linux-kernel - [PATCH 5.7 092/265] IB/hfi1: Fix module use count flaw due to leftover module put calls

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Message-Id: <20200629151818.2493727-93-sashal@kernel.org>
Date:   Mon, 29 Jun 2020 11:15:25 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Dennis Dalessandro <dennis.dalessandro@...el.com>,
        Kaike Wan <kaike.wan@...el.com>,
        Mike Marciniszyn <mike.marciniszyn@...el.com>,
        Jason Gunthorpe <jgg@...dia.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH 5.7 092/265] IB/hfi1: Fix module use count flaw due to leftover module put calls

From: Dennis Dalessandro <dennis.dalessandro@...el.com>

commit 822fbd37410639acdae368ea55477ddd3498651d upstream.

When the try_module_get calls were removed from opening and closing of the
i2c debugfs file, the corresponding module_put calls were missed.  This
results in an inaccurate module use count that requires a power cycle to
fix.

Fixes: 09fbca8e6240 ("IB/hfi1: No need to use try_module_get for debugfs")
Link: https://lore.kernel.org/r/20200623203230.106975.76240.stgit@awfm-01.aw.intel.com
Cc: <stable@...r.kernel.org>
Reviewed-by: Kaike Wan <kaike.wan@...el.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@...el.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@...el.com>
Signed-off-by: Jason Gunthorpe <jgg@...dia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/infiniband/hw/hfi1/debugfs.c | 19 ++-----------------
 1 file changed, 2 insertions(+), 17 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/debugfs.c b/drivers/infiniband/hw/hfi1/debugfs.c
index 4633a0ce1a8c0..2ced236e1553c 100644
--- a/drivers/infiniband/hw/hfi1/debugfs.c
+++ b/drivers/infiniband/hw/hfi1/debugfs.c
@@ -985,15 +985,10 @@ static ssize_t qsfp2_debugfs_read(struct file *file, char __user *buf,
 static int __i2c_debugfs_open(struct inode *in, struct file *fp, u32 target)
 {
 	struct hfi1_pportdata *ppd;
-	int ret;
 
 	ppd = private2ppd(fp);
 
-	ret = acquire_chip_resource(ppd->dd, i2c_target(target), 0);
-	if (ret) /* failed - release the module */
-		module_put(THIS_MODULE);
-
-	return ret;
+	return acquire_chip_resource(ppd->dd, i2c_target(target), 0);
 }
 
 static int i2c1_debugfs_open(struct inode *in, struct file *fp)
@@ -1013,7 +1008,6 @@ static int __i2c_debugfs_release(struct inode *in, struct file *fp, u32 target)
 	ppd = private2ppd(fp);
 
 	release_chip_resource(ppd->dd, i2c_target(target));
-	module_put(THIS_MODULE);
 
 	return 0;
 }
@@ -1031,18 +1025,10 @@ static int i2c2_debugfs_release(struct inode *in, struct file *fp)
 static int __qsfp_debugfs_open(struct inode *in, struct file *fp, u32 target)
 {
 	struct hfi1_pportdata *ppd;
-	int ret;
-
-	if (!try_module_get(THIS_MODULE))
-		return -ENODEV;
 
 	ppd = private2ppd(fp);
 
-	ret = acquire_chip_resource(ppd->dd, i2c_target(target), 0);
-	if (ret) /* failed - release the module */
-		module_put(THIS_MODULE);
-
-	return ret;
+	return acquire_chip_resource(ppd->dd, i2c_target(target), 0);
 }
 
 static int qsfp1_debugfs_open(struct inode *in, struct file *fp)
@@ -1062,7 +1048,6 @@ static int __qsfp_debugfs_release(struct inode *in, struct file *fp, u32 target)
 	ppd = private2ppd(fp);
 
 	release_chip_resource(ppd->dd, i2c_target(target));
-	module_put(THIS_MODULE);
 
 	return 0;
 }
-- 
2.25.1