linux-kernel - [PATCH 2/6] pps: simplify pps_idr

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Message-ID: <20241202163451.1442566-3-mschmidt@redhat.com>
Date: Mon,  2 Dec 2024 17:34:47 +0100
From: Michal Schmidt <mschmidt@...hat.com>
To: Rodolfo Giometti <giometti@...eenne.com>
Cc: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Christophe JAILLET <christophe.jaillet@...adoo.fr>,
	"Dr. David Alan Gilbert" <linux@...blig.org>,
	Ma Ke <make24@...as.ac.cn>,
	Andrew Morton <akpm@...ux-foundation.org>,
	George Spelvin <linux@...izon.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/6] pps: simplify pps_idr_lock locking

It is sufficient to hold pps_idr_lock only around the idr
(de)allocations. There is no reason for the assignment to pps->id or for
the error printing to be under the lock.

Simplify the pps_idr_lock locking and the error path.

Signed-off-by: Michal Schmidt <mschmidt@...hat.com>
---
 drivers/pps/pps.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
index 4f497353daa2..9a631f6d3a1e 100644
--- a/drivers/pps/pps.c
+++ b/drivers/pps/pps.c
@@ -336,22 +336,22 @@ int pps_register_cdev(struct pps_device *pps)
 	int err;
 	dev_t devt;
 
-	mutex_lock(&pps_idr_lock);
 	/*
 	 * Get new ID for the new PPS source.  After idr_alloc() calling
 	 * the new source will be freely available into the kernel.
 	 */
+	mutex_lock(&pps_idr_lock);
 	err = idr_alloc(&pps_idr, pps, 0, PPS_MAX_SOURCES, GFP_KERNEL);
+	mutex_unlock(&pps_idr_lock);
 	if (err < 0) {
 		if (err == -ENOSPC) {
 			pr_err("%s: too many PPS sources in the system\n",
 			       pps->info.name);
 			err = -EBUSY;
 		}
-		goto out_unlock;
+		return err;
 	}
 	pps->id = err;
-	mutex_unlock(&pps_idr_lock);
 
 	devt = MKDEV(MAJOR(pps_devt), pps->id);
 
@@ -389,7 +389,6 @@ int pps_register_cdev(struct pps_device *pps)
 free_idr:
 	mutex_lock(&pps_idr_lock);
 	idr_remove(&pps_idr, pps->id);
-out_unlock:
 	mutex_unlock(&pps_idr_lock);
 	return err;
 }
-- 
2.47.0