linux-kernel - [PATCH 5/9] lib/ref_tracker: improve allocation flags

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Date:   Thu, 17 Feb 2022 15:04:37 +0100
From:   Andrzej Hajda <andrzej.hajda@...el.com>
To:     linux-kernel@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, netdev <netdev@...r.kernel.org>
Cc:     Andrzej Hajda <andrzej.hajda@...el.com>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Lucas De Marchi <lucas.demarchi@...el.com>,
        Chris Wilson <chris.p.wilson@...el.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH 5/9] lib/ref_tracker: improve allocation flags

Library can be called in non-sleeping context, so it should not use
__GFP_NOFAIL. Instead it should calmly handle allocation fails, for
this __GFP_NOWARN has been added as well.

Signed-off-by: Andrzej Hajda <andrzej.hajda@...el.com>
---
 lib/ref_tracker.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index 7b00bca300043..c8441ffbb058a 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -59,7 +59,7 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
 	if (list_empty(&dir->list))
 		return;
 
-	sbuf = kmalloc(STACK_BUF_SIZE, GFP_NOWAIT);
+	sbuf = kmalloc(STACK_BUF_SIZE, GFP_NOWAIT | __GFP_NOWARN);
 
 	list_for_each_entry(tracker, &dir->list, head)
 		++total;
@@ -154,11 +154,11 @@ int ref_tracker_alloc(struct ref_tracker_dir *dir,
 	unsigned long entries[REF_TRACKER_STACK_ENTRIES];
 	struct ref_tracker *tracker;
 	unsigned int nr_entries;
-	gfp_t gfp_mask = gfp;
+	gfp_t gfp_mask;
 	unsigned long flags;
 
-	if (gfp & __GFP_DIRECT_RECLAIM)
-		gfp_mask |= __GFP_NOFAIL;
+	gfp |= __GFP_NOWARN;
+	gfp_mask = (gfp & __GFP_DIRECT_RECLAIM) ? (gfp | __GFP_NOFAIL) : gfp;
 	*trackerp = tracker = kzalloc(sizeof(*tracker), gfp_mask);
 	if (unlikely(!tracker)) {
 		pr_err_once("memory allocation failure, unreliable refcount tracker.\n");
@@ -191,7 +191,8 @@ int ref_tracker_free(struct ref_tracker_dir *dir,
 	}
 	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
 	nr_entries = filter_irq_stacks(entries, nr_entries);
-	stack_handle = stack_depot_save(entries, nr_entries, GFP_ATOMIC);
+	stack_handle = stack_depot_save(entries, nr_entries,
+					GFP_NOWAIT | __GFP_NOWARN);
 
 	spin_lock_irqsave(&dir->lock, flags);
 	if (tracker->dead) {
-- 
2.25.1