Messages in this thread Patch in this message | | | From | Zhen Lei <> | Subject | [PATCH v2 2/2] libnvdimm/badrange: eliminate a meaningless spinlock operation | Date | Sat, 19 Sep 2020 18:45:46 +0800 |
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badrange_add() take the lock "badrange->lock", but it's released immediately in add_badrange(), protect nothing.
The pseudo code is as follows: In badrange_add(): spin_lock(&badrange->lock); <--------------- rc = add_badrange(badrange, addr, length); | In add_badrange(): | //do nothing | spin_unlock(&badrange->lock); <--------------- bre_new = kzalloc(sizeof(*bre_new), GFP_KERNEL); spin_lock(&badrange->lock); <--- lock again
This lock/unlock operation is meaningless.
Because the static function add_badrange() is only called by badrange_add(), so move its content into badrange_add() then delete it. By the way, move "kfree(bre_new)" out of the lock protection, it really doesn't need.
Fixes: b3b454f694db ("libnvdimm: fix clear poison locking with spinlock ...") Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> --- drivers/nvdimm/badrange.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-)
diff --git a/drivers/nvdimm/badrange.c b/drivers/nvdimm/badrange.c index 9fdba8c43e8605e..7f78b659057902d 100644 --- a/drivers/nvdimm/badrange.c +++ b/drivers/nvdimm/badrange.c @@ -45,12 +45,12 @@ static int alloc_and_append_badrange_entry(struct badrange *badrange, return 0; } -static int add_badrange(struct badrange *badrange, u64 addr, u64 length) +int badrange_add(struct badrange *badrange, u64 addr, u64 length) { struct badrange_entry *bre, *bre_new; - spin_unlock(&badrange->lock); bre_new = kzalloc(sizeof(*bre_new), GFP_KERNEL); + spin_lock(&badrange->lock); /* @@ -63,6 +63,7 @@ static int add_badrange(struct badrange *badrange, u64 addr, u64 length) /* If length has changed, update this list entry */ if (bre->length != length) bre->length = length; + spin_unlock(&badrange->lock); kfree(bre_new); return 0; } @@ -72,22 +73,15 @@ static int add_badrange(struct badrange *badrange, u64 addr, u64 length) * as any overlapping ranges will get resolved when the list is consumed * and converted to badblocks */ - if (!bre_new) + if (!bre_new) { + spin_unlock(&badrange->lock); return -ENOMEM; - append_badrange_entry(badrange, bre_new, addr, length); - - return 0; -} - -int badrange_add(struct badrange *badrange, u64 addr, u64 length) -{ - int rc; + } - spin_lock(&badrange->lock); - rc = add_badrange(badrange, addr, length); + append_badrange_entry(badrange, bre_new, addr, length); spin_unlock(&badrange->lock); - return rc; + return 0; } EXPORT_SYMBOL_GPL(badrange_add); -- 1.8.3
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