Commit 4a03d90e authored by Rusty Russell's avatar Rusty Russell Committed by James Bottomley
Browse files

[SCSI] BUG_ON() impossible condition in sg list counting



If blk_rq_map_sg wrote more than was allocated in the scatterlist,
BUG_ON() is probably the right thing to do.

[jejb: rejections fixed up]
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Acked-by: default avatarJens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent a8aae4d3
......@@ -1104,7 +1104,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
*
* Returns: 0 on success
* BLKPREP_DEFER if the failure is retryable
* BLKPREP_KILL if the failure is fatal
*/
static int scsi_init_io(struct scsi_cmnd *cmd)
{
......@@ -1138,17 +1137,9 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
* each segment.
*/
count = blk_rq_map_sg(req->q, req, cmd->request_buffer);
if (likely(count <= cmd->use_sg)) {
cmd->use_sg = count;
return BLKPREP_OK;
}
printk(KERN_ERR "Incorrect number of segments after building list\n");
printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg);
printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors,
req->current_nr_sectors);
return BLKPREP_KILL;
BUG_ON(count > cmd->use_sg);
cmd->use_sg = count;
return BLKPREP_OK;
}
static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
......
......@@ -368,14 +368,9 @@ static int scsi_tgt_init_cmd(struct scsi_cmnd *cmd, gfp_t gfp_mask)
dprintk("cmd %p cnt %d %lu\n", cmd, scsi_sg_count(cmd),
rq_data_dir(rq));
count = blk_rq_map_sg(rq->q, rq, scsi_sglist(cmd));
if (likely(count <= scsi_sg_count(cmd))) {
cmd->use_sg = count;
return 0;
}
eprintk("cmd %p cnt %d\n", cmd, scsi_sg_count(cmd));
scsi_free_sgtable(cmd);
return -EINVAL;
BUG_ON(count > cmd->use_sg);
cmd->use_sg = count;
return 0;
}
/* TODO: test this crap and replace bio_map_user with new interface maybe */
......
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