From: "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>
Date: Wed, 25 Oct 2017 16:36:29 -0500
Subject: [PATCH] scsi: cxlflash: Derive pid through accessors
References: bsc#1077989
Git-commit: d84c198f43c50c6c0bd57571acbf0f000165bd56
Patch-mainline: v4.15-rc1

The cxlflash driver tracks process IDs alongside contexts to validate
context ownership. Currently, the process IDs are derived by directly
accessing values from the 'current' task pointer. While this method of
access is fine for the current process, it is incorrect when the parent
process ID is needed as the access requires serialization.

To address the incorrect issue and provide a consistent means of
deriving the process ID within the cxlflash driver, use the task
accessors defined linux/sched.h.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/cxlflash/superpipe.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c
index ed46e8df2e42..170fff5aeff6 100644
--- a/drivers/scsi/cxlflash/superpipe.c
+++ b/drivers/scsi/cxlflash/superpipe.c
@@ -165,7 +165,7 @@ struct ctx_info *get_context(struct cxlflash_cfg *cfg, u64 rctxid,
 	struct llun_info *lli = arg;
 	u64 ctxid = DECODE_CTXID(rctxid);
 	int rc;
-	pid_t pid = current->tgid, ctxpid = 0;
+	pid_t pid = task_tgid_nr(current), ctxpid = 0;
 
 	if (ctx_ctrl & CTX_CTRL_FILE) {
 		lli = NULL;
@@ -173,7 +173,7 @@ struct ctx_info *get_context(struct cxlflash_cfg *cfg, u64 rctxid,
 	}
 
 	if (ctx_ctrl & CTX_CTRL_CLONE)
-		pid = current->parent->tgid;
+		pid = task_ppid_nr(current);
 
 	if (likely(ctxid < MAX_CONTEXT)) {
 		while (true) {
@@ -824,7 +824,7 @@ static void init_context(struct ctx_info *ctxi, struct cxlflash_cfg *cfg,
 	ctxi->rht_perms = perms;
 	ctxi->ctrl_map = &afu->afu_map->ctrls[ctxid].ctrl;
 	ctxi->ctxid = ENCODE_CTXID(ctxi, ctxid);
-	ctxi->pid = current->tgid; /* tgid = pid */
+	ctxi->pid = task_tgid_nr(current); /* tgid = pid */
 	ctxi->ctx = ctx;
 	ctxi->cfg = cfg;
 	ctxi->file = file;
-- 
2.12.3