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-rw-r--r--drivers/block/zram/zram_drv.c76
-rw-r--r--drivers/block/zram/zram_drv.h20
2 files changed, 64 insertions, 32 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 0abcf4a31c78..db94572b35c4 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -53,9 +53,9 @@ static ssize_t name##_show(struct device *d, \
} \
static DEVICE_ATTR_RO(name);
-static inline int init_done(struct zram *zram)
+static inline bool init_done(struct zram *zram)
{
- return zram->meta != NULL;
+ return zram->disksize;
}
static inline struct zram *dev_to_zram(struct device *dev)
@@ -356,6 +356,18 @@ out_error:
return NULL;
}
+static inline bool zram_meta_get(struct zram *zram)
+{
+ if (atomic_inc_not_zero(&zram->refcount))
+ return true;
+ return false;
+}
+
+static inline void zram_meta_put(struct zram *zram)
+{
+ atomic_dec(&zram->refcount);
+}
+
static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
{
if (*offset + bvec->bv_len >= PAGE_SIZE)
@@ -717,6 +729,10 @@ static void zram_bio_discard(struct zram *zram, u32 index,
static void zram_reset_device(struct zram *zram)
{
+ struct zram_meta *meta;
+ struct zcomp *comp;
+ u64 disksize;
+
down_write(&zram->init_lock);
zram->limit_pages = 0;
@@ -726,16 +742,31 @@ static void zram_reset_device(struct zram *zram)
return;
}
- zcomp_destroy(zram->comp);
- zram->max_comp_streams = 1;
- zram_meta_free(zram->meta, zram->disksize);
- zram->meta = NULL;
+ meta = zram->meta;
+ comp = zram->comp;
+ disksize = zram->disksize;
+ /*
+ * Refcount will go down to 0 eventually and r/w handler
+ * cannot handle further I/O so it will bail out by
+ * check zram_meta_get.
+ */
+ zram_meta_put(zram);
+ /*
+ * We want to free zram_meta in process context to avoid
+ * deadlock between reclaim path and any other locks.
+ */
+ wait_event(zram->io_done, atomic_read(&zram->refcount) == 0);
+
/* Reset stats */
memset(&zram->stats, 0, sizeof(zram->stats));
zram->disksize = 0;
+ zram->max_comp_streams = 1;
set_capacity(zram->disk, 0);
up_write(&zram->init_lock);
+ /* I/O operation under all of CPU are done so let's free */
+ zram_meta_free(meta, disksize);
+ zcomp_destroy(comp);
}
static ssize_t disksize_store(struct device *dev,
@@ -771,6 +802,8 @@ static ssize_t disksize_store(struct device *dev,
goto out_destroy_comp;
}
+ init_waitqueue_head(&zram->io_done);
+ atomic_set(&zram->refcount, 1);
zram->meta = meta;
zram->comp = comp;
zram->disksize = disksize;
@@ -901,23 +934,21 @@ static void zram_make_request(struct request_queue *queue, struct bio *bio)
{
struct zram *zram = queue->queuedata;
- down_read(&zram->init_lock);
- if (unlikely(!init_done(zram)))
+ if (unlikely(!zram_meta_get(zram)))
goto error;
if (!valid_io_request(zram, bio->bi_iter.bi_sector,
bio->bi_iter.bi_size)) {
atomic64_inc(&zram->stats.invalid_io);
- goto error;
+ goto put_zram;
}
__zram_make_request(zram, bio);
- up_read(&zram->init_lock);
-
+ zram_meta_put(zram);
return;
-
+put_zram:
+ zram_meta_put(zram);
error:
- up_read(&zram->init_lock);
bio_io_error(bio);
}
@@ -939,21 +970,19 @@ static void zram_slot_free_notify(struct block_device *bdev,
static int zram_rw_page(struct block_device *bdev, sector_t sector,
struct page *page, int rw)
{
- int offset, err;
+ int offset, err = -EIO;
u32 index;
struct zram *zram;
struct bio_vec bv;
zram = bdev->bd_disk->private_data;
+ if (unlikely(!zram_meta_get(zram)))
+ goto out;
+
if (!valid_io_request(zram, sector, PAGE_SIZE)) {
atomic64_inc(&zram->stats.invalid_io);
- return -EINVAL;
- }
-
- down_read(&zram->init_lock);
- if (unlikely(!init_done(zram))) {
- err = -EIO;
- goto out_unlock;
+ err = -EINVAL;
+ goto put_zram;
}
index = sector >> SECTORS_PER_PAGE_SHIFT;
@@ -964,8 +993,9 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector,
bv.bv_offset = 0;
err = zram_bvec_rw(zram, &bv, index, offset, rw);
-out_unlock:
- up_read(&zram->init_lock);
+put_zram:
+ zram_meta_put(zram);
+out:
/*
* If I/O fails, just return error(ie, non-zero) without
* calling page_endio.
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index b05a816b09ac..5249f51ccdb3 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -100,24 +100,26 @@ struct zram_meta {
struct zram {
struct zram_meta *meta;
+ struct zcomp *comp;
struct request_queue *queue;
struct gendisk *disk;
- struct zcomp *comp;
-
- /* Prevent concurrent execution of device init, reset and R/W request */
+ /* Prevent concurrent execution of device init */
struct rw_semaphore init_lock;
/*
- * This is the limit on amount of *uncompressed* worth of data
- * we can store in a disk.
+ * the number of pages zram can consume for storing compressed data
*/
- u64 disksize; /* bytes */
+ unsigned long limit_pages;
int max_comp_streams;
+
struct zram_stats stats;
+ atomic_t refcount; /* refcount for zram_meta */
+ /* wait all IO under all of cpu are done */
+ wait_queue_head_t io_done;
/*
- * the number of pages zram can consume for storing compressed data
+ * This is the limit on amount of *uncompressed* worth of data
+ * we can store in a disk.
*/
- unsigned long limit_pages;
-
+ u64 disksize; /* bytes */
char compressor[10];
};
#endif