From: Vlastimil Babka <vbabka@suse.cz>
Date: Mon, 23 Aug 2021 23:58:57 +0000 (+1000)
Subject: mm, slub: restore irqs around calling new_slab()
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=941f410a941824515f4f2d64517b648f214fb959;p=users%2Fjedix%2Flinux-maple.git

mm, slub: restore irqs around calling new_slab()

allocate_slab() currently re-enables irqs before calling to the page
allocator.  It depends on gfpflags_allow_blocking() to determine if it's
safe to do so.  Now we can instead simply restore irq before calling it
through new_slab().  The other caller early_kmem_cache_node_alloc() is
unaffected by this.

Link: https://lkml.kernel.org/r/20210805152000.12817-16-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---

diff --git a/mm/slub.c b/mm/slub.c
index a437730d7ae24..8b240eb10a1d2 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1795,9 +1795,6 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 
 	flags &= gfp_allowed_mask;
 
-	if (gfpflags_allow_blocking(flags))
-		local_irq_enable();
-
 	flags |= s->allocflags;
 
 	/*
@@ -1856,8 +1853,6 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 	page->frozen = 1;
 
 out:
-	if (gfpflags_allow_blocking(flags))
-		local_irq_disable();
 	if (!page)
 		return NULL;
 
@@ -2798,16 +2793,17 @@ new_objects:
 		goto check_new_page;
 	}
 
+	local_irq_restore(flags);
 	put_cpu_ptr(s->cpu_slab);
 	page = new_slab(s, gfpflags, node);
 	c = get_cpu_ptr(s->cpu_slab);
 
 	if (unlikely(!page)) {
-		local_irq_restore(flags);
 		slab_out_of_memory(s, gfpflags, node);
 		return NULL;
 	}
 
+	local_irq_save(flags);
 	if (c->page)
 		flush_slab(s, c);