Increasing the per-request size maximum to 4MiB (8192 sectors x 512 bytes)
runs into the per-device DMA scatter gather list limit (max_segments) for
users of the io vector system calls (e.g. readv and writev).
This change increases the max scatter gather list length to 1024 to enable
kernel to send 4MiB (1024 * 4KiB page size) requests.
Signed-off-by: Igor Pylypiv <ipylypiv@xxxxxxxxxx>
---
Changes since v1:
- Added .max_sectors = 8192 to pm8001 scsi host template.
- Defined page size, sector size, and max I/O size to calculate max_sectors
and sg_tablesize values.
drivers/scsi/pm8001/pm8001_defs.h | 7 +++++--
drivers/scsi/pm8001/pm8001_init.c | 1 +
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/pm8001/pm8001_defs.h b/drivers/scsi/pm8001/pm8001_defs.h
index 501b574239e8..7871e29a820a 100644
--- a/drivers/scsi/pm8001/pm8001_defs.h
+++ b/drivers/scsi/pm8001/pm8001_defs.h
@@ -92,8 +92,11 @@ enum port_type {
#define PM8001_MAX_MSIX_VEC 64 /* max msi-x int for spcv/ve */
#define PM8001_RESERVE_SLOT 8
-#define CONFIG_SCSI_PM8001_MAX_DMA_SG 528
-#define PM8001_MAX_DMA_SG CONFIG_SCSI_PM8001_MAX_DMA_SG
+#define PM8001_SECTOR_SIZE 512
+#define PM8001_PAGE_SIZE_4K 4096
+#define PM8001_MAX_IO_SIZE (4 * 1024 * 1024)
+#define PM8001_MAX_DMA_SG (PM8001_MAX_IO_SIZE / PM8001_PAGE_SIZE_4K)
+#define PM8001_MAX_SECTORS (PM8001_MAX_IO_SIZE / PM8001_SECTOR_SIZE)
enum memory_region_num {
AAP1 = 0x0, /* application acceleration processor */
diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
index 33e1eba62ca1..c87443b14ff7 100644
--- a/drivers/scsi/pm8001/pm8001_init.c
+++ b/drivers/scsi/pm8001/pm8001_init.c
@@ -117,6 +117,7 @@ static const struct scsi_host_template pm8001_sht = {
.scan_start = pm8001_scan_start,
.can_queue = 1,
.sg_tablesize = PM8001_MAX_DMA_SG,
+ .max_sectors = PM8001_MAX_SECTORS,
.shost_groups = pm8001_host_groups,
.sdev_groups = pm8001_sdev_groups,
.track_queue_depth = 1,
--
2.47.0.163.g1226f6d8fa-goog
