From: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
match_free_decoder()'s logic for finding a free cxl decoder depends on
a prerequisite that all child decoders are sorted by ID in ascending order
but the prerequisite may not be guaranteed, fix by finding a free cxl
decoder with minimal ID.
Fixes: 384e624bb211 ("cxl/region: Attach endpoint decoders")
Closes: https://lore.kernel.org/all/cdfc6f98-1aa0-4cb5-bd7d-93256552c39b@xxxxxxxxxx/
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
---
drivers/cxl/core/region.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 21ad5f242875..b9607b4fc40b 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -797,21 +797,26 @@ static size_t show_targetN(struct cxl_region *cxlr, char *buf, int pos)
static int match_free_decoder(struct device *dev, void *data)
{
struct cxl_decoder *cxld;
- int *id = data;
+ struct cxl_decoder *target_cxld;
+ struct device **target_device = data;
if (!is_switch_decoder(dev))
return 0;
cxld = to_cxl_decoder(dev);
-
- /* enforce ordered allocation */
- if (cxld->id != *id)
+ if (cxld->region)
return 0;
- if (!cxld->region)
- return 1;
-
- (*id)++;
+ if (!*target_device) {
+ *target_device = get_device(dev);
+ return 0;
+ }
+ /* enforce ordered allocation */
+ target_cxld = to_cxl_decoder(*target_device);
+ if (cxld->id < target_cxld->id) {
+ put_device(*target_device);
+ *target_device = get_device(dev);
+ }
return 0;
}
@@ -839,8 +844,7 @@ cxl_region_find_decoder(struct cxl_port *port,
struct cxl_endpoint_decoder *cxled,
struct cxl_region *cxlr)
{
- struct device *dev;
- int id = 0;
+ struct device *dev = NULL;
if (port == cxled_to_port(cxled))
return &cxled->cxld;
@@ -849,7 +853,8 @@ cxl_region_find_decoder(struct cxl_port *port,
dev = device_find_child(&port->dev, &cxlr->params,
match_auto_decoder);
else
- dev = device_find_child(&port->dev, &id, match_free_decoder);
+ /* Need to put_device(@dev) after use */
+ device_for_each_child(&port->dev, &dev, match_free_decoder);
if (!dev)
return NULL;
/*
---
base-commit: 67784a74e258a467225f0e68335df77acd67b7ab
change-id: 20240903-fix_cxld-4f6575a90619
Best regards,
--
Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
