zram: remove workqueue for freeing removed pending slot

Commit a0c516cbfc74 ("zram: don't grab mutex in zram_slot_free_noity")
introduced free request pending code to avoid scheduling by mutex under
spinlock and it was a mess which made code lenghty and increased
overhead.

Now, we don't need zram->lock any more to free slot so this patch
reverts it and then, tb_lock should protect it.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 24e6426..f1a3c95 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -522,20 +522,6 @@ out:
        return ret;
 }
 
-static void handle_pending_slot_free(struct zram *zram)
-{
-       struct zram_slot_free *free_rq;
-
-       spin_lock(&zram->slot_free_lock);
-       while (zram->slot_free_rq) {
-               free_rq = zram->slot_free_rq;
-               zram->slot_free_rq = free_rq->next;
-               zram_free_page(zram, free_rq->index);
-               kfree(free_rq);
-       }
-       spin_unlock(&zram->slot_free_lock);
-}
-
 static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
                        int offset, struct bio *bio, int rw)
 {
@@ -547,7 +533,6 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
                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);
        }
@@ -566,8 +551,6 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
                return;
        }
 
-       flush_work(&zram->free_work);
-
        meta = zram->meta;
        zram->init_done = 0;
 
@@ -769,40 +752,19 @@ error:
        bio_io_error(bio);
 }
 
-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)
-{
-       spin_lock(&zram->slot_free_lock);
-       free_rq->next = zram->slot_free_rq;
-       zram->slot_free_rq = free_rq;
-       spin_unlock(&zram->slot_free_lock);
-}
-
 static void zram_slot_free_notify(struct block_device *bdev,
                                unsigned long index)
 {
        struct zram *zram;
-       struct zram_slot_free *free_rq;
+       struct zram_meta *meta;
 
        zram = bdev->bd_disk->private_data;
-       atomic64_inc(&zram->stats.notify_free);
-
-       free_rq = kmalloc(sizeof(struct zram_slot_free), GFP_ATOMIC);
-       if (!free_rq)
-               return;
+       meta = zram->meta;
 
-       free_rq->index = index;
-       add_slot_free(zram, free_rq);
-       schedule_work(&zram->free_work);
+       write_lock(&meta->tb_lock);
+       zram_free_page(zram, index);
+       write_unlock(&meta->tb_lock);
+       atomic64_inc(&zram->stats.notify_free);
 }
 
 static const struct block_device_operations zram_devops = {
@@ -849,10 +811,6 @@ static int create_device(struct zram *zram, int device_id)
        init_rwsem(&zram->lock);
        init_rwsem(&zram->init_lock);
 
-       INIT_WORK(&zram->free_work, zram_slot_free);
-       spin_lock_init(&zram->slot_free_lock);
-       zram->slot_free_rq = NULL;
-
        zram->queue = blk_alloc_queue(GFP_KERNEL);
        if (!zram->queue) {
                pr_err("Error allocating disk queue for device %d\n",

diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index c3f453f..d876300 100644 (file)
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -90,20 +90,11 @@ struct zram_meta {
        struct zs_pool *mem_pool;
 };
 
-struct zram_slot_free {
-       unsigned long index;
-       struct zram_slot_free *next;
-};
-
 struct zram {
        struct zram_meta *meta;
        struct rw_semaphore lock; /* protect compression buffers,
                                   * reads and writes
                                   */
-
-       struct work_struct free_work;  /* handle pending free request */
-       struct zram_slot_free *slot_free_rq; /* list head of free request */
-
        struct request_queue *queue;
        struct gendisk *disk;
        int init_done;
@@ -114,7 +105,6 @@ struct zram {
         * we can store in a disk.
         */
        u64 disksize;   /* bytes */
-       spinlock_t slot_free_lock;
 
        struct zram_stats stats;
 };