dm,dax: Make sure dm_dax_flush() is called if device supports it
Subsystems (4)
PATCH 1/1 dm,dax: Make sure dm_dax_flush() is called if device supports it
Right now, dm_dax_flush() is not being called and I think it is not being called becuase DAXDEV_WRITE_CACHE is not set on dm dax device.
If underlying dax device supports write cache, set DAXDEV_WRITE_CACHE on dm dax device. This will get dm_dax_flush() being called.
--- drivers/dax/super.c | 5 +++++ drivers/md/dm-table.c | 33 +++++++++++++++++++++++++++++++++ include/linux/dax.h | 1 + 3 files changed, 39 insertions(+)
drivers/dax/super.c +5 -0
@@ -278,6 +278,11 @@ void dax_write_cache(struct dax_device *dax_dev, bool wc) }EXPORT_SYMBOL_GPL (dax_write_cache); +bool dax_write_cache_enabled (struct dax_device *dax_dev) +{ +return test_bit (DAXDEV_WRITE_CACHE , &dax_dev->flags); +} +bool dax_alive (struct dax_device *dax_dev) {lockdep_assert_held (&dax_srcu);
drivers/md/dm-table.c +33 -0
@@ -20,6 +20,7 @@#include <linux/atomic.h> #include <linux/blk-mq.h> #include <linux/mount.h> +#include <linux/dax.h> #define DM_MSG_PREFIX "table"
@@ -1630,6 +1631,35 @@ static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)return false; } +static int device_dax_flush_capable (struct dm_target *ti,struct dm_dev *dev, +sector_t start,sector_t len,void *data) +{ +struct dax_device *dax_dev = dev->dax_dev; + +if (!dax_dev) +return false; + +if (dax_write_cache_enabled (dax_dev)) +return true; +return false; +} + +static int dm_table_supports_dax_flush (struct dm_table *t) +{ +struct dm_target *ti; +unsigned i; + +for (i =0 ; i <dm_table_get_num_targets (t); i++) { + ti =dm_table_get_target (t, i); + +if (ti->type->iterate_devices && + ti->type->iterate_devices (ti, device_dax_flush_capable,NULL )) +return true; + } + +return false; +} +static int device_is_nonrot (struct dm_target *ti,struct dm_dev *dev,sector_t start,sector_t len,void *data) {
@@ -1785,6 +1815,9 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, }blk_queue_write_cache (q, wc, fua); +if (dm_table_supports_dax_flush (t)) +dax_write_cache (t->md->dax_dev, true); +/* Ensure that all underlying devices are non-rotational. */ if (dm_table_all_devices_attribute (t, device_is_nonrot))queue_flag_set_unlocked (QUEUE_FLAG_NONROT , q);
include/linux/dax.h +1 -0
@@ -87,6 +87,7 @@ size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,void dax_flush (struct dax_device *dax_dev,pgoff_t pgoff,void *addr,size_t size);void dax_write_cache (struct dax_device *dax_dev,bool wc); +bool dax_write_cache_enabled (struct dax_device *dax_dev);/* * We use lowest available bit in exceptional entry for locking, one bit for
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Dan Williams
Acked-byQuoted 18 lines · Vivek Goyal
Right now,
dm_dax_flush()is not being called and I think it is not being called becuaseDAXDEV_WRITE_CACHEis not set on dm dax device.If underlying dax device supports write cache, set
DAXDEV_WRITE_CACHEon dm dax device. This will getdm_dax_flush()being called.Signed-off-by Vivek Goyal <[email protected]>--- drivers/dax/super.c | 5 +++++ drivers/md/dm-table.c | 33 +++++++++++++++++++++++++++++++++ include/linux/dax.h | 1 + 3 files changed, 39 insertions(+)drivers/dax/super.c +0
-0
drivers/dax/super.c void dax_write_cache(struct dax_device *dax_dev, bool wc) · line 284
Quoted 7 lines
drivers/dax/super.c +4
-0@@ -278,6 +278,11 @@ void dax_write_cache(struct dax_device *dax_dev, bool wc) }EXPORT_SYMBOL_GPL (dax_write_cache); +bool dax_write_cache_enabled (struct dax_device *dax_dev) +{ +return test_bit (DAXDEV_WRITE_CACHE , &dax_dev->flags); +}
We need :
EXPORT_SYMBOL_GPL(dax_write_cache_enabled)
...but other than that, looks good to me.
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Re: [PATCH] dm, dax: Make sure dm_dax_flush() is called if device supports it
Quoted 29 lines · Dan Williams
Quoted 18 lines · Vivek Goyal
Right now,
dm_dax_flush()is not being called and I think it is not being called becuaseDAXDEV_WRITE_CACHEis not set on dm dax device.If underlying dax device supports write cache, set
DAXDEV_WRITE_CACHEon dm dax device. This will getdm_dax_flush()being called.Signed-off-by Vivek Goyal <[email protected]>--- drivers/dax/super.c | 5 +++++ drivers/md/dm-table.c | 33 +++++++++++++++++++++++++++++++++ include/linux/dax.h | 1 + 3 files changed, 39 insertions(+)drivers/dax/super.c +0
-0drivers/dax/super.c void dax_write_cache(struct dax_device *dax_dev, bool wc) · line 284
Quoted 7 lines
drivers/dax/super.c +4
-0@@ -278,6 +278,11 @@ void dax_write_cache(struct dax_device *dax_dev, bool wc) }EXPORT_SYMBOL_GPL (dax_write_cache); +bool dax_write_cache_enabled (struct dax_device *dax_dev) +{ +return test_bit (DAXDEV_WRITE_CACHE , &dax_dev->flags); +}We need :
Quoted 3 lines
EXPORT_SYMBOL_GPL(dax_write_cache_enabled)...but other than that, looks good to me.
Aha, missed that. Will fix in next version.
Vivek
Quoted 2 lines
Acked-by Dan Williams <[email protected]>
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Re: dm, dax: Make sure dm_dax_flush() is called if device supports it
In reply to Vivek GoyalQuoted 7 lines · Vivek Goyal
Right now,
dm_dax_flush()is not being called and I think it is not being called becuaseDAXDEV_WRITE_CACHEis not set on dm dax device.If underlying dax device supports write cache, set
DAXDEV_WRITE_CACHEon dm dax device. This will getdm_dax_flush()being called.Signed-off-by Vivek Goyal <[email protected]>
In general this looks mostly OK.. but it seems a bit weird to on the one
hand: test if DAXDEV_WRITE_CACHE is set on underlying device. And on the other: say it is a write cache because it is "flush_capable". Kind of blurring things a bit.
Why not s/device_dax_flush_capable/device_dax_write_cache_enabled/ ?
Mike
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Quoted 9 lines · Mike Snitzer
Quoted 6 lines · Vivek Goyal
Right now,
dm_dax_flush()is not being called and I think it is not being called becuaseDAXDEV_WRITE_CACHEis not set on dm dax device.If underlying dax device supports write cache, set
DAXDEV_WRITE_CACHEon dm dax device. This will getdm_dax_flush()being called.
Quoted 8 lines
Quoted 1 line
Signed-off-by Vivek Goyal <[email protected]>In general this looks mostly OK.. but it seems a bit weird to on the one
hand: test ifDAXDEV_WRITE_CACHEis set on underlying device. And on the other: say it is a write cache because it is "flush_capable". Kind of blurring things a bit.Why not s/device_dax_flush_capable/device_dax_write_cache_enabled/ ?
Sounds good. I will rename it in next version.
Vivek
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