When we wrote data to an SATA HDD, the following timeout issue
happened after the commit 429120f3df2d ("block: fix splitting
segments on boundary masks") was applied:
# dd if=/dev/urandom of=/mnt/de1/file1-1024M bs=1M count=1024
ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
ata1.00: failed command: WRITE DMA EXT
ata1.00: cmd 35/00:00:00:e6:0c/00:0a:00:00:00/e0 tag 0 dma 1310720 out
res 40/00:01:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
ata1.00: status: { DRDY }
Since the commit changed get_max_segment_size()'s behavior,
unexpected behavior happens if .dma_boundary of this sata-rcar driver
is 0x1ffffffe in somewhere (my guess).
By the way, the commit 8bfbeed58665 ("sata_rcar: correct
'sata_rcar_sht'") changed the .dma_boundary as 0x1ffffffe, but this
number is related to ATAPI_DMA_TRANS_CNT register. So, we should set
the .dma_boundary as ATA_DMA_BOUNDARY (0xffff), and set
.max_segment_size to min(0x1ffffffe, dma_max_mapping_size()).
After applied this, the timeout issue disappeared.
Fixes: 8bfbeed58665 ("sata_rcar: correct 'sata_rcar_sht'")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
---
As I wrote the commit description, I couldn't find why the issue
was related to the .dma_boundary. So, I marked RFC on this patch.
I would appreciate it if you would give me some advice.
drivers/ata/sata_rcar.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/drivers/ata/sata_rcar.c b/drivers/ata/sata_rcar.c
index 141ac60..abd0752 100644
--- a/drivers/ata/sata_rcar.c
+++ b/drivers/ata/sata_rcar.c
@@ -120,7 +120,7 @@
/* Descriptor table word 0 bit (when DTA32M = 1) */
#define SATA_RCAR_DTEND BIT(0)
-#define SATA_RCAR_DMA_BOUNDARY 0x1FFFFFFEUL
+#define SATA_RCAR_DMA_TRANS_CNT 0x1FFFFFFEUL
/* Gen2 Physical Layer Control Registers */
#define RCAR_GEN2_PHY_CTL1_REG 0x1704
@@ -636,14 +636,7 @@ static u8 sata_rcar_bmdma_status(struct ata_port *ap)
}
static struct scsi_host_template sata_rcar_sht = {
- ATA_BASE_SHT(DRV_NAME),
- /*
- * This controller allows transfer chunks up to 512MB which cross 64KB
- * boundaries, therefore the DMA limits are more relaxed than standard
- * ATA SFF.
- */
- .sg_tablesize = ATA_MAX_PRD,
- .dma_boundary = SATA_RCAR_DMA_BOUNDARY,
+ ATA_BMDMA_SHT(DRV_NAME),
};
static struct ata_port_operations sata_rcar_port_ops = {
@@ -930,6 +923,14 @@ static int sata_rcar_probe(struct platform_device *pdev)
/* initialize host controller */
sata_rcar_init_controller(host);
+ /*
+ * This controller allows transfer chunks up to 512MB which cross 64KB
+ * boundaries, therefore the DMA limits are more relaxed than standard
+ * ATA SFF.
+ */
+ sata_rcar_sht.max_segment_size = min_t(unsigned int,
+ SATA_RCAR_DMA_TRANS_CNT,
+ dma_max_mapping_size(dev));
ret = ata_host_activate(host, irq, sata_rcar_interrupt, 0,
&sata_rcar_sht);
if (!ret)
--
2.7.4
