.h Thu Oct 19 21:38:06 2000 @@ -46,7 +46,7 @@ #ifdef CONFIG_BLK_DEV_INITRD -# define ROOT_DEVICE_NAME ((real_root_dev ==ROOT_DEV) ? root_device_name:NULL) +# define ROOT_DEVICE_NAME (((kdev_t)real_root_dev ==ROOT_DEV) ? root_device_name:NULL) #else # define ROOT_DEVICE_NAME root_device_name #endif --- linux-2.4.0-test10-pre3/include/linux/fs.h Sat Oct 14 19:03:33 2000 +++ geert-real_root_dev-2.4.0-test10-pre3/include/linux/fs.h Thu Oct 19 21:38:21 2000 @@ -1228,7 +1228,7 @@ extern void mount_root(void); #ifdef CONFIG_BLK_DEV_INITRD -extern kdev_t real_root_dev; +extern int real_root_dev; extern int change_root(kdev_t, const char *); #endif --- linux-2.4.0-test10-pre3/drivers/block/rd.c Tue Jul 18 14:08:53 2000 +++ geert-real_root_dev-2.4.0-test10-pre3/drivers/block/rd.c Thu Oct 19 21:37:58 2000 @@ -704,7 +704,7 @@ static void __init rd_load_disk(int n) { #ifdef CONFIG_BLK_DEV_INITRD - extern kdev_t real_root_dev; + extern int real_root_dev; #endif if (rd_doload == 0) @@ -712,7 +712,7 @@ if (MAJOR(ROOT_DEV) != FLOPPY_MAJOR #ifdef CONFIG_BLK_DEV_INITRD - && MAJOR(real_root_dev) != FLOPPY_MAJOR + && MAJOR((kdev_t)real_root_dev) != FLOPPY_MAJOR #endif ) return; @@ -724,8 +724,8 @@ #ifdef CONFIG_MAC_FLOPPY if(MAJOR(ROOT_DEV) == FLOPPY_MAJOR) swim3_fd_eject(MINOR(ROOT_DEV)); - else if(MAJOR(real_root_dev) == FLOPPY_MAJOR) - swim3_fd_eject(MINOR(real_root_dev)); + else if(MAJOR((kdev_t)real_root_dev) == FLOPPY_MAJOR) + swim3_fd_eject(MINOR((kdev_t)real_root_dev)); #endif printk(KERN_NOTICE "VFS: Insert root floppy disk to be loaded into RAM disk and press ENTER\n"); Gr{oetje,eeting}s, Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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