linux-toradex.git/drivers/block/brd.c, branch v5.15-rc3

block: move some macros to blkdev.h

2021-08-12T01:40:28+00:00

Move them (PAGE_SECTORS_SHIFT, PAGE_SECTORS and SECTOR_MASK) to the
generic header file to remove redundancy.

Signed-off-by: Guoqing Jiang 
Link: https://lore.kernel.org/r/20210721025315.1729118-1-guoqing.jiang@linux.dev
Signed-off-by: Jens Axboe

brd: convert to blk_alloc_disk/blk_cleanup_disk

2021-06-01T13:42:23+00:00

Convert the brd driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation.  This also
allows to remove the request_queue pointer in struct request_queue,
and to simplify the initialization as blk_cleanup_disk can be called
on any disk returned from blk_alloc_disk.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Ulf Hansson 
Link: https://lore.kernel.org/r/20210521055116.1053587-7-hch@lst.de
Signed-off-by: Jens Axboe

include: remove pagemap.h from blkdev.h

2021-05-07T02:24:11+00:00

My UEK-derived config has 1030 files depending on pagemap.h before this
change.  Afterwards, just 326 files need to be rebuilt when I touch
pagemap.h.  I think blkdev.h is probably included too widely, but
untangling that dependency is harder and this solves my problem.  x86
allmodconfig builds, but there may be implicit include problems on other
architectures.

Link: https://lkml.kernel.org/r/20210309195747.283796-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Acked-by: Dan Williams 		[nvdimm]
Acked-by: Jens Axboe 				[block]
Reviewed-by: Christoph Hellwig 
Acked-by: Coly Li 				[bcache]
Acked-by: Martin K. Petersen 	[scsi]
Reviewed-by: William Kucharski 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

brd: expose number of allocated pages in debugfs

2021-04-21T16:54:48+00:00

While the maximum size of each ramdisk is defined either as a module
parameter, or compile time default, it's impossible to know how many pages
have currently been allocated by each ram%d device, since they're
allocated when used and never freed.

This patch creates a new directory at this location:

/sys/kernel/debug/ramdisk_pages/

which will contain a file named "ram%d" for each instantiated ramdisk on
the system. The file is read-only, and read() will output the number of
pages currently held by that ramdisk.

We lose track how much memory a ramdisk is using as pages once used are
simply recycled but never freed.

In instances where we exhaust the size of the ramdisk with a file that
exceeds it, encounter ENOSPC and delete the file for mitigation; df would
show decrease in used and increase in available blocks but the since we
have touched all pages, the memory footprint of the ramdisk does not
reflect the blocks used/available count

...
[root@localhost ~]# mkfs.ext2 /dev/ram15
mke2fs 1.45.6 (20-Mar-2020)
Creating filesystem with 4096 1k blocks and 1024 inodes
[root@localhost ~]# mount /dev/ram15 /mnt/ram15/

[root@localhost ~]# cat
/sys/kernel/debug/ramdisk_pages/ram15
58
[root@kerneltest008.06.prn3 ~]# df /dev/ram15
Filesystem     1K-blocks  Used Available Use% Mounted on
/dev/ram15          3963    31      3728   1% /mnt/ram15
[root@kerneltest008.06.prn3 ~]# dd if=/dev/urandom of=/mnt/ram15/test2
bs=1M count=5
dd: error writing '/mnt/ram15/test2': No space left on device
4+0 records in
3+0 records out
4005888 bytes (4.0 MB, 3.8 MiB) copied, 0.0446614 s, 89.7 MB/s
[root@kerneltest008.06.prn3 ~]# df /mnt/ram15/
Filesystem     1K-blocks  Used Available Use% Mounted on
/dev/ram15          3963  3960         0 100% /mnt/ram15
[root@kerneltest008.06.prn3 ~]# cat
/sys/kernel/debug/ramdisk_pages/ram15
1024
[root@kerneltest008.06.prn3 ~]# rm /mnt/ram15/test2
rm: remove regular file '/mnt/ram15/test2'? y
[root@kerneltest008.06.prn3 /var]# df /dev/ram15
Filesystem     1K-blocks  Used Available Use% Mounted on
/dev/ram15          3963    31      3728   1% /mnt/ram15

# Acutal memory footprint
[root@kerneltest008.06.prn3 /var]# cat
/sys/kernel/debug/ramdisk_pages/ram15
1024
...

This debugfs counter will always reveal the accurate number of
permanently allocated pages to the ramdisk.

Signed-off-by: Calvin Owens 
[cleaned up the !CONFIG_DEBUG_FS case and API changes for HEAD]
Signed-off-by: Kyle McMartin 
[rebased]
Signed-off-by: Saravanan D 
Signed-off-by: Jens Axboe

block: store a block_device pointer in struct bio

2021-01-25T01:17:20+00:00

Replace the gendisk pointer in struct bio with a pointer to the newly
improved struct block device.  From that the gendisk can be trivially
accessed with an extra indirection, but it also allows to directly
look up all information related to partition remapping.

Signed-off-by: Christoph Hellwig 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe

brd: remove the end of device check in brd_do_bvec

2021-01-25T01:17:20+00:00

The block layer already checks for this conditions in bio_check_eod
before calling the driver.

Signed-off-by: Christoph Hellwig 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe

brd: use __register_blkdev to allocate devices on demand

2020-11-16T15:14:30+00:00

Use the simpler mechanism attached to major_name to allocate a brd device
when a currently unregistered minor is accessed.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Jens Axboe

bdi: remove BDI_CAP_SYNCHRONOUS_IO

2020-09-24T19:43:39+00:00

BDI_CAP_SYNCHRONOUS_IO is only checked in the swap code, and used to
decided if ->rw_page can be used on a block device.  Just check up for
the method instead.  The only complication is that zram needs a second
set of block_device_operations as it can switch between modes that
actually support ->rw_page and those who don't.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Reviewed-by: Johannes Thumshirn 
Signed-off-by: Jens Axboe

block: move ->make_request_fn to struct block_device_operations

2020-07-01T13:27:24+00:00

The make_request_fn is a little weird in that it sits directly in
struct request_queue instead of an operation vector.  Replace it with
a block_device_operations method called submit_bio (which describes much
better what it does).  Also remove the request_queue argument to it, as
the queue can be derived pretty trivially from the bio.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: simplify queue allocation

2020-03-27T16:23:43+00:00

Current make_request based drivers use either blk_alloc_queue_node or
blk_alloc_queue to allocate a queue, and then set up the make_request_fn
function pointer and a few parameters using the blk_queue_make_request
helper.  Simplify this by passing the make_request pointer to
blk_alloc_queue, and while at it merge the _node variant into the main
helper by always passing a node_id, and remove the superfluous gfp_mask
parameter.  A lower-level __blk_alloc_queue is kept for the blk-mq case.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe