allow userspace to modify scsi command filter on per device basis

This patch exports the per-gendisk command filter to user space through
sysfs, so it can be changed by the system administrator.
All users of the old cmd filter have been converted to use the new one.

Original patch from Peter Jones.

Signed-off-by: Adel Gadllah <adel.gadllah@gmail.com>
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

2 files changed, 18 insertions, 1 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d3ae9ad97213..a842b776d099 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -671,7 +671,6 @@ extern int blk_execute_rq(struct request_queue *, struct gendisk *,
                           struct request *, int);
 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
                                   struct request *, int, rq_end_io_fn *);
-extern int blk_verify_command(unsigned char *, int);
 extern void blk_unplug(struct request_queue *q);
 
 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
@@ -797,6 +796,15 @@ static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 
 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_register_filter(struct gendisk *disk);
+extern void blk_unregister_filter(struct gendisk *disk);
+
 #define MAX_PHYS_SEGMENTS 128
 #define MAX_HW_SEGMENTS 128
 #define SAFE_MAX_SECTORS 255
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 524ec96f5a23..e8787417f65a 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -110,6 +110,14 @@ 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 */
@@ -120,6 +128,7 @@ 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;