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Commit 22fe1ae8 authored by Matthew R. Ochs's avatar Matthew R. Ochs Committed by James Bottomley
Browse files

cxlflash: Fix potential oops following LUN removal 



When a LUN is removed, the sdev that is associated with the LUN
remains intact until its reference count drops to 0. In order
to prevent an sdev from being removed while a context is still
associated with it, obtain an additional reference per-context
for each LUN attached to the context.

This resolves a potential Oops in the release handler when a
dealing with a LUN that has already been removed.

Signed-off-by: default avatarMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: default avatarManoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: default avatarBrian King <brking@linux.vnet.ibm.com>
Reviewed-by: default avatarTomas Henzl <thenzl@redhat.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Odin.com>
parent 471a5a60

drivers/scsi/cxlflash/superpipe.c

+23 −12
Original line number Original line Diff line number Diff line
@@ -880,6 +880,9 @@ static int _cxlflash_disk_detach(struct scsi_device *sdev, 
			sys_close(lfd);

			sys_close(lfd);

	}

	}





	/* Release the sdev reference that bound this LUN to the context */

	scsi_device_put(sdev);



out:

out:

	if (put_ctx)

	if (put_ctx)

		put_context(ctxi);

		put_context(ctxi);
@@ -1287,11 +1290,17 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, 
			}

			}

	}

	}





	rc = scsi_device_get(sdev);

	if (unlikely(rc)) {

		dev_err(dev, "%s: Unable to get sdev reference!\n", __func__);

		goto out;

	}



	lun_access = kzalloc(sizeof(*lun_access), GFP_KERNEL);

	lun_access = kzalloc(sizeof(*lun_access), GFP_KERNEL);

	if (unlikely(!lun_access)) {

	if (unlikely(!lun_access)) {

		dev_err(dev, "%s: Unable to allocate lun_access!\n", __func__);

		dev_err(dev, "%s: Unable to allocate lun_access!\n", __func__);

		rc = -ENOMEM;

		rc = -ENOMEM;

		goto out;

		goto err0;

	}

	}





	lun_access->lli = lli;

	lun_access->lli = lli;
@@ -1311,21 +1320,21 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, 
		dev_err(dev, "%s: Could not initialize context %p\n",

		dev_err(dev, "%s: Could not initialize context %p\n",

			__func__, ctx);

			__func__, ctx);

		rc = -ENODEV;

		rc = -ENODEV;

		goto err0;

		goto err1;

	}

	}





	ctxid = cxl_process_element(ctx);

	ctxid = cxl_process_element(ctx);

	if (unlikely((ctxid > MAX_CONTEXT) || (ctxid < 0))) {

	if (unlikely((ctxid > MAX_CONTEXT) || (ctxid < 0))) {

		dev_err(dev, "%s: ctxid (%d) invalid!\n", __func__, ctxid);

		dev_err(dev, "%s: ctxid (%d) invalid!\n", __func__, ctxid);

		rc = -EPERM;

		rc = -EPERM;

		goto err1;

		goto err2;

	}

	}





	file = cxl_get_fd(ctx, &cfg->cxl_fops, &fd);

	file = cxl_get_fd(ctx, &cfg->cxl_fops, &fd);

	if (unlikely(fd < 0)) {

	if (unlikely(fd < 0)) {

		rc = -ENODEV;

		rc = -ENODEV;

		dev_err(dev, "%s: Could not get file descriptor\n", __func__);

		dev_err(dev, "%s: Could not get file descriptor\n", __func__);

		goto err1;

		goto err2;

	}

	}





	/* Translate read/write O_* flags from fcntl.h to AFU permission bits */

	/* Translate read/write O_* flags from fcntl.h to AFU permission bits */
@@ -1335,7 +1344,7 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, 
	if (unlikely(!ctxi)) {

	if (unlikely(!ctxi)) {

		dev_err(dev, "%s: Failed to create context! (%d)\n",

		dev_err(dev, "%s: Failed to create context! (%d)\n",

			__func__, ctxid);

			__func__, ctxid);

		goto err2;

		goto err3;

	}

	}





	work = &ctxi->work;

	work = &ctxi->work;
@@ -1346,13 +1355,13 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, 
	if (unlikely(rc)) {

	if (unlikely(rc)) {

		dev_dbg(dev, "%s: Could not start context rc=%d\n",

		dev_dbg(dev, "%s: Could not start context rc=%d\n",

			__func__, rc);

			__func__, rc);

		goto err3;

		goto err4;

	}

	}





	rc = afu_attach(cfg, ctxi);

	rc = afu_attach(cfg, ctxi);

	if (unlikely(rc)) {

	if (unlikely(rc)) {

		dev_err(dev, "%s: Could not attach AFU rc %d\n", __func__, rc);

		dev_err(dev, "%s: Could not attach AFU rc %d\n", __func__, rc);

		goto err4;

		goto err5;

	}

	}





	/*

	/*
@@ -1388,13 +1397,13 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, 
		__func__, ctxid, fd, attach->block_size, rc, attach->last_lba);

		__func__, ctxid, fd, attach->block_size, rc, attach->last_lba);

	return rc;

	return rc;





err4:

err5:

	cxl_stop_context(ctx);

	cxl_stop_context(ctx);

err3:

err4:

	put_context(ctxi);

	put_context(ctxi);

	destroy_context(cfg, ctxi);

	destroy_context(cfg, ctxi);

	ctxi = NULL;

	ctxi = NULL;

err2:

err3:

	/*

	/*

	 * Here, we're overriding the fops with a dummy all-NULL fops because

	 * Here, we're overriding the fops with a dummy all-NULL fops because

	 * fput() calls the release fop, which will cause us to mistakenly

	 * fput() calls the release fop, which will cause us to mistakenly
@@ -1406,10 +1415,12 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, 
	fput(file);

	fput(file);

	put_unused_fd(fd);

	put_unused_fd(fd);

	fd = -1;

	fd = -1;

err1:

err2:

	cxl_release_context(ctx);

	cxl_release_context(ctx);

err0:

err1:

	kfree(lun_access);

	kfree(lun_access);

err0:

	scsi_device_put(sdev);

	goto out;

	goto out;

}

}