From 9361401eb7619c033e2394e4f9f6d410d6719ac7 Mon Sep 17 00:00:00 2001 From: David Howells Date: Sat, 30 Sep 2006 20:45:40 +0200 Subject: [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 Signed-off-by: Jens Axboe --- drivers/block/Kconfig | 4 ++++ drivers/cdrom/Kconfig | 2 +- drivers/char/Kconfig | 1 + drivers/char/random.c | 4 ++++ drivers/ide/Kconfig | 4 ++++ drivers/md/Kconfig | 3 +++ drivers/message/i2o/Kconfig | 2 +- drivers/mmc/Kconfig | 2 +- drivers/mmc/Makefile | 3 ++- drivers/mtd/Kconfig | 12 ++++++------ drivers/mtd/devices/Kconfig | 2 +- drivers/s390/block/Kconfig | 2 +- drivers/scsi/Kconfig | 2 ++ 13 files changed, 31 insertions(+), 12 deletions(-) (limited to 'drivers') diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index b5382cedf0c..422e31d5f8e 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 @@ config ATA_OVER_ETH devices like the Coraid EtherDrive (R) Storage Blade. endmenu + +endif diff --git a/drivers/cdrom/Kconfig b/drivers/cdrom/Kconfig index ff5652d4061..4b12e9031fb 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 4cc619edf42..bde1c665d9f 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -1006,6 +1006,7 @@ config GPIO_VR41XX 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 4c3a5ca9d8f..b430a12eb81 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -655,6 +655,7 @@ void add_interrupt_randomness(int irq) 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 @@ void add_disk_randomness(struct gendisk *disk) } EXPORT_SYMBOL(add_disk_randomness); +#endif #define EXTRACT_SIZE 10 @@ -918,6 +920,7 @@ void rand_initialize_irq(int irq) } } +#ifdef CONFIG_BLOCK void rand_initialize_disk(struct gendisk *disk) { struct timer_rand_state *state; @@ -932,6 +935,7 @@ void rand_initialize_disk(struct gendisk *disk) 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 b6fb167e20f..69d627bd537 100644 --- a/drivers/ide/Kconfig +++ b/drivers/ide/Kconfig @@ -4,6 +4,8 @@ # Andre Hedrick # +if BLOCK + menu "ATA/ATAPI/MFM/RLL support" config IDE @@ -1082,3 +1084,5 @@ config BLK_DEV_HD endif endmenu + +endif diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index bf869ed03ee..6dd31a291d8 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 @@ config DM_MULTIPATH_EMC endmenu +endif diff --git a/drivers/message/i2o/Kconfig b/drivers/message/i2o/Kconfig index fef67710388..6443392bfff 100644 --- a/drivers/message/i2o/Kconfig +++ b/drivers/message/i2o/Kconfig @@ -88,7 +88,7 @@ config I2O_BUS 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 45bcf098e76..f540bd88dc5 100644 --- a/drivers/mmc/Kconfig +++ b/drivers/mmc/Kconfig @@ -21,7 +21,7 @@ config MMC_DEBUG 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 d2957e35cc6..b1f6e03e7aa 100644 --- a/drivers/mmc/Makefile +++ b/drivers/mmc/Makefile @@ -24,7 +24,8 @@ obj-$(CONFIG_MMC_AU1X) += au1xmmc.o obj-$(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 a03e862851d..a304b34c263 100644 --- a/drivers/mtd/Kconfig +++ b/drivers/mtd/Kconfig @@ -166,7 +166,7 @@ config MTD_CHAR 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 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 MTD_BLOCK_RO 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 FTL 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 NFTL_RW 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 INFTL 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 16c02b5ccf7..440f6851da6 100644 --- a/drivers/mtd/devices/Kconfig +++ b/drivers/mtd/devices/Kconfig @@ -136,7 +136,7 @@ config MTDRAM_ABS_POS 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 929d6fff615..b250c535450 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 c4dfcc91ddd..dab082002e6 100644 --- a/drivers/scsi/Kconfig +++ b/drivers/scsi/Kconfig @@ -3,11 +3,13 @@ menu "SCSI device support" 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 -- cgit v1.2.3