Merge branch 'for-6.7/cxl' into for-6.8/cxl

Pick up a late locking change + fixup that is better as merge window
material than rc material.

Author: djbw

drivers/cxl/core/cdat.c

@@ -7,6 +7,7 @@
 #include <linux/overflow.h>
 #include "cxlpci.h"
 #include "cxlmem.h"
+#include "core.h"
 #include "cxl.h"
 
 struct dsmas_entry {
@@ -317,21 +318,18 @@ static int match_cxlrd_hb(struct device *dev, void *data)
 	struct device *host_bridge = data;
 	struct cxl_switch_decoder *cxlsd;
 	struct cxl_root_decoder *cxlrd;
-	unsigned int seq;
 
 	if (!is_root_decoder(dev))
 		return 0;
 
 	cxlrd = to_cxl_root_decoder(dev);
 	cxlsd = &cxlrd->cxlsd;
 
-	do {
-		seq = read_seqbegin(&cxlsd->target_lock);
-		for (int i = 0; i < cxlsd->nr_targets; i++) {
-			if (host_bridge == cxlsd->target[i]->dport_dev)
-				return 1;
-		}
-	} while (read_seqretry(&cxlsd->target_lock, seq));
+	guard(rwsem_read)(&cxl_region_rwsem);
+	for (int i = 0; i < cxlsd->nr_targets; i++) {
+		if (host_bridge == cxlsd->target[i]->dport_dev)
+			return 1;
+	}
 
 	return 0;
 }

drivers/cxl/core/port.c

@@ -173,14 +173,10 @@ static ssize_t target_list_show(struct device *dev,
 {
 	struct cxl_switch_decoder *cxlsd = to_cxl_switch_decoder(dev);
 	ssize_t offset;
-	unsigned int seq;
 	int rc;
 
-	do {
-		seq = read_seqbegin(&cxlsd->target_lock);
-		rc = emit_target_list(cxlsd, buf);
-	} while (read_seqretry(&cxlsd->target_lock, seq));
-
+	guard(rwsem_read)(&cxl_region_rwsem);
+	rc = emit_target_list(cxlsd, buf);
 	if (rc < 0)
 		return rc;
 	offset = rc;
@@ -1678,7 +1674,7 @@ EXPORT_SYMBOL_NS_GPL(cxl_mem_find_port, CXL);
 static int decoder_populate_targets(struct cxl_switch_decoder *cxlsd,
 				    struct cxl_port *port, int *target_map)
 {
-	int i, rc = 0;
+	int i;
 
 	if (!target_map)
 		return 0;
@@ -1688,19 +1684,16 @@ static int decoder_populate_targets(struct cxl_switch_decoder *cxlsd,
 	if (xa_empty(&port->dports))
 		return -EINVAL;
 
-	write_seqlock(&cxlsd->target_lock);
-	for (i = 0; i < cxlsd->nr_targets; i++) {
+	guard(rwsem_write)(&cxl_region_rwsem);
+	for (i = 0; i < cxlsd->cxld.interleave_ways; i++) {
 		struct cxl_dport *dport = find_dport(port, target_map[i]);
 
-		if (!dport) {
-			rc = -ENXIO;
-			break;
-		}
+		if (!dport)
+			return -ENXIO;
 		cxlsd->target[i] = dport;
 	}
-	write_sequnlock(&cxlsd->target_lock);
 
-	return rc;
+	return 0;
 }
 
 struct cxl_dport *cxl_hb_modulo(struct cxl_root_decoder *cxlrd, int pos)
@@ -1770,7 +1763,6 @@ static int cxl_switch_decoder_init(struct cxl_port *port,
 		return -EINVAL;
 
 	cxlsd->nr_targets = nr_targets;
-	seqlock_init(&cxlsd->target_lock);
 	return cxl_decoder_init(port, &cxlsd->cxld);
 }
 

drivers/cxl/cxl.h

@@ -413,7 +413,6 @@ struct cxl_endpoint_decoder {
 /**
  * struct cxl_switch_decoder - Switch specific CXL HDM Decoder
  * @cxld: base cxl_decoder object
- * @target_lock: coordinate coherent reads of the target list
  * @nr_targets: number of elements in @target
  * @target: active ordered target list in current decoder configuration
  *
@@ -425,7 +424,6 @@ struct cxl_endpoint_decoder {
  */
 struct cxl_switch_decoder {
 	struct cxl_decoder cxld;
-	seqlock_t target_lock;
 	int nr_targets;
 	struct cxl_dport *target[];
 };