The patch titled
Subject: mm/swapfile: do not sleep with a spin lock held
has been added to the -mm tree. Its filename is
mm-swapfile-do-not-sleep-with-a-spin-lock-held.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-swapfile-do-not-sleep-with-a-spin-lock-held.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-swapfile-do-not-sleep-with-a-spin-lock-held.patch
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------------------------------------------------------
From: Qian Cai <qcai@xxxxxxxxxx>
Subject: mm/swapfile: do not sleep with a spin lock held
We can't call kvfree() with a spin lock held, so defer it.
Link: https://lkml.kernel.org/r/20201202151549.10350-1-qcai@xxxxxxxxxx
Fixes: 873d7bcfd066 ("mm/swapfile.c: use kvzalloc for swap_info_struct allocation")
Signed-off-by: Qian Cai <qcai@xxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/swapfile.c~mm-swapfile-do-not-sleep-with-a-spin-lock-held
+++ a/mm/swapfile.c
@@ -2867,6 +2867,7 @@ late_initcall(max_swapfiles_check);
static struct swap_info_struct *alloc_swap_info(void)
{
struct swap_info_struct *p;
+ struct swap_info_struct *defer = NULL;
unsigned int type;
int i;
@@ -2895,7 +2896,7 @@ static struct swap_info_struct *alloc_sw
smp_wmb();
WRITE_ONCE(nr_swapfiles, nr_swapfiles + 1);
} else {
- kvfree(p);
+ defer = p;
p = swap_info[type];
/*
* Do not memset this entry: a racing procfs swap_next()
@@ -2908,6 +2909,7 @@ static struct swap_info_struct *alloc_sw
plist_node_init(&p->avail_lists[i], 0);
p->flags = SWP_USED;
spin_unlock(&swap_lock);
+ kvfree(defer);
spin_lock_init(&p->lock);
spin_lock_init(&p->cont_lock);
_
Patches currently in -mm which might be from qcai@xxxxxxxxxx are
mm-swapfile-do-not-sleep-with-a-spin-lock-held.patch
