scsi: cxlflash: Use IDR to manage adapter contexts

A range of PASIDs are used as identifiers for the adapter contexts. These
contexts may be destroyed and created randomly. Use an IDR to keep track of
contexts that are in use and assign a unique identifier to new ones.
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/cxlflash/ocxl_hw.c

@@ -12,6 +12,8 @@
  * 2 of the License, or (at your option) any later version.
  */
 
+#include <linux/idr.h>
+
 #include <misc/ocxl.h>
 
 #include "backend.h"
@@ -60,14 +62,25 @@ static void *ocxlflash_dev_context_init(struct pci_dev *pdev, void *afu_cookie)
 	if (unlikely(!ctx)) {
 		dev_err(dev, "%s: Context allocation failed\n", __func__);
 		rc = -ENOMEM;
-		goto err;
+		goto err1;
+	}
+
+	idr_preload(GFP_KERNEL);
+	rc = idr_alloc(&afu->idr, ctx, 0, afu->max_pasid, GFP_NOWAIT);
+	idr_preload_end();
+	if (unlikely(rc < 0)) {
+		dev_err(dev, "%s: idr_alloc failed rc=%d\n", __func__, rc);
+		goto err2;
 	}
 
+	ctx->pe = rc;
 	ctx->master = false;
 	ctx->hw_afu = afu;
 out:
 	return ctx;
-err:
+err2:
+	kfree(ctx);
+err1:
 	ctx = ERR_PTR(rc);
 	goto out;
 }
@@ -86,6 +99,7 @@ static int ocxlflash_release_context(void *ctx_cookie)
 	if (!ctx)
 		goto out;
 
+	idr_remove(&ctx->hw_afu->idr, ctx->pe);
 	kfree(ctx);
 out:
 	return rc;
@@ -103,6 +117,7 @@ static void ocxlflash_destroy_afu(void *afu_cookie)
 		return;
 
 	ocxlflash_release_context(afu->ocxl_ctx);
+	idr_destroy(&afu->idr);
 	kfree(afu);
 }
 
@@ -221,6 +236,7 @@ static void *ocxlflash_create_afu(struct pci_dev *pdev)
 
 	afu->pdev = pdev;
 	afu->dev = dev;
+	idr_init(&afu->idr);
 
 	rc = ocxlflash_config_fn(pdev, afu);
 	if (unlikely(rc)) {
@@ -248,6 +264,7 @@ static void *ocxlflash_create_afu(struct pci_dev *pdev)
 out:
 	return afu;
 err1:
+	idr_destroy(&afu->idr);
 	kfree(afu);
 	afu = NULL;
 	goto out;

drivers/scsi/cxlflash/ocxl_hw.h

@@ -26,6 +26,7 @@ struct ocxl_hw_afu {
 	int afu_actag_base;		/* AFU acTag base */
 	int afu_actag_enabled;		/* AFU acTag number enabled */
 
+	struct idr idr;			/* IDR to manage contexts */
 	int max_pasid;			/* Maximum number of contexts */
 	bool is_present;		/* Function has AFUs defined */
 };
@@ -33,4 +34,5 @@ struct ocxl_hw_afu {
 struct ocxlflash_context {
 	struct ocxl_hw_afu *hw_afu;	/* HW AFU back pointer */
 	bool master;			/* Whether this is a master context */
+	int pe;				/* Process element */
 };