[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>
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index b5382ce..422e31d 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -2,6 +2,8 @@
# Block device driver configuration
#
+if BLOCK
+
menu "Block devices"
config BLK_DEV_FD
@@ -468,3 +470,5 @@
devices like the Coraid EtherDrive (R) Storage Blade.
endmenu
+
+endif
diff --git a/drivers/cdrom/Kconfig b/drivers/cdrom/Kconfig
index ff5652d..4b12e90 100644
--- a/drivers/cdrom/Kconfig
+++ b/drivers/cdrom/Kconfig
@@ -3,7 +3,7 @@
#
menu "Old CD-ROM drivers (not SCSI, not IDE)"
- depends on ISA
+ depends on ISA && BLOCK
config CD_NO_IDESCSI
bool "Support non-SCSI/IDE/ATAPI CDROM drives"
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 4cc619e..bde1c66 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -1006,6 +1006,7 @@
config RAW_DRIVER
tristate "RAW driver (/dev/raw/rawN) (OBSOLETE)"
+ depends on BLOCK
help
The raw driver permits block devices to be bound to /dev/raw/rawN.
Once bound, I/O against /dev/raw/rawN uses efficient zero-copy I/O.
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 4c3a5ca..b430a12 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -655,6 +655,7 @@
add_timer_randomness(irq_timer_state[irq], 0x100 + irq);
}
+#ifdef CONFIG_BLOCK
void add_disk_randomness(struct gendisk *disk)
{
if (!disk || !disk->random)
@@ -667,6 +668,7 @@
}
EXPORT_SYMBOL(add_disk_randomness);
+#endif
#define EXTRACT_SIZE 10
@@ -918,6 +920,7 @@
}
}
+#ifdef CONFIG_BLOCK
void rand_initialize_disk(struct gendisk *disk)
{
struct timer_rand_state *state;
@@ -932,6 +935,7 @@
disk->random = state;
}
}
+#endif
static ssize_t
random_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
diff --git a/drivers/ide/Kconfig b/drivers/ide/Kconfig
index b6fb167..69d627b 100644
--- a/drivers/ide/Kconfig
+++ b/drivers/ide/Kconfig
@@ -4,6 +4,8 @@
# Andre Hedrick <andre@linux-ide.org>
#
+if BLOCK
+
menu "ATA/ATAPI/MFM/RLL support"
config IDE
@@ -1082,3 +1084,5 @@
endif
endmenu
+
+endif
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index bf869ed..6dd31a2 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -2,6 +2,8 @@
# Block device driver configuration
#
+if BLOCK
+
menu "Multi-device support (RAID and LVM)"
config MD
@@ -251,3 +253,4 @@
endmenu
+endif
diff --git a/drivers/message/i2o/Kconfig b/drivers/message/i2o/Kconfig
index fef6771..6443392 100644
--- a/drivers/message/i2o/Kconfig
+++ b/drivers/message/i2o/Kconfig
@@ -88,7 +88,7 @@
config I2O_BLOCK
tristate "I2O Block OSM"
- depends on I2O
+ depends on I2O && BLOCK
---help---
Include support for the I2O Block OSM. The Block OSM presents disk
and other structured block devices to the operating system. If you
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 45bcf09..f540bd8 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -21,7 +21,7 @@
config MMC_BLOCK
tristate "MMC block device driver"
- depends on MMC
+ depends on MMC && BLOCK
default y
help
Say Y here to enable the MMC block device driver support.
diff --git a/drivers/mmc/Makefile b/drivers/mmc/Makefile
index d2957e3..b1f6e03 100644
--- a/drivers/mmc/Makefile
+++ b/drivers/mmc/Makefile
@@ -24,7 +24,8 @@
obj-$(CONFIG_MMC_OMAP) += omap.o
obj-$(CONFIG_MMC_AT91RM9200) += at91_mci.o
-mmc_core-y := mmc.o mmc_queue.o mmc_sysfs.o
+mmc_core-y := mmc.o mmc_sysfs.o
+mmc_core-$(CONFIG_BLOCK) += mmc_queue.o
ifeq ($(CONFIG_MMC_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index a03e862..a304b34 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -166,7 +166,7 @@
config MTD_BLOCK
tristate "Caching block device access to MTD devices"
- depends on MTD
+ depends on MTD && BLOCK
---help---
Although most flash chips have an erase size too large to be useful
as block devices, it is possible to use MTD devices which are based
@@ -188,7 +188,7 @@
config MTD_BLOCK_RO
tristate "Readonly block device access to MTD devices"
- depends on MTD_BLOCK!=y && MTD
+ depends on MTD_BLOCK!=y && MTD && BLOCK
help
This allows you to mount read-only file systems (such as cramfs)
from an MTD device, without the overhead (and danger) of the caching
@@ -199,7 +199,7 @@
config FTL
tristate "FTL (Flash Translation Layer) support"
- depends on MTD
+ depends on MTD && BLOCK
---help---
This provides support for the original Flash Translation Layer which
is part of the PCMCIA specification. It uses a kind of pseudo-
@@ -215,7 +215,7 @@
config NFTL
tristate "NFTL (NAND Flash Translation Layer) support"
- depends on MTD
+ depends on MTD && BLOCK
---help---
This provides support for the NAND Flash Translation Layer which is
used on M-Systems' DiskOnChip devices. It uses a kind of pseudo-
@@ -238,7 +238,7 @@
config INFTL
tristate "INFTL (Inverse NAND Flash Translation Layer) support"
- depends on MTD
+ depends on MTD && BLOCK
---help---
This provides support for the Inverse NAND Flash Translation
Layer which is used on M-Systems' newer DiskOnChip devices. It
@@ -255,7 +255,7 @@
config RFD_FTL
tristate "Resident Flash Disk (Flash Translation Layer) support"
- depends on MTD
+ depends on MTD && BLOCK
---help---
This provides support for the flash translation layer known
as the Resident Flash Disk (RFD), as used by the Embedded BIOS
diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index 16c02b5..440f685 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/drivers/mtd/devices/Kconfig
@@ -136,7 +136,7 @@
config MTD_BLOCK2MTD
tristate "MTD using block device"
- depends on MTD
+ depends on MTD && BLOCK
help
This driver allows a block device to appear as an MTD. It would
generally be used in the following cases:
diff --git a/drivers/s390/block/Kconfig b/drivers/s390/block/Kconfig
index 929d6ff..b250c53 100644
--- a/drivers/s390/block/Kconfig
+++ b/drivers/s390/block/Kconfig
@@ -1,4 +1,4 @@
-if S390
+if S390 && BLOCK
comment "S/390 block device drivers"
depends on S390
diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index c4dfcc9..dab0820 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -3,11 +3,13 @@
config RAID_ATTRS
tristate "RAID Transport Class"
default n
+ depends on BLOCK
---help---
Provides RAID
config SCSI
tristate "SCSI device support"
+ depends on BLOCK
---help---
If you want to use a SCSI hard disk, SCSI tape drive, SCSI CD-ROM or
any other SCSI device under Linux, say Y and make sure that you know