[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: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 1e6183a..abf33db 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -545,6 +545,10 @@
&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;
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index 7131c7d..72132c13 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -205,6 +205,7 @@
struct work_struct scan_work;
struct service_level service_level;
struct workqueue_struct *work_queue;
+ struct device_dma_parameters dma_parms;
};
struct zfcp_port {
diff --git a/drivers/s390/scsi/zfcp_qdio.c b/drivers/s390/scsi/zfcp_qdio.c
index dbfa312..aa68515 100644
--- a/drivers/s390/scsi/zfcp_qdio.c
+++ b/drivers/s390/scsi/zfcp_qdio.c
@@ -206,35 +206,6 @@
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 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 @@
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;
}
diff --git a/drivers/s390/scsi/zfcp_qdio.h b/drivers/s390/scsi/zfcp_qdio.h
index 8cca546..f2b5a36 100644
--- a/drivers/s390/scsi/zfcp_qdio.h
+++ b/drivers/s390/scsi/zfcp_qdio.h
@@ -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
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index d13eb9a..066b050 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -682,6 +682,7 @@
.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,
},
};