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authorSwen Schillig <swen@vnet.ibm.com>2010-07-16 15:37:37 +0200
committerJames Bottomley <James.Bottomley@suse.de>2010-07-28 09:48:49 -0500
commit01b047599ade30051bf6c14fbe64181d1fec3dfa (patch)
tree3a44039ec1c48b41ba8e988c230291aca20b833c /drivers/s390/scsi/zfcp_qdio.h
parentfaf4cd854203b26527d81e7e13d66e78774dad44 (diff)
[SCSI] zfcp: Cleanup function parameters for sbal value.
A lot of functions require the amount of SBALs as one of their parameter which is most times invariable. Therefore remove this parameter and set the SBAL value explicitly if a non standard value is required. In addition the warning message "oversized data" is replaced with a BUG_ON() statement assuring the limits defined and requested by zfcp. Signed-off-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>
Diffstat (limited to 'drivers/s390/scsi/zfcp_qdio.h')
-rw-r--r--drivers/s390/scsi/zfcp_qdio.h28
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/s390/scsi/zfcp_qdio.h b/drivers/s390/scsi/zfcp_qdio.h
index 138fba577b4..8bb00545f19 100644
--- a/drivers/s390/scsi/zfcp_qdio.h
+++ b/drivers/s390/scsi/zfcp_qdio.h
@@ -19,6 +19,14 @@
/* index of last SBALE (with respect to DMQ bug workaround) */
#define ZFCP_QDIO_LAST_SBALE_PER_SBAL (ZFCP_QDIO_MAX_SBALES_PER_SBAL - 1)
+/* Max SBALS for chaining */
+#define ZFCP_QDIO_MAX_SBALS_PER_REQ 36
+
+/* max. number of (data buffer) SBALEs in largest SBAL chain
+ * request ID + QTCB in SBALE 0 + 1 of first SBAL in chain */
+#define ZFCP_QDIO_MAX_SBALES_PER_REQ \
+ (ZFCP_QDIO_MAX_SBALS_PER_REQ * ZFCP_QDIO_MAX_SBALES_PER_SBAL - 2)
+
/**
* struct zfcp_qdio_queue - qdio queue buffer, zfcp index and free count
* @sbal: qdio buffers
@@ -134,10 +142,14 @@ void zfcp_qdio_req_init(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
unsigned long req_id, u32 sbtype, void *data, u32 len)
{
struct qdio_buffer_element *sbale;
+ int count = min(atomic_read(&qdio->req_q.count),
+ ZFCP_QDIO_MAX_SBALS_PER_REQ);
q_req->sbal_first = q_req->sbal_last = qdio->req_q.first;
q_req->sbal_number = 1;
q_req->sbtype = sbtype;
+ q_req->sbal_limit = (q_req->sbal_first + count - 1)
+ % QDIO_MAX_BUFFERS_PER_Q;
sbale = zfcp_qdio_sbale_req(qdio, q_req);
sbale->addr = (void *) req_id;
@@ -210,4 +222,20 @@ void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio_req *q_req)
q_req->sbale_curr = ZFCP_QDIO_LAST_SBALE_PER_SBAL;
}
+/**
+ * zfcp_qdio_sbal_limit - set the sbal limit for a request in q_req
+ * @qdio: pointer to struct zfcp_qdio
+ * @q_req: The current zfcp_qdio_req
+ * @max_sbals: maximum number of SBALs allowed
+ */
+static inline
+void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,
+ struct zfcp_qdio_req *q_req, int max_sbals)
+{
+ int count = min(atomic_read(&qdio->req_q.count), max_sbals);
+
+ q_req->sbal_limit = (q_req->sbal_first + count - 1) %
+ QDIO_MAX_BUFFERS_PER_Q;
+}
+
#endif /* ZFCP_QDIO_H */