[SCSI] add support for per-host cmd pools
This allows drivers to specify the size of their per-command private
data in the host template and then get extra memory allocated for
each command instead of needing another allocation in ->queuecommand.
With the current SCSI code that already does multiple allocations for
each command this probably doesn't make a big performance impact, but
it allows to clean up the drivers, and prepare them for using the
blk-mq infrastructure where the common allocation will make a difference.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 53075e5..94844fc 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -15,6 +15,7 @@
struct module;
struct scsi_cmnd;
struct scsi_device;
+struct scsi_host_cmd_pool;
struct scsi_target;
struct Scsi_Host;
struct scsi_host_cmd_pool;
@@ -524,6 +525,12 @@
* scsi_netlink.h
*/
u64 vendor_id;
+
+ /*
+ * Additional per-command data allocated for the driver.
+ */
+ unsigned int cmd_size;
+ struct scsi_host_cmd_pool *cmd_pool;
};
/*