[PATCH v3 08/17] dmaengine: bcm-sba-raid: Increase number of free sba_request

From: Anup Patel
Date: Tue Aug 22 2017 - 05:58:27 EST


Currently, we have only 1024 free sba_request created
by sba_prealloc_channel_resources(). This is too low
and the prep_xxx() callbacks start failing more often
at time of RAID array setup over NVMe disks.

This patch sets number of free sba_request created by
sba_prealloc_channel_resources() to be:
<number_of_mailbox_channels> x 8192

Due to above, we will have sufficient number of free
sba_request and prep_xxx() callbacks failing is very
unlikely.

Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxxxx>
---
drivers/dma/bcm-sba-raid.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/dma/bcm-sba-raid.c b/drivers/dma/bcm-sba-raid.c
index cd6e3cd..af6cc8e 100644
--- a/drivers/dma/bcm-sba-raid.c
+++ b/drivers/dma/bcm-sba-raid.c
@@ -83,6 +83,8 @@
#define SBA_CMD_WRITE_BUFFER 0xc
#define SBA_CMD_GALOIS 0xe

+#define SBA_MAX_REQ_PER_MBOX_CHANNEL 8192
+
/* Driver helper macros */
#define to_sba_request(tx) \
container_of(tx, struct sba_request, tx)
@@ -1622,6 +1624,13 @@ static int sba_probe(struct platform_device *pdev)
sba->dev = &pdev->dev;
platform_set_drvdata(pdev, sba);

+ /* Number of channels equals number of mailbox channels */
+ ret = of_count_phandle_with_args(pdev->dev.of_node,
+ "mboxes", "#mbox-cells");
+ if (ret <= 0)
+ return -ENODEV;
+ mchans_count = ret;
+
/* Determine SBA version from DT compatible string */
if (of_device_is_compatible(sba->dev->of_node, "brcm,iproc-sba"))
sba->ver = SBA_VER_1;
@@ -1634,14 +1643,12 @@ static int sba_probe(struct platform_device *pdev)
/* Derived Configuration parameters */
switch (sba->ver) {
case SBA_VER_1:
- sba->max_req = 1024;
sba->hw_buf_size = 4096;
sba->hw_resp_size = 8;
sba->max_pq_coefs = 6;
sba->max_pq_srcs = 6;
break;
case SBA_VER_2:
- sba->max_req = 1024;
sba->hw_buf_size = 4096;
sba->hw_resp_size = 8;
sba->max_pq_coefs = 30;
@@ -1655,6 +1662,7 @@ static int sba_probe(struct platform_device *pdev)
default:
return -EINVAL;
}
+ sba->max_req = SBA_MAX_REQ_PER_MBOX_CHANNEL * mchans_count;
sba->max_cmd_per_req = sba->max_pq_srcs + 3;
sba->max_xor_srcs = sba->max_cmd_per_req - 1;
sba->max_resp_pool_size = sba->max_req * sba->hw_resp_size;
@@ -1668,22 +1676,14 @@ static int sba_probe(struct platform_device *pdev)
sba->client.knows_txdone = false;
sba->client.tx_tout = 0;

- /* Number of channels equals number of mailbox channels */
- ret = of_count_phandle_with_args(pdev->dev.of_node,
- "mboxes", "#mbox-cells");
- if (ret <= 0)
- return -ENODEV;
- mchans_count = ret;
- sba->mchans_count = 0;
- atomic_set(&sba->mchans_current, 0);
-
/* Allocate mailbox channel array */
- sba->mchans = devm_kcalloc(&pdev->dev, sba->mchans_count,
+ sba->mchans = devm_kcalloc(&pdev->dev, mchans_count,
sizeof(*sba->mchans), GFP_KERNEL);
if (!sba->mchans)
return -ENOMEM;

/* Request mailbox channels */
+ sba->mchans_count = 0;
for (i = 0; i < mchans_count; i++) {
sba->mchans[i] = mbox_request_channel(&sba->client, i);
if (IS_ERR(sba->mchans[i])) {
@@ -1692,6 +1692,7 @@ static int sba_probe(struct platform_device *pdev)
}
sba->mchans_count++;
}
+ atomic_set(&sba->mchans_current, 0);

/* Find-out underlying mailbox device */
ret = of_parse_phandle_with_args(pdev->dev.of_node,
--
2.7.4