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Subject[PATCH AUTOSEL 4.19 031/192] f2fs: do not use mutex lock in atomic context
Date
From: Sahitya Tummala <stummala@codeaurora.org>

[ Upstream commit 9083977dabf3833298ddcd40dee28687f1e6b483 ]

Fix below warning coming because of using mutex lock in atomic context.

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:98
in_atomic(): 1, irqs_disabled(): 0, pid: 585, name: sh
Preemption disabled at: __radix_tree_preload+0x28/0x130
Call trace:
dump_backtrace+0x0/0x2b4
show_stack+0x20/0x28
dump_stack+0xa8/0xe0
___might_sleep+0x144/0x194
__might_sleep+0x58/0x8c
mutex_lock+0x2c/0x48
f2fs_trace_pid+0x88/0x14c
f2fs_set_node_page_dirty+0xd0/0x184

Do not use f2fs_radix_tree_insert() to avoid doing cond_resched() with
spin_lock() acquired.

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/trace.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/trace.c b/fs/f2fs/trace.c
index a1fcd00bbb2b..8ac1851a21c0 100644
--- a/fs/f2fs/trace.c
+++ b/fs/f2fs/trace.c
@@ -17,7 +17,7 @@
#include "trace.h"

static RADIX_TREE(pids, GFP_ATOMIC);
-static struct mutex pids_lock;
+static spinlock_t pids_lock;
static struct last_io_info last_io;

static inline void __print_last_io(void)
@@ -61,23 +61,29 @@ void f2fs_trace_pid(struct page *page)

set_page_private(page, (unsigned long)pid);

+retry:
if (radix_tree_preload(GFP_NOFS))
return;

- mutex_lock(&pids_lock);
+ spin_lock(&pids_lock);
p = radix_tree_lookup(&pids, pid);
if (p == current)
goto out;
if (p)
radix_tree_delete(&pids, pid);

- f2fs_radix_tree_insert(&pids, pid, current);
+ if (radix_tree_insert(&pids, pid, current)) {
+ spin_unlock(&pids_lock);
+ radix_tree_preload_end();
+ cond_resched();
+ goto retry;
+ }

trace_printk("%3x:%3x %4x %-16s\n",
MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
pid, current->comm);
out:
- mutex_unlock(&pids_lock);
+ spin_unlock(&pids_lock);
radix_tree_preload_end();
}

@@ -122,7 +128,7 @@ void f2fs_trace_ios(struct f2fs_io_info *fio, int flush)

void f2fs_build_trace_ios(void)
{
- mutex_init(&pids_lock);
+ spin_lock_init(&pids_lock);
}

#define PIDVEC_SIZE 128
@@ -150,7 +156,7 @@ void f2fs_destroy_trace_ios(void)
pid_t next_pid = 0;
unsigned int found;

- mutex_lock(&pids_lock);
+ spin_lock(&pids_lock);
while ((found = gang_lookup_pids(pid, next_pid, PIDVEC_SIZE))) {
unsigned idx;

@@ -158,5 +164,5 @@ void f2fs_destroy_trace_ios(void)
for (idx = 0; idx < found; idx++)
radix_tree_delete(&pids, pid[idx]);
}
- mutex_unlock(&pids_lock);
+ spin_unlock(&pids_lock);
}
--
2.19.1
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