Re: [PATCH v2 12/38] cxlflash: Use IDR to manage adapter contexts

On Mar 22, 2018, at 11:40 AM, Frederic Barrat =

[off-list ref] wrote:

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Le 26/02/2018 =C3=A0 23:21, Uma Krishnan a =C3=A9crit :

quoted

A range of PASIDs are used as identifiers for the adapter contexts. =

These

quoted

contexts may be destroyed and created randomly. Use an IDR to keep =

track

quoted

of contexts that are in use and assign a unique identifier to new =

ones.

quoted

Signed-off-by: Uma Krishnan <redacted>
Acked-by: Matthew R. Ochs <redacted>
---
 drivers/scsi/cxlflash/ocxl_hw.c | 20 ++++++++++++++++++--
 drivers/scsi/cxlflash/ocxl_hw.h |  2 ++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/cxlflash/ocxl_hw.c =

b/drivers/scsi/cxlflash/ocxl_hw.c

quoted

index d75b873..6472210 100644

--- a/drivers/scsi/cxlflash/ocxl_hw.c
+++ b/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)

quoted

 	if (unlikely(!ctx)) {
 		dev_err(dev, "%s: Context allocation failed\n", =

__func__);

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 		rc =3D -ENOMEM;
-		goto err;
+		goto err1;
+	}
+
+	idr_preload(GFP_KERNEL);
+	rc =3D idr_alloc(&afu->idr, ctx, 0, afu->max_pasid, GFP_NOWAIT);
+	idr_preload_end();

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I believe we can call idr_alloc(... GFP_KERNEL) directly in that
context now.
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quoted

+	if (unlikely(rc < 0)) {
+		dev_err(dev, "%s: idr_alloc failed rc=3D%d\n", __func__, =

rc);

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+		goto err2;
 	}
+	ctx->pe =3D rc;
 	ctx->master =3D false;
 	ctx->hw_afu =3D afu;
 out:
 	return ctx;
-err:
+err2:
+	kfree(ctx);
+err1:
 	ctx =3D ERR_PTR(rc);
 	goto out;
 }

@@ -86,6 +99,7 @@ static int ocxlflash_release_context(void =

*ctx_cookie)

quoted

 	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)

quoted

 		return;
 	ocxlflash_release_context(afu->ocxl_ctx);
+	idr_destroy(&afu->idr);
 	kfree(afu);
 }

@@ -237,6 +252,7 @@ static void *ocxlflash_create_afu(struct pci_dev =

*pdev)

quoted

 		goto err1;
 	}
+	idr_init(&afu->idr);

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You initialize the IDR too late. ocxlflash_dev_context_init() was =

called just above and allocated a PE.

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 Fred

Good Catch. I will fix this bug and send out a V3 soon. Thanks for the =
review !!

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quoted

 	afu->ocxl_ctx =3D ctx;
 out:
 	return afu;

diff --git a/drivers/scsi/cxlflash/ocxl_hw.h =

b/drivers/scsi/cxlflash/ocxl_hw.h

quoted

index de43c04..0381682 100644

--- a/drivers/scsi/cxlflash/ocxl_hw.h
+++ b/drivers/scsi/cxlflash/ocxl_hw.h

@@ -26,10 +26,12 @@ 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 */
 };
 struct ocxlflash_context {
 	struct ocxl_hw_afu *hw_afu;	/* HW AFU back pointer */
 	bool master;			/* Whether this is a master =

context */

quoted

+	int pe;				/* Process element */
 };

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