diff options
Diffstat (limited to 'Documentation/block')
| -rw-r--r-- | Documentation/block/cmdline-partition.txt | 21 | ||||
| -rw-r--r-- | Documentation/block/null_blk.txt | 9 |
2 files changed, 20 insertions, 10 deletions
diff --git a/Documentation/block/cmdline-partition.txt b/Documentation/block/cmdline-partition.txt index 525b9f6d7fb4..760a3f7c3ed4 100644 --- a/Documentation/block/cmdline-partition.txt +++ b/Documentation/block/cmdline-partition.txt @@ -1,7 +1,9 @@ Embedded device command line partition parsing ===================================================================== -Support for reading the block device partition table from the command line. +The "blkdevparts" command line option adds support for reading the +block device partition table from the kernel command line. + It is typically used for fixed block (eMMC) embedded devices. It has no MBR, so saves storage space. Bootloader can be easily accessed by absolute address of data on the block device. @@ -14,22 +16,27 @@ blkdevparts=<blkdev-def>[;<blkdev-def>] <partdef> := <size>[@<offset>](part-name) <blkdev-id> - block device disk name, embedded device used fixed block device, - it's disk name also fixed. such as: mmcblk0, mmcblk1, mmcblk0boot0. + block device disk name. Embedded device uses fixed block device. + Its disk name is also fixed, such as: mmcblk0, mmcblk1, mmcblk0boot0. <size> partition size, in bytes, such as: 512, 1m, 1G. + size may contain an optional suffix of (upper or lower case): + K, M, G, T, P, E. + "-" is used to denote all remaining space. <offset> partition start address, in bytes. + offset may contain an optional suffix of (upper or lower case): + K, M, G, T, P, E. (part-name) - partition name, kernel send uevent with "PARTNAME". application can create - a link to block device partition with the name "PARTNAME". - user space application can access partition by partition name. + partition name. Kernel sends uevent with "PARTNAME". Application can + create a link to block device partition with the name "PARTNAME". + User space application can access partition by partition name. Example: - eMMC disk name is "mmcblk0" and "mmcblk0boot0" + eMMC disk names are "mmcblk0" and "mmcblk0boot0". bootargs: 'blkdevparts=mmcblk0:1G(data0),1G(data1),-;mmcblk0boot0:1m(boot),-(kernel)' diff --git a/Documentation/block/null_blk.txt b/Documentation/block/null_blk.txt index 733927a7b501..07f147381f32 100644 --- a/Documentation/block/null_blk.txt +++ b/Documentation/block/null_blk.txt @@ -71,13 +71,16 @@ use_per_node_hctx=[0/1]: Default: 0 1: The multi-queue block layer is instantiated with a hardware dispatch queue for each CPU node in the system. -use_lightnvm=[0/1]: Default: 0 - Register device with LightNVM. Requires blk-mq and CONFIG_NVM to be enabled. - no_sched=[0/1]: Default: 0 0: nullb* use default blk-mq io scheduler. 1: nullb* doesn't use io scheduler. +blocking=[0/1]: Default: 0 + 0: Register as a non-blocking blk-mq driver device. + 1: Register as a blocking blk-mq driver device, null_blk will set + the BLK_MQ_F_BLOCKING flag, indicating that it sometimes/always + needs to block in its ->queue_rq() function. + shared_tags=[0/1]: Default: 0 0: Tag set is not shared. 1: Tag set shared between devices for blk-mq. Only makes sense with |