diff options
author | Jerome Marchand <jmarchan@redhat.com> | 2011-09-06 13:02:11 (GMT) |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-09-06 23:56:15 (GMT) |
commit | 0900beae178a84e653d9088979cf3014babc097e (patch) | |
tree | c2ddc5d26f4f97e5406fede5cb391ec1296a1e62 /drivers/staging/zram | |
parent | a1c821ae6c63d9ac648374f4953295e350572d3c (diff) | |
download | linux-0900beae178a84e653d9088979cf3014babc097e.tar.xz |
staging: zram: fix zram locking
Currently init_lock only prevents concurrent execution of zram_init_device()
and zram_reset_device() but not zram_make_request() nor sysfs store functions.
This patch changes init_lock into a rw_semaphore. A write lock is taken by
init, reset and store functions, a read lock is taken by zram_make_request().
Also, avoids to release the lock before calling __zram_reset_device() for
cleaning after a failed init, thus preventing any concurrent task to see an
inconsistent state of zram.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/staging/zram')
-rw-r--r-- | drivers/staging/zram/zram_drv.c | 46 | ||||
-rw-r--r-- | drivers/staging/zram/zram_drv.h | 6 | ||||
-rw-r--r-- | drivers/staging/zram/zram_sysfs.c | 18 |
3 files changed, 44 insertions, 26 deletions
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index ec66b0a..6fb2be3 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -560,27 +560,34 @@ static int zram_make_request(struct request_queue *queue, struct bio *bio) { struct zram *zram = queue->queuedata; + if (unlikely(!zram->init_done) && zram_init_device(zram)) + goto error; + + down_read(&zram->init_lock); + if (unlikely(!zram->init_done)) + goto error_unlock; + if (!valid_io_request(zram, bio)) { zram_stat64_inc(zram, &zram->stats.invalid_io); - bio_io_error(bio); - return 0; - } - - if (unlikely(!zram->init_done) && zram_init_device(zram)) { - bio_io_error(bio); - return 0; + goto error_unlock; } __zram_make_request(zram, bio, bio_data_dir(bio)); + up_read(&zram->init_lock); return 0; + +error_unlock: + up_read(&zram->init_lock); +error: + bio_io_error(bio); + return 0; } -void zram_reset_device(struct zram *zram) +void __zram_reset_device(struct zram *zram) { size_t index; - mutex_lock(&zram->init_lock); zram->init_done = 0; /* Free various per-device buffers */ @@ -617,7 +624,13 @@ void zram_reset_device(struct zram *zram) memset(&zram->stats, 0, sizeof(zram->stats)); zram->disksize = 0; - mutex_unlock(&zram->init_lock); +} + +void zram_reset_device(struct zram *zram) +{ + down_write(&zram->init_lock); + __zram_reset_device(zram); + up_write(&zram->init_lock); } int zram_init_device(struct zram *zram) @@ -625,10 +638,10 @@ int zram_init_device(struct zram *zram) int ret; size_t num_pages; - mutex_lock(&zram->init_lock); + down_write(&zram->init_lock); if (zram->init_done) { - mutex_unlock(&zram->init_lock); + up_write(&zram->init_lock); return 0; } @@ -671,15 +684,14 @@ int zram_init_device(struct zram *zram) } zram->init_done = 1; - mutex_unlock(&zram->init_lock); + up_write(&zram->init_lock); pr_debug("Initialization done!\n"); return 0; fail: - mutex_unlock(&zram->init_lock); - zram_reset_device(zram); - + __zram_reset_device(zram); + up_write(&zram->init_lock); pr_err("Initialization failed: err=%d\n", ret); return ret; } @@ -703,7 +715,7 @@ static int create_device(struct zram *zram, int device_id) int ret = 0; init_rwsem(&zram->lock); - mutex_init(&zram->init_lock); + init_rwsem(&zram->init_lock); spin_lock_init(&zram->stat64_lock); zram->queue = blk_alloc_queue(GFP_KERNEL); diff --git a/drivers/staging/zram/zram_drv.h b/drivers/staging/zram/zram_drv.h index 59b01d6..7fdeb7d3 100644 --- a/drivers/staging/zram/zram_drv.h +++ b/drivers/staging/zram/zram_drv.h @@ -112,8 +112,8 @@ struct zram { struct request_queue *queue; struct gendisk *disk; int init_done; - /* Prevent concurrent execution of device init and reset */ - struct mutex init_lock; + /* Prevent concurrent execution of device init, reset and R/W request */ + struct rw_semaphore init_lock; /* * This is the limit on amount of *uncompressed* worth of data * we can store in a disk. @@ -130,6 +130,6 @@ extern struct attribute_group zram_disk_attr_group; #endif extern int zram_init_device(struct zram *zram); -extern void zram_reset_device(struct zram *zram); +extern void __zram_reset_device(struct zram *zram); #endif diff --git a/drivers/staging/zram/zram_sysfs.c b/drivers/staging/zram/zram_sysfs.c index df1f9dc..0ea8ed2 100644 --- a/drivers/staging/zram/zram_sysfs.c +++ b/drivers/staging/zram/zram_sysfs.c @@ -55,19 +55,23 @@ static ssize_t disksize_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { int ret; + u64 disksize; struct zram *zram = dev_to_zram(dev); + ret = strict_strtoull(buf, 10, &disksize); + if (ret) + return ret; + + down_write(&zram->init_lock); if (zram->init_done) { + up_write(&zram->init_lock); pr_info("Cannot change disksize for initialized device\n"); return -EBUSY; } - ret = strict_strtoull(buf, 10, &zram->disksize); - if (ret) - return ret; - - zram->disksize = PAGE_ALIGN(zram->disksize); + zram->disksize = PAGE_ALIGN(disksize); set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT); + up_write(&zram->init_lock); return len; } @@ -106,8 +110,10 @@ static ssize_t reset_store(struct device *dev, if (bdev) fsync_bdev(bdev); + down_write(&zram->init_lock); if (zram->init_done) - zram_reset_device(zram); + __zram_reset_device(zram); + up_write(&zram->init_lock); return len; } |