[PATCH] scsi: mpt3sas: Fix debugfs setup error handling

[Lei Chen <lei.chen@smartx.com>]

debugfs_create_dir() and debugfs_create_file() return error pointers on
failure, but mpt3sas_setup_debugfs() only checks for NULL. As a result,
setup continues after directory creation fails, and a failure to create
ioc_dump leaves the per-adapter directory behind and still allows setup
of host_recovery to proceed.

Skip per-adapter setup if the driver debugfs root is unavailable, and
use IS_ERR_OR_NULL() to check directory and file creation results so
that the existing error paths also handle error pointers.

With the corrected error check, file creation failure removes the
per-adapter directory. Clear the stored directory pointer as well so
teardown does not attempt to remove the freed dentry again.

Fixes: 2b01b293f359 ("scsi: mpt3sas: Capture IOC data for debugging purposes")
Signed-off-by: Lei Chen <lei.chen@smartx.com>
---
 drivers/scsi/mpt3sas/mpt3sas_debugfs.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_debugfs.c b/drivers/scsi/mpt3sas/mpt3sas_debugfs.c
index 183391f6b8d1..edaeccf538f4 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_debugfs.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_debugfs.c
@@ -120,11 +120,14 @@ mpt3sas_setup_debugfs(struct MPT3SAS_ADAPTER *ioc)
 {
 	char name[64];
 
+	if (IS_ERR_OR_NULL(mpt3sas_debugfs_root))
+		return;
+
 	snprintf(name, sizeof(name), "scsi_host%d", ioc->shost->host_no);
 	if (!ioc->debugfs_root) {
 		ioc->debugfs_root =
 		    debugfs_create_dir(name, mpt3sas_debugfs_root);
-		if (!ioc->debugfs_root) {
+		if (IS_ERR_OR_NULL(ioc->debugfs_root)) {
 			dev_err(&ioc->pdev->dev,
 			    "Cannot create per adapter debugfs directory\n");
 			return;
@@ -134,10 +137,11 @@ mpt3sas_setup_debugfs(struct MPT3SAS_ADAPTER *ioc)
 	snprintf(name, sizeof(name), "ioc_dump");
 	ioc->ioc_dump =	debugfs_create_file(name, 0444,
 	    ioc->debugfs_root, ioc, &mpt3sas_debugfs_iocdump_fops);
-	if (!ioc->ioc_dump) {
+	if (IS_ERR_OR_NULL(ioc->ioc_dump)) {
 		dev_err(&ioc->pdev->dev,
 		    "Cannot create ioc_dump debugfs file\n");
 		debugfs_remove(ioc->debugfs_root);
+		ioc->debugfs_root = NULL;
 		return;
 	}
 
-- 
2.43.0