On Thu, 2017-03-16 at 14:40 -0700, Himanshu Madhani wrote:
> +static int
> +scsi_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag)
> +
> +{
> + struct Scsi_Host *shost = hctx->driver_data;
> + struct request *req;
> + struct scsi_cmnd *cmd;
> +
> + req = blk_mq_tag_to_rq(shost->tag_set.tags[hctx->queue_num], tag);
> + if (!req)
> + return 0;
> +
> + cmd = blk_mq_rq_to_pdu(req);
> + if (!cmd)
> + return 0;
> +
> + if (shost->hostt->poll_queue)
> + return(shost->hostt->poll_queue(shost, cmd));
> + else return 0;
> +}
What will happen if the request with tag 'tag' is completed after the block
layer decided to call this function and before this function had the chance
to call blk_mq_tag_to_rq()? Will this trigger a kernel crash? Also, please
format patches properly. This is what checkpatch reports for this patch:
ERROR: code indent should use tabs where possible
#244: FILE: drivers/scsi/scsi_lib.c:2161:
+ struct Scsi_Host *shost = hctx->driver_data;$
WARNING: please, no spaces at the start of a line
#244: FILE: drivers/scsi/scsi_lib.c:2161:
+ struct Scsi_Host *shost = hctx->driver_data;$
ERROR: code indent should use tabs where possible
#245: FILE: drivers/scsi/scsi_lib.c:2162:
+ struct request *req;$
WARNING: please, no spaces at the start of a line
#245: FILE: drivers/scsi/scsi_lib.c:2162:
+ struct request *req;$
ERROR: code indent should use tabs where possible
#246: FILE: drivers/scsi/scsi_lib.c:2163:
+ struct scsi_cmnd *cmd;$
WARNING: please, no spaces at the start of a line
#246: FILE: drivers/scsi/scsi_lib.c:2163:
+ struct scsi_cmnd *cmd;$
ERROR: code indent should use tabs where possible
#248: FILE: drivers/scsi/scsi_lib.c:2165:
+ req = blk_mq_tag_to_rq(shost->tag_set.tags[hctx->queue_num], tag);$
WARNING: please, no spaces at the start of a line
#248: FILE: drivers/scsi/scsi_lib.c:2165:
+ req = blk_mq_tag_to_rq(shost->tag_set.tags[hctx->queue_num], tag);$
ERROR: code indent should use tabs where possible
#249: FILE: drivers/scsi/scsi_lib.c:2166:
+ if (!req)$
WARNING: please, no spaces at the start of a line
#249: FILE: drivers/scsi/scsi_lib.c:2166:
+ if (!req)$
ERROR: code indent should use tabs where possible
#250: FILE: drivers/scsi/scsi_lib.c:2167:
+ return 0;$
WARNING: please, no spaces at the start of a line
#250: FILE: drivers/scsi/scsi_lib.c:2167:
+ return 0;$
ERROR: code indent should use tabs where possible
#252: FILE: drivers/scsi/scsi_lib.c:2169:
+ cmd = blk_mq_rq_to_pdu(req);$
WARNING: please, no spaces at the start of a line
#252: FILE: drivers/scsi/scsi_lib.c:2169:
+ cmd = blk_mq_rq_to_pdu(req);$
ERROR: return is not a function, parentheses are not required
#257: FILE: drivers/scsi/scsi_lib.c:2174:
+ return(shost->hostt->poll_queue(shost, cmd));
ERROR: trailing statements should be on next line
#258: FILE: drivers/scsi/scsi_lib.c:2175:
+ else return 0;
WARNING: line over 80 characters
#262: FILE: drivers/scsi/scsi_lib.c:2179:
+__scsi_init_hctx(struct blk_mq_hw_ctx *hctx, struct Scsi_Host *shost, unsigned int hctx_idx)
WARNING: Unnecessary space before function pointer name
#306: FILE: include/scsi/scsi_host.h:139:
+ int (* poll_queue)(struct Scsi_Host *, struct scsi_cmnd *);
ERROR: space prohibited after that '*' (ctx:BxW)
#306: FILE: include/scsi/scsi_host.h:139:
+ int (* poll_queue)(struct Scsi_Host *, struct scsi_cmnd *);
^
Thanks,
Bart.
