scsi: s390: zfcp_fc: use sg helper to iterate over scatterlist

Unlike the legacy I/O path, scsi-mq preallocates a large array to hold
the scatterlist for each request. This static allocation can consume
substantial amounts of memory on modern controllers which support a
large number of concurrently outstanding requests.

To facilitate a switch to a smaller static allocation combined with a
dynamic allocation for requests that need it, we need to make sure all
SCSI drivers handle chained scatterlists correctly.

Convert remaining drivers that directly dereference the scatterlist
array to using the iterator functions.

[mkp: clarified commit message]

Cc: Steffen Maier <[email protected]>
Cc: Benjamin Block <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: [email protected]
Acked-by: Benjamin Block <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Signed-off-by: Ming Lei <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/s390/scsi/zfcp_fc.c b/drivers/s390/scsi/zfcp_fc.c
index 33eddb02ee30..b018b61bd168 100644
--- a/drivers/s390/scsi/zfcp_fc.c
+++ b/drivers/s390/scsi/zfcp_fc.c
@@ -620,7 +620,7 @@ static void zfcp_fc_sg_free_table(struct scatterlist *sg, int count)
 {
 	int i;
 
-	for (i = 0; i < count; i++, sg++)
+	for (i = 0; i < count; i++, sg = sg_next(sg))
 		if (sg)
 			free_page((unsigned long) sg_virt(sg));
 		else
@@ -641,7 +641,7 @@ static int zfcp_fc_sg_setup_table(struct scatterlist *sg, int count)
 	int i;
 
 	sg_init_table(sg, count);
-	for (i = 0; i < count; i++, sg++) {
+	for (i = 0; i < count; i++, sg = sg_next(sg)) {
 		addr = (void *) get_zeroed_page(GFP_KERNEL);
 		if (!addr) {
 			zfcp_fc_sg_free_table(sg, i);