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authorMikulas Patocka <mpatocka@redhat.com>2017-09-01 04:47:43 +0300
committerMike Snitzer <snitzer@redhat.com>2017-09-11 18:00:55 +0300
commitc3ca015fab6df124c933b91902f3f2a3473f9da5 (patch)
treea43633630e05a08bbb14de927b4d399b5d2f6c1d /drivers/md/dm-stripe.c
parentb5e8ad92c3ac0b073bbf08ffd1a6a31d3449caae (diff)
downloadlinux-c3ca015fab6df124c933b91902f3f2a3473f9da5.tar.xz
dax: remove the pmem_dax_ops->flush abstraction
Commit abebfbe2f731 ("dm: add ->flush() dax operation support") is buggy. A DM device may be composed of multiple underlying devices and all of them need to be flushed. That commit just routes the flush request to the first device and ignores the other devices. It could be fixed by adding more complex logic to the device mapper. But there is only one implementation of the method pmem_dax_ops->flush - that is pmem_dax_flush() - and it calls arch_wb_cache_pmem(). Consequently, we don't need the pmem_dax_ops->flush abstraction at all, we can call arch_wb_cache_pmem() directly from dax_flush() because dax_dev->ops->flush can't ever reach anything different from arch_wb_cache_pmem(). It should be also pointed out that for some uses of persistent memory it is needed to flush only a very small amount of data (such as 1 cacheline), and it would be overkill if we go through that device mapper machinery for a single flushed cache line. Fix this by removing the pmem_dax_ops->flush abstraction and call arch_wb_cache_pmem() directly from dax_flush(). Also, remove the device mapper code that forwards the flushes. Fixes: abebfbe2f731 ("dm: add ->flush() dax operation support") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-stripe.c')
-rw-r--r--drivers/md/dm-stripe.c20
1 files changed, 0 insertions, 20 deletions
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index a0375530b07f..1690bb299b3f 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -351,25 +351,6 @@ static size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
}
-static void stripe_dax_flush(struct dm_target *ti, pgoff_t pgoff, void *addr,
- size_t size)
-{
- sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
- struct stripe_c *sc = ti->private;
- struct dax_device *dax_dev;
- struct block_device *bdev;
- uint32_t stripe;
-
- stripe_map_sector(sc, sector, &stripe, &dev_sector);
- dev_sector += sc->stripe[stripe].physical_start;
- dax_dev = sc->stripe[stripe].dev->dax_dev;
- bdev = sc->stripe[stripe].dev->bdev;
-
- if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(size, PAGE_SIZE), &pgoff))
- return;
- dax_flush(dax_dev, pgoff, addr, size);
-}
-
/*
* Stripe status:
*
@@ -491,7 +472,6 @@ static struct target_type stripe_target = {
.io_hints = stripe_io_hints,
.direct_access = stripe_dax_direct_access,
.dax_copy_from_iter = stripe_dax_copy_from_iter,
- .dax_flush = stripe_dax_flush,
};
int __init dm_stripe_init(void)