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, 13 insertions, 3 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index e61f22be4d0e..d2d34e2774b2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -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