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block: remove CONFIG_DEBUG_BLOCK_EXT_DEVT

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This might have been a neat debug aid when the extended dev_t was
added, but that time is long gone.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210824075216.1179406-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2021-08-24 09:52:16 +02:00 committed by Jens Axboe
parent 539711d7d6
commit c4b2b7d150
5 changed files with 4 additions and 72 deletions
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1
arch/riscv/configs/defconfig
View File

@ -132,7 +132,6 @@ CONFIG_DEBUG_PLIST=y
CONFIG_DEBUG_SG=y
# CONFIG_RCU_TRACE is not set
CONFIG_RCU_EQS_DEBUG=y
CONFIG_DEBUG_BLOCK_EXT_DEVT=y
# CONFIG_FTRACE is not set
# CONFIG_RUNTIME_TESTING_MENU is not set
CONFIG_MEMTEST=y

1
arch/riscv/configs/rv32_defconfig
View File

@ -127,7 +127,6 @@ CONFIG_DEBUG_PLIST=y
CONFIG_DEBUG_SG=y
# CONFIG_RCU_TRACE is not set
CONFIG_RCU_EQS_DEBUG=y
CONFIG_DEBUG_BLOCK_EXT_DEVT=y
# CONFIG_FTRACE is not set
# CONFIG_RUNTIME_TESTING_MENU is not set
CONFIG_MEMTEST=y

43
block/genhd.c
View File

@ -313,54 +313,19 @@ void unregister_blkdev(unsigned int major, const char *name)
EXPORT_SYMBOL(unregister_blkdev);
/**
* blk_mangle_minor - scatter minor numbers apart
* @minor: minor number to mangle
*
* Scatter consecutively allocated @minor number apart if MANGLE_DEVT
* is enabled. Mangling twice gives the original value.
*
* RETURNS:
* Mangled value.
*
* CONTEXT:
* Don't care.
*/
static int blk_mangle_minor(int minor)
{
#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
int i;
for (i = 0; i < MINORBITS / 2; i++) {
int low = minor & (1 << i);
int high = minor & (1 << (MINORBITS - 1 - i));
int distance = MINORBITS - 1 - 2 * i;
minor ^= low | high; /* clear both bits */
low <<= distance; /* swap the positions */
high >>= distance;
minor |= low | high; /* and set */
}
#endif
return minor;
}
int blk_alloc_ext_minor(void)
{
int idx;
idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT, GFP_KERNEL);
if (idx < 0) {
if (idx == -ENOSPC)
return -EBUSY;
return idx;
}
return blk_mangle_minor(idx);
if (idx == -ENOSPC)
return -EBUSY;
return idx;
}
void blk_free_ext_minor(unsigned int minor)
{
ida_free(&ext_devt_ida, blk_mangle_minor(minor));
ida_free(&ext_devt_ida, minor);
}
static char *bdevt_str(dev_t devt, char *buf)

4
init/do_mounts.c
View File

@ -432,10 +432,6 @@ retry:
printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
printk_all_partitions();
#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
"explicit textual name for \"root=\" boot option.\n");
#endif
panic("VFS: Unable to mount root fs on %s", b);
}
if (!(flags & SB_RDONLY)) {

27
lib/Kconfig.debug
View File

@ -1679,33 +1679,6 @@ config DEBUG_WQ_FORCE_RR_CPU
feature by default. When enabled, memory and cache locality will
be impacted.
config DEBUG_BLOCK_EXT_DEVT
bool "Force extended block device numbers and spread them"
depends on DEBUG_KERNEL
depends on BLOCK
default n
help
BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
YOU ARE DOING. Distros, please enable this and fix whatever
is broken.
Conventionally, block device numbers are allocated from
predetermined contiguous area. However, extended block area
may introduce non-contiguous block device numbers. This
option forces most block device numbers to be allocated from
the extended space and spreads them to discover kernel or
userland code paths which assume predetermined contiguous
device number allocation.
Note that turning on this debug option shuffles all the
device numbers for all IDE and SCSI devices including libata
ones, so root partition specified using device number
directly (via rdev or root=MAJ:MIN) won't work anymore.
Textual device names (root=/dev/sdXn) will continue to work.
Say N if you are unsure.
config CPU_HOTPLUG_STATE_CONTROL
bool "Enable CPU hotplug state control"
depends on DEBUG_KERNEL