From 8cbf9ac9941fceb2a39e11a5702489b46fbb4aca Mon Sep 17 00:00:00 2001

From: Maurizio Lombardi <mlombard@redhat.com>

Date: Mon, 6 Sep 2021 17:18:09 +0200

Subject: [PATCH] scsi: target: Fix the pgr/alua_support_store functions

Git-commit: ef7ae7f746e95c6fa4ec2bcfacb949c36263da78

Patch-mainline: v5.15-rc3

References: stable-5.14.9

[ Upstream commit ef7ae7f746e95c6fa4ec2bcfacb949c36263da78 ]

Commit 356ba2a8bc8d ("scsi: target: tcmu: Make pgr_support and alua_support

attributes writable") introduced support for changeable alua_support and

pgr_support target attributes. These can only be changed if the backstore

is user-backed, otherwise the kernel returns -EINVAL.

This triggers a warning in the targetcli/rtslib code when performing a

target restore that includes non-userbacked backstores:

  # targetctl restore

  Storage Object block/storage1: Cannot set attribute alua_support:

  [Errno 22] Invalid argument, skipped

  Storage Object block/storage1: Cannot set attribute pgr_support:

  [Errno 22] Invalid argument, skipped

Fix this warning by returning an error code only if we are really going to

flip the PGR/ALUA bit in the transport_flags field, otherwise we will do

nothing and return success.

Return ENOSYS instead of EINVAL if the pgr/alua attributes can not be

changed, this way it will be possible for userspace to understand if the

operation failed because an invalid value has been passed to strtobool() or

because the attributes are fixed.

Fixes: 356ba2a8bc8d ("scsi: target: tcmu: Make pgr_support and alua_support attributes writable")

Link: https://lore.kernel.org/r/20210906151809.52811-1-mlombard@redhat.com

Reviewed-by: Bodo Stroesser <bostroesser@gmail.com>

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: Sasha Levin <sashal@kernel.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/target/target_core_configfs.c | 32 +++++++++++++++++----------

 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c

index 102ec644bc8a..023bd4516a68 100644

--- a/drivers/target/target_core_configfs.c

+++ b/drivers/target/target_core_configfs.c

@@ -1110,20 +1110,24 @@ static ssize_t alua_support_store(struct config_item *item,

 {

 	struct se_dev_attrib *da = to_attrib(item);

 	struct se_device *dev = da->da_dev;

-	bool flag;

+	bool flag, oldflag;

 	int ret;

+	ret = strtobool(page, &flag;;

+	if (ret < 0)

+		return ret;

+

+	oldflag = !(dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_ALUA);

+	if (flag == oldflag)

+		return count;

+

 	if (!(dev->transport->transport_flags_changeable &

 	      TRANSPORT_FLAG_PASSTHROUGH_ALUA)) {

 		pr_err("dev[%p]: Unable to change SE Device alua_support:"

 			" alua_support has fixed value\n", dev);

-		return -EINVAL;

+		return -ENOSYS;

 	}

-	ret = strtobool(page, &flag;;

-	if (ret < 0)

-		return ret;

-

 	if (flag)

 		dev->transport_flags &= ~TRANSPORT_FLAG_PASSTHROUGH_ALUA;

 	else

@@ -1145,20 +1149,24 @@ static ssize_t pgr_support_store(struct config_item *item,

 {

 	struct se_dev_attrib *da = to_attrib(item);

 	struct se_device *dev = da->da_dev;

-	bool flag;

+	bool flag, oldflag;

 	int ret;

+	ret = strtobool(page, &flag;;

+	if (ret < 0)

+		return ret;

+

+	oldflag = !(dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR);

+	if (flag == oldflag)

+		return count;

+

 	if (!(dev->transport->transport_flags_changeable &

 	      TRANSPORT_FLAG_PASSTHROUGH_PGR)) {

 		pr_err("dev[%p]: Unable to change SE Device pgr_support:"

 			" pgr_support has fixed value\n", dev);

-		return -EINVAL;

+		return -ENOSYS;

 	}

-	ret = strtobool(page, &flag;;

-	if (ret < 0)

-		return ret;

-

 	if (flag)

 		dev->transport_flags &= ~TRANSPORT_FLAG_PASSTHROUGH_PGR;

 	else

-- 

2.26.2