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block: move cmdfilter from gendisk to request_queue

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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>
This commit is contained in:
FUJITA Tomonori
2008-08-16 14:10:05 +09:00
committed by Jens Axboe
parent 1941246dd9
commit abf5439370
7 changed files with 132 additions and 163 deletions
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16
include/linux/blkdev.h
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@ -280,6 +280,15 @@ struct blk_queue_tag {
atomic_t refcnt; /* map can be shared */
};
#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 request_queue
{
/*
@ -398,6 +407,7 @@ struct request_queue
#if defined(CONFIG_BLK_DEV_BSG)
struct bsg_class_device bsg_dev;
#endif
struct blk_scsi_cmd_filter cmd_filter;
};
#define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
@ -833,11 +843,11 @@ extern int blkdev_issue_flush(struct block_device *, sector_t *);
/*
* command filter functions
*/
extern int blk_verify_command(struct file *file, unsigned char *cmd);
extern int blk_cmd_filter_verify_command(struct blk_scsi_cmd_filter *filter,
unsigned char *cmd, mode_t *f_mode);
extern int blk_verify_command(struct blk_scsi_cmd_filter *filter,
unsigned char *cmd, int has_write_perm);
extern int blk_register_filter(struct gendisk *disk);
extern void blk_unregister_filter(struct gendisk *disk);
extern void blk_set_cmd_filter_defaults(struct blk_scsi_cmd_filter *filter);
#define MAX_PHYS_SEGMENTS 128
#define MAX_HW_SEGMENTS 128