block: move cmdfilter from gendisk to request_queue

cmd_filter works only for the block layer SG_IO with SCSI block
devices. It breaks scsi/sg.c, bsg, and the block layer SG_IO with SCSI
character devices (such as st). We hit a kernel crash with them.

The problem is that cmd_filter code accesses to gendisk (having struct
blk_scsi_cmd_filter) via inode->i_bdev->bd_disk. It works for only
SCSI block device files. With character device files, inode->i_bdev
leads you to struct cdev. inode->i_bdev->bd_disk->blk_scsi_cmd_filter
isn't safe.

SCSI ULDs don't expose gendisk; they keep it private. bsg needs to be
independent on any protocols. We shouldn't change ULDs to expose their
gendisk.

This patch moves struct blk_scsi_cmd_filter from gendisk to
request_queue, a common object, which eveyone can access to.

The user interface doesn't change; users can change the filters via
/sys/block/. gendisk has a pointer to request_queue so the cmd_filter
code accesses to struct blk_scsi_cmd_filter.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 0 insertions, 10 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 118216f..be4f5e5 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -110,15 +110,6 @@ struct hd_struct {
 #define GENHD_FL_SUPPRESS_PARTITION_INFO	32
 #define GENHD_FL_FAIL				64
 
-#define BLK_SCSI_MAX_CMDS	(256)
-#define BLK_SCSI_CMD_PER_LONG	(BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
-
-struct blk_scsi_cmd_filter {
-	unsigned long read_ok[BLK_SCSI_CMD_PER_LONG];
-	unsigned long write_ok[BLK_SCSI_CMD_PER_LONG];
-	struct kobject kobj;
-};
-
 struct gendisk {
 	int major;			/* major number of driver */
 	int first_minor;
@@ -128,7 +119,6 @@ struct gendisk {
 	struct hd_struct **part;	/* [indexed by minor] */
 	struct block_device_operations *fops;
 	struct request_queue *queue;
-	struct blk_scsi_cmd_filter cmd_filter;
 	void *private_data;
 	sector_t capacity;