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authorMinchan Kim <minchan@kernel.org>2017-11-15 17:33:00 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-15 18:21:02 -0800
commit23c47d2ada9f96731492a67b28c0072715075baa (patch)
treedbe8a9322eab448997e27b19b1b39b235eaddd2a /drivers/block/brd.c
parente447a0151f7ce8dd884fea48279274bd64434c29 (diff)
bdi: introduce BDI_CAP_SYNCHRONOUS_IO
As discussed at https://lkml.kernel.org/r/<20170728165604.10455-1-ross.zwisler@linux.intel.com> someday we will remove rw_page(). If so, we need something to detect such super-fast storage on which synchronous IO operations like the current rw_page are always a win. Introduces BDI_CAP_SYNCHRONOUS_IO to indicate such devices. With it, we could use various optimization techniques. Link: http://lkml.kernel.org/r/1505886205-9671-3-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/block/brd.c')
-rw-r--r--drivers/block/brd.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index c1cf87718c2e..588360d79fca 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -20,6 +20,7 @@
#include <linux/radix-tree.h>
#include <linux/fs.h>
#include <linux/slab.h>
+#include <linux/backing-dev.h>
#ifdef CONFIG_BLK_DEV_RAM_DAX
#include <linux/pfn_t.h>
#include <linux/dax.h>
@@ -448,6 +449,7 @@ static struct brd_device *brd_alloc(int i)
disk->flags = GENHD_FL_EXT_DEVT;
sprintf(disk->disk_name, "ram%d", i);
set_capacity(disk, rd_size * 2);
+ disk->queue->backing_dev_info->capabilities |= BDI_CAP_SYNCHRONOUS_IO;
#ifdef CONFIG_BLK_DEV_RAM_DAX
queue_flag_set_unlocked(QUEUE_FLAG_DAX, brd->brd_queue);

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