On 3/11/2026 5:27 PM, Dan Williams wrote:
Smita Koralahalli wrote:
Introduce a global "DAX Regions" resource root and register each
dax_region->res under it via request_resource(). Release the resource on
dax_region teardown.
By enforcing a single global namespace for dax_region allocations, this
ensures only one of dax_hmem or dax_cxl can successfully register a
dax_region for a given range.
Co-developed-by: Dan Williams <[email protected]>
Did I send any code for this? If I suggested the locking below,
apologies, otherwise Suggested-by is expected unless code is adopted
from another patch.
No sorry the locking was added by me. I will make the changes and drop
the locking.
Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: Smita Koralahalli <[email protected]>
---
drivers/dax/bus.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index fde29e0ad68b..5f387feb95f0 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -10,6 +10,7 @@
#include "dax-private.h"
#include "bus.h"
+static struct resource dax_regions = DEFINE_RES_MEM_NAMED(0, -1, "DAX Regions");
static DEFINE_MUTEX(dax_bus_lock);
/*
@@ -625,6 +626,8 @@ static void dax_region_unregister(void *region)
{
struct dax_region *dax_region = region;
+ scoped_guard(rwsem_write, &dax_region_rwsem)
+ release_resource(&dax_region->res);
I continue to dislike what scoped_guard() does to indentation. Often
scoped_guard() usage can just be replaced by "helper that uses guard()"
However, dax_region_rwsem protects subdivision of a dax_region, not
coordination across regions.
Also, release_resource() and request_resource() are already protected by
the resource_lock, why is a new lock needed?
You are right. I will remove
Thanks
Smita
