user/sven/linux.git/drivers/block/brd.c, branch v5.15.138

brd: mark as nowait compatible

2023-03-17T07:48:51Z

[ Upstream commit 67205f80be9910207481406c47f7d85e703fb2e9 ] By default, non-mq drivers do not support nowait. This causes io_uring to use a slower path as the driver cannot be trust not to block. brd can safely set the nowait flag, as worst case all it does is a NOIO allocation. For io_uring, this makes a substantial difference. Before: submitter=0, tid=453, file=/dev/ram0, node=-1 polled=0, fixedbufs=1/0, register_files=1, buffered=0, QD=128 Engine=io_uring, sq_ring=128, cq_ring=128 IOPS=440.03K, BW=1718MiB/s, IOS/call=32/31 IOPS=428.96K, BW=1675MiB/s, IOS/call=32/32 IOPS=442.59K, BW=1728MiB/s, IOS/call=32/31 IOPS=419.65K, BW=1639MiB/s, IOS/call=32/32 IOPS=426.82K, BW=1667MiB/s, IOS/call=32/31 and after: submitter=0, tid=354, file=/dev/ram0, node=-1 polled=0, fixedbufs=1/0, register_files=1, buffered=0, QD=128 Engine=io_uring, sq_ring=128, cq_ring=128 IOPS=3.37M, BW=13.15GiB/s, IOS/call=32/31 IOPS=3.45M, BW=13.46GiB/s, IOS/call=32/31 IOPS=3.43M, BW=13.42GiB/s, IOS/call=32/32 IOPS=3.43M, BW=13.39GiB/s, IOS/call=32/31 IOPS=3.43M, BW=13.38GiB/s, IOS/call=32/31 or about an 8x in difference. Now that brd is prepared to deal with REQ_NOWAIT reads/writes, mark it as supporting that. Cc: stable@vger.kernel.org # 5.10+ Link: https://lore.kernel.org/linux-block/20230203103005.31290-1-p.raghav@samsung.com/ Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block/brd: add error handling support for add_disk()

2023-03-17T07:48:51Z

[ Upstream commit e1528830bd4ebf435d91c154e309e6e028336210 ] We never checked for errors on add_disk() as this function returned void. Now that this is fixed, use the shiny new error handling. Signed-off-by: Luis Chamberlain Link: https://lore.kernel.org/r/20211015235219.2191207-2-mcgrof@kernel.org Signed-off-by: Jens Axboe Stable-dep-of: 67205f80be99 ("brd: mark as nowait compatible") Signed-off-by: Sasha Levin

brd: return 0/-error from brd_insert_page()

2023-03-10T08:40:02Z

commit db0ccc44a20b4bb3039c0f6885a1f9c3323c7673 upstream. It currently returns a page, but callers just check for NULL/page to gauge success. Clean this up and return the appropriate error directly instead. Cc: stable@vger.kernel.org # 5.10+ Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

brd: reduce the brd_devices_mutex scope

2021-10-17T12:51:19Z

As with commit 8b52d8be86d72308 ("loop: reorder loop_exit"), unregister_blkdev() needs to be called first in order to avoid calling brd_alloc() from brd_probe() after brd_del_one() from brd_exit(). Then, we can avoid holding global mutex during add_disk()/del_gendisk() as with commit 1c500ad706383f1a ("loop: reduce the loop_ctl_mutex scope"). Signed-off-by: Tetsuo Handa Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/e205f13d-18ff-a49c-0988-7de6ea5ff823@i-love.sakura.ne.jp Signed-off-by: Jens Axboe

block: move some macros to blkdev.h

2021-08-12T01:40:28Z

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

2021-06-01T13:42:23Z

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

2021-05-07T02:24:11Z

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

2021-04-21T16:54:48Z

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

2021-01-25T01:17:20Z

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

2021-01-25T01:17:20Z

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