Calling handle_pending_slot_free() for every RW operation may
cause unneccessary slot_free_lock locking, because most likely
process will see NULL slot_free_rq. handle_pending_slot_free()
only when current detects that slot_free_rq is not NULL.
v3: do not acquire zram lock in zram_slot_free().
v2: protect handle_pending_slot_free() with zram rw_lock.
Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
---
drivers/staging/zram/zram_drv.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 91d94b5..a8261b4 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -517,6 +517,7 @@ static void handle_pending_slot_free(struct zram *zram)
{
struct zram_slot_free *free_rq;
+ down_write(&zram->lock);
spin_lock(&zram->slot_free_lock);
while (zram->slot_free_rq) {
free_rq = zram->slot_free_rq;
@@ -525,6 +526,7 @@ static void handle_pending_slot_free(struct zram *zram)
kfree(free_rq);
}
spin_unlock(&zram->slot_free_lock);
+ up_write(&zram->lock);
}
static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
@@ -532,14 +534,15 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec
*bvec, u32 index,
{
int ret;
+ if (zram->slot_free_rq)
+ handle_pending_slot_free(zram);
+
if (rw == READ) {
down_read(&zram->lock);
- handle_pending_slot_free(zram);
ret = zram_bvec_read(zram, bvec, index, offset, bio);
up_read(&zram->lock);
} else {
down_write(&zram->lock);
- handle_pending_slot_free(zram);
ret = zram_bvec_write(zram, bvec, index, offset);
up_write(&zram->lock);
}
@@ -753,9 +756,7 @@ static void zram_slot_free(struct work_struct *work)
struct zram *zram;
zram = container_of(work, struct zram, free_work);
- down_write(&zram->lock);
handle_pending_slot_free(zram);
- up_write(&zram->lock);
}
static void add_slot_free(struct zram *zram, struct zram_slot_free *free_rq)
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