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Commit 68322984 authored by Christof Schmitt's avatar Christof Schmitt Committed by James Bottomley
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[SCSI] zfcp: Report scatter-gather limits to SCSI and block layer 



Instead of dealing with large segments in the scatter-gather lists in
zfcp_qdio.c, report the limits to the upper layers. With these limits
in place, the code for mapping large data blocks to multiple sbales
can be removed.

Reviewed-by: default avatarSwen Schillig <swen@vnet.ibm.com>
Signed-off-by: default avatarChristof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent 883c98fe

drivers/s390/scsi/zfcp_aux.c

+4 −0
Original line number Diff line number Diff line
@@ -545,6 +545,10 @@ struct zfcp_adapter *zfcp_adapter_enqueue(struct ccw_device *ccw_device) 
			       &zfcp_sysfs_adapter_attrs))

		goto failed;



	/* report size limit per scatter-gather segment */

	adapter->dma_parms.max_segment_size = ZFCP_QDIO_SBALE_LEN;

	adapter->ccw_device->dev.dma_parms = &adapter->dma_parms;



	if (!zfcp_adapter_scsi_register(adapter))

		return adapter;

drivers/s390/scsi/zfcp_def.h

+1 −0
Original line number Diff line number Diff line
@@ -205,6 +205,7 @@ struct zfcp_adapter { 
	struct work_struct	scan_work;

	struct service_level	service_level;

	struct workqueue_struct	*work_queue;

	struct device_dma_parameters dma_parms;

};



struct zfcp_port {

drivers/s390/scsi/zfcp_qdio.c

+11 −34
Original line number Diff line number Diff line
@@ -206,35 +206,6 @@ static void zfcp_qdio_undo_sbals(struct zfcp_qdio *qdio, 
	zfcp_qdio_zero_sbals(sbal, first, count);

}



static int zfcp_qdio_fill_sbals(struct zfcp_qdio *qdio,

				struct zfcp_qdio_req *q_req,

				unsigned int sbtype, void *start_addr,

				unsigned int total_length)

{

	struct qdio_buffer_element *sbale;

	unsigned long remaining, length;

	void *addr;



	/* split segment up */

	for (addr = start_addr, remaining = total_length; remaining > 0;

	     addr += length, remaining -= length) {

		sbale = zfcp_qdio_sbale_next(qdio, q_req, sbtype);

		if (!sbale) {

			atomic_inc(&qdio->req_q_full);

			zfcp_qdio_undo_sbals(qdio, q_req);

			return -EINVAL;

		}



		/* new piece must not exceed next page boundary */

		length = min(remaining,

			     (PAGE_SIZE - ((unsigned long)addr &

					   (PAGE_SIZE - 1))));

		sbale->addr = addr;

		sbale->length = length;

	}

	return 0;

}



/**

 * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list

 * @fsf_req: request to be processed
@@ -248,7 +219,7 @@ int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req, 
			    int max_sbals)

{

	struct qdio_buffer_element *sbale;

	int retval, bytes = 0;

	int bytes = 0;



	/* figure out last allowed SBAL */

	zfcp_qdio_sbal_limit(qdio, q_req, max_sbals);
@@ -258,10 +229,16 @@ int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req, 
	sbale->flags |= sbtype;



	for (; sg; sg = sg_next(sg)) {

		retval = zfcp_qdio_fill_sbals(qdio, q_req, sbtype,

					      sg_virt(sg), sg->length);

		if (retval < 0)

			return retval;

		sbale = zfcp_qdio_sbale_next(qdio, q_req, sbtype);

		if (!sbale) {

			atomic_inc(&qdio->req_q_full);

			zfcp_qdio_undo_sbals(qdio, q_req);

			return -EINVAL;

		}



		sbale->addr = sg_virt(sg);

		sbale->length = sg->length;



		bytes += sg->length;

	}

drivers/s390/scsi/zfcp_qdio.h

+2 −0
Original line number Diff line number Diff line
@@ -11,6 +11,8 @@ 


#include <asm/qdio.h>



#define ZFCP_QDIO_SBALE_LEN	PAGE_SIZE



/**

 * struct zfcp_qdio_queue - qdio queue buffer, zfcp index and free count

 * @sbal: qdio buffers

drivers/s390/scsi/zfcp_scsi.c

+1 −0
Original line number Diff line number Diff line
@@ -682,6 +682,7 @@ struct zfcp_data zfcp_data = { 
		.use_clustering		 = 1,

		.sdev_attrs		 = zfcp_sysfs_sdev_attrs,

		.max_sectors		 = (ZFCP_MAX_SBALES_PER_REQ * 8),

		.dma_boundary		 = ZFCP_QDIO_SBALE_LEN - 1,

		.shost_attrs		 = zfcp_sysfs_shost_attrs,

	},

};