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authorDavid Howells <dhowells@redhat.com>2006-09-30 14:45:40 -0400
committerJens Axboe <axboe@nelson.home.kernel.dk>2006-09-30 14:52:31 -0400
commit9361401eb7619c033e2394e4f9f6d410d6719ac7 (patch)
tree04b94a71f2366988c17740d1c16cfbdec41d5d2e /fs/proc
parentd366e40a1cabd453be6e2609caa7e12f9ca17b1f (diff)
[PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer. Not all embedded devices require it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require the block layer to be present. This patch does the following: (*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev support. (*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls an item that uses the block layer. This includes: (*) Block I/O tracing. (*) Disk partition code. (*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS. (*) The SCSI layer. As far as I can tell, even SCSI chardevs use the block layer to do scheduling. Some drivers that use SCSI facilities - such as USB storage - end up disabled indirectly from this. (*) Various block-based device drivers, such as IDE and the old CDROM drivers. (*) MTD blockdev handling and FTL. (*) JFFS - which uses set_bdev_super(), something it could avoid doing by taking a leaf out of JFFS2's book. (*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is, however, still used in places, and so is still available. (*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and parts of linux/fs.h. (*) Makes a number of files in fs/ contingent on CONFIG_BLOCK. (*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK. (*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK is not enabled. (*) fs/no-block.c is created to hold out-of-line stubs and things that are required when CONFIG_BLOCK is not set: (*) Default blockdev file operations (to give error ENODEV on opening). (*) Makes some /proc changes: (*) /proc/devices does not list any blockdevs. (*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK. (*) Makes some compat ioctl handling contingent on CONFIG_BLOCK. (*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if given command other than Q_SYNC or if a special device is specified. (*) In init/do_mounts.c, no reference is made to the blockdev routines if CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2. (*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return error ENOSYS by way of cond_syscall if so). (*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if CONFIG_BLOCK is not set, since they can't then happen. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/proc_misc.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index 5bbd60896050..66bc425f2f3d 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -277,12 +277,15 @@ static int devinfo_show(struct seq_file *f, void *v)
277 if (i == 0) 277 if (i == 0)
278 seq_printf(f, "Character devices:\n"); 278 seq_printf(f, "Character devices:\n");
279 chrdev_show(f, i); 279 chrdev_show(f, i);
280 } else { 280 }
281#ifdef CONFIG_BLOCK
282 else {
281 i -= CHRDEV_MAJOR_HASH_SIZE; 283 i -= CHRDEV_MAJOR_HASH_SIZE;
282 if (i == 0) 284 if (i == 0)
283 seq_printf(f, "\nBlock devices:\n"); 285 seq_printf(f, "\nBlock devices:\n");
284 blkdev_show(f, i); 286 blkdev_show(f, i);
285 } 287 }
288#endif
286 return 0; 289 return 0;
287} 290}
288 291
@@ -355,6 +358,7 @@ static int stram_read_proc(char *page, char **start, off_t off,
355} 358}
356#endif 359#endif
357 360
361#ifdef CONFIG_BLOCK
358extern struct seq_operations partitions_op; 362extern struct seq_operations partitions_op;
359static int partitions_open(struct inode *inode, struct file *file) 363static int partitions_open(struct inode *inode, struct file *file)
360{ 364{
@@ -378,6 +382,7 @@ static struct file_operations proc_diskstats_operations = {
378 .llseek = seq_lseek, 382 .llseek = seq_lseek,
379 .release = seq_release, 383 .release = seq_release,
380}; 384};
385#endif
381 386
382#ifdef CONFIG_MODULES 387#ifdef CONFIG_MODULES
383extern struct seq_operations modules_op; 388extern struct seq_operations modules_op;
@@ -695,7 +700,9 @@ void __init proc_misc_init(void)
695 entry->proc_fops = &proc_kmsg_operations; 700 entry->proc_fops = &proc_kmsg_operations;
696 create_seq_entry("devices", 0, &proc_devinfo_operations); 701 create_seq_entry("devices", 0, &proc_devinfo_operations);
697 create_seq_entry("cpuinfo", 0, &proc_cpuinfo_operations); 702 create_seq_entry("cpuinfo", 0, &proc_cpuinfo_operations);
703#ifdef CONFIG_BLOCK
698 create_seq_entry("partitions", 0, &proc_partitions_operations); 704 create_seq_entry("partitions", 0, &proc_partitions_operations);
705#endif
699 create_seq_entry("stat", 0, &proc_stat_operations); 706 create_seq_entry("stat", 0, &proc_stat_operations);
700 create_seq_entry("interrupts", 0, &proc_interrupts_operations); 707 create_seq_entry("interrupts", 0, &proc_interrupts_operations);
701#ifdef CONFIG_SLAB 708#ifdef CONFIG_SLAB
@@ -707,7 +714,9 @@ void __init proc_misc_init(void)
707 create_seq_entry("buddyinfo",S_IRUGO, &fragmentation_file_operations); 714 create_seq_entry("buddyinfo",S_IRUGO, &fragmentation_file_operations);
708 create_seq_entry("vmstat",S_IRUGO, &proc_vmstat_file_operations); 715 create_seq_entry("vmstat",S_IRUGO, &proc_vmstat_file_operations);
709 create_seq_entry("zoneinfo",S_IRUGO, &proc_zoneinfo_file_operations); 716 create_seq_entry("zoneinfo",S_IRUGO, &proc_zoneinfo_file_operations);
717#ifdef CONFIG_BLOCK
710 create_seq_entry("diskstats", 0, &proc_diskstats_operations); 718 create_seq_entry("diskstats", 0, &proc_diskstats_operations);
719#endif
711#ifdef CONFIG_MODULES 720#ifdef CONFIG_MODULES
712 create_seq_entry("modules", 0, &proc_modules_operations); 721 create_seq_entry("modules", 0, &proc_modules_operations);
713#endif 722#endif