[PATCH 1/3] ntb_perf: Allow limiting the size of the memory windows

[Logan Gunthorpe]

On my system, dma_alloc_coherent won't produce memory anywhere
near the size of the BAR. So I needed a way to limit this.

It's pretty much copied straight from ntb_transport.

Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
---
drivers/ntb/test/ntb_perf.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/ntb/test/ntb_perf.c b/drivers/ntb/test/ntb_perf.c
index 8dfce9c..30635c8 100644
--- a/drivers/ntb/test/ntb_perf.c
+++ b/drivers/ntb/test/ntb_perf.c
@@ -83,6 +83,10 @@ MODULE_DESCRIPTION(DRIVER_DESCRIPTION);

static struct dentry *perf_debugfs_dir;

+static unsigned long max_mw_size;
+module_param(max_mw_size, ulong, 0644);
+MODULE_PARM_DESC(max_mw_size, "Limit size of large memory windows");
+
static unsigned int seg_order = 19; /* 512K */
module_param(seg_order, uint, 0644);
MODULE_PARM_DESC(seg_order, "size order [n^2] of buffer segment for testing");
@@ -472,6 +476,10 @@ static void perf_link_work(struct work_struct *work)
dev_dbg(&perf->ntb->pdev->dev, "%s called\n", __func__);

size = perf->mw.phys_size;
+
+ if (max_mw_size && size > max_mw_size)
+ size = max_mw_size;
+
ntb_peer_spad_write(ndev, MW_SZ_HIGH, upper_32_bits(size));
ntb_peer_spad_write(ndev, MW_SZ_LOW, lower_32_bits(size));
ntb_peer_spad_write(ndev, VERSION, PERF_VERSION);
--
2.1.4

[Logan Gunthorpe]

Hi,

I've been working on developing an experimental NTB driver for some
custom hardware and I've found the need to make some minor enhancements
to the NTB layer.

1) I've modified ntb_perf to take an option similar to ntb_transport
which limits the memory window size. This was useful seeing the mws
I'm dealing with are much larger than the available coherent memory I
can allocate.

2) I've added code to ntb_perf and ntb_transport to check that there
are enough scratchpad registers. (As I was hit by a problem where my
hardware did not have enough for ntb_transport, and I would have liked
better information on the cause of the issue.)

3) Added support to debug and test memory windows to ntb_tool. A
coherent buffer is added when the link comes up, and then a debugfs
file for each mw and peer mw is added which allows reading and writing
the buffer. This was useful for me to debug window alignment issues I
was having.

I'm happy to make any revisions to these patches if anyone finds any
issues.

Thanks,

Logan


Logan Gunthorpe (3):
ntb_perf: Allow limiting the size of the memory windows
ntb_transport: Check the number of spads the hardware supports
ntb_tool: Add memory window debug support

drivers/ntb/ntb_transport.c | 9 +-
drivers/ntb/test/ntb_perf.c | 16 ++-
drivers/ntb/test/ntb_tool.c | 258 +++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 278 insertions(+), 5 deletions(-)

--
2.1.4

[Logan Gunthorpe]

We allocate some memory window buffers when the link comes up, then we
provide debugfs files to read/write each side of the link.

This is useful for debugging the mapping when writing new drivers.

Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
---

drivers/ntb/test/ntb_tool.c | 258 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 257 insertions(+), 1 deletion(-)

diff --git a/drivers/ntb/test/ntb_tool.c b/drivers/ntb/test/ntb_tool.c
index 209ef7c..4c01057 100644
--- a/drivers/ntb/test/ntb_tool.c
+++ b/drivers/ntb/test/ntb_tool.c
@@ -89,6 +89,7 @@
#include <linux/dma-mapping.h>
#include <linux/pci.h>
#include <linux/slab.h>
+#include <linux/uaccess.h>

#include <linux/ntb.h>

@@ -105,11 +106,29 @@ MODULE_VERSION(DRIVER_VERSION);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESCRIPTION);

+#define MAX_MWS 16
+
+static unsigned long mw_size = 16;
+module_param(mw_size, ulong, 0644);
+MODULE_PARM_DESC(mw_size, "size order [n^2] of the memory window for testing");
+
static struct dentry *tool_dbgfs;

+struct tool_mw {
+ resource_size_t size;
+ u8 __iomem *local;
+ u8 *peer;
+ dma_addr_t peer_dma;
+};
+
struct tool_ctx {
struct ntb_dev *ntb;
struct dentry *dbgfs;
+ struct work_struct link_cleanup;
+ bool link_is_up;
+ struct delayed_work link_work;
+ int mw_count;
+ struct tool_mw mws[MAX_MWS];
};

#define SPAD_FNAME_SIZE 0x10
@@ -124,6 +143,111 @@ struct tool_ctx {
.write = __write, \
}

+static int tool_setup_mw(struct tool_ctx *tc, int idx)
+{
+ int rc;
+ struct tool_mw *mw = &tc->mws[idx];
+ phys_addr_t base;
+ resource_size_t size, align, align_size;
+
+ if (mw->local)
+ return 0;
+
+ rc = ntb_mw_get_range(tc->ntb, idx, &base, &size, &align,
+ &align_size);
+ if (rc)
+ return rc;
+
+ mw->size = min_t(resource_size_t, 1 << mw_size, size);
+ mw->size = round_up(mw->size, align);
+ mw->size = round_up(mw->size, align_size);
+
+ mw->local = ioremap_wc(base, size);
+ if (mw->local == NULL)
+ return -EFAULT;
+
+ mw->peer = dma_alloc_coherent(&tc->ntb->pdev->dev, mw->size,
+ &mw->peer_dma, GFP_KERNEL);
+
+ if (mw->peer == NULL)
+ return -ENOMEM;
+
+ rc = ntb_mw_set_trans(tc->ntb, idx, mw->peer_dma, mw->size);
+ if (rc)
+ return rc;
+
+ return 0;
+}
+
+static void tool_free_mws(struct tool_ctx *tc)
+{
+ int i;
+
+ for (i = 0; i < tc->mw_count; i++) {
+ if (tc->mws[i].peer) {
+ ntb_mw_clear_trans(tc->ntb, i);
+ dma_free_coherent(&tc->ntb->pdev->dev, tc->mws[i].size,
+ tc->mws[i].peer,
+ tc->mws[i].peer_dma);
+
+ }
+
+ tc->mws[i].peer = NULL;
+ tc->mws[i].peer_dma = 0;
+
+ if (tc->mws[i].local)
+ iounmap(tc->mws[i].local);
+
+ tc->mws[i].local = NULL;
+ }
+
+ tc->mw_count = 0;
+}
+
+static int tool_setup_mws(struct tool_ctx *tc)
+{
+ int i;
+ int rc;
+
+ tc->mw_count = min(ntb_mw_count(tc->ntb), MAX_MWS);
+
+ for (i = 0; i < tc->mw_count; i++) {
+ rc = tool_setup_mw(tc, i);
+ if (rc)
+ goto err_out;
+ }
+
+ return 0;
+
+err_out:
+ tool_free_mws(tc);
+ return rc;
+}
+
+static void tool_link_work(struct work_struct *work)
+{
+ int rc;
+ struct tool_ctx *tc = container_of(work, struct tool_ctx,
+ link_work.work);
+
+ tool_free_mws(tc);
+ rc = tool_setup_mws(tc);
+ if (rc)
+ dev_err(&tc->ntb->dev,
+ "Error setting up memory windows: %d\n", rc);
+
+ tc->link_is_up = true;
+}
+
+static void tool_link_cleanup(struct work_struct *work)
+{
+ struct tool_ctx *tc = container_of(work, struct tool_ctx,
+ link_cleanup);
+
+ if (!tc->link_is_up)
+ cancel_delayed_work_sync(&tc->link_work);
+}
+
static void tool_link_event(void *ctx)
{
struct tool_ctx *tc = ctx;
@@ -135,6 +259,11 @@ static void tool_link_event(void *ctx)

dev_dbg(&tc->ntb->dev, "link is %s speed %d width %d\n",
up ? "up" : "down", speed, width);
+
+ if (up)
+ schedule_delayed_work(&tc->link_work, 2*HZ);
+ else
+ schedule_work(&tc->link_cleanup);
}

static void tool_db_event(void *ctx, int vec)
@@ -443,8 +572,112 @@ static TOOL_FOPS_RDWR(tool_peer_spad_fops,
tool_peer_spad_read,
tool_peer_spad_write);

+
+static ssize_t tool_mw_read(struct file *filep, char __user *ubuf,
+ size_t size, loff_t *offp)
+{
+ struct tool_mw *mw = filep->private_data;
+ ssize_t rc;
+ loff_t pos = *offp;
+ void *buf;
+
+ if (mw->local == NULL)
+ return -EIO;
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= mw->size || !size)
+ return 0;
+ if (size > mw->size - pos)
+ size = mw->size - pos;
+
+ buf = kmalloc(size, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ memcpy_fromio(buf, mw->local + pos, size);
+ rc = copy_to_user(ubuf, buf, size);
+ if (rc == size) {
+ rc = -EFAULT;
+ goto err_free;
+ }
+
+ size -= rc;
+ *offp = pos + size;
+ rc = size;
+
+err_free:
+ kfree(buf);
+
+ return rc;
+}
+
+static ssize_t tool_mw_write(struct file *filep, const char __user *ubuf,
+ size_t size, loff_t *offp)
+{
+ struct tool_mw *mw = filep->private_data;
+ ssize_t rc;
+ loff_t pos = *offp;
+ void *buf;
+
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= mw->size || !size)
+ return 0;
+ if (size > mw->size - pos)
+ size = mw->size - pos;
+
+ buf = kmalloc(size, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ rc = copy_from_user(buf, ubuf, size);
+ if (rc == size) {
+ rc = -EFAULT;
+ goto err_free;
+ }
+
+ size -= rc;
+ *offp = pos + size;
+ rc = size;
+
+ memcpy_toio(mw->local + pos, buf, size);
+
+err_free:
+ kfree(buf);
+
+ return rc;
+}
+
+static TOOL_FOPS_RDWR(tool_mw_fops,
+ tool_mw_read,
+ tool_mw_write);
+
+
+static ssize_t tool_peer_mw_read(struct file *filep, char __user *ubuf,
+ size_t size, loff_t *offp)
+{
+ struct tool_mw *mw = filep->private_data;
+
+ return simple_read_from_buffer(ubuf, size, offp, mw->peer, mw->size);
+}
+
+static ssize_t tool_peer_mw_write(struct file *filep, const char __user *ubuf,
+ size_t size, loff_t *offp)
+{
+ struct tool_mw *mw = filep->private_data;
+
+ return simple_write_to_buffer(mw->peer, mw->size, offp, ubuf, size);
+}
+
+static TOOL_FOPS_RDWR(tool_peer_mw_fops,
+ tool_peer_mw_read,
+ tool_peer_mw_write);
+
static void tool_setup_dbgfs(struct tool_ctx *tc)
{
+ int mw_count;
+ int i;
+
/* This modules is useless without dbgfs... */
if (!tool_dbgfs) {
tc->dbgfs = NULL;
@@ -473,6 +706,20 @@ static void tool_setup_dbgfs(struct tool_ctx *tc)

debugfs_create_file("peer_spad", S_IRUSR | S_IWUSR, tc->dbgfs,
tc, &tool_peer_spad_fops);
+
+ mw_count = min(ntb_mw_count(tc->ntb), MAX_MWS);
+ for (i = 0; i < mw_count; i++) {
+ char buf[30];
+
+ snprintf(buf, sizeof(buf), "mw%d", i);
+ debugfs_create_file(buf, S_IRUSR | S_IWUSR, tc->dbgfs,
+ &tc->mws[i], &tool_mw_fops);
+
+ snprintf(buf, sizeof(buf), "peer_mw%d", i);
+ debugfs_create_file(buf, S_IRUSR | S_IWUSR, tc->dbgfs,
+ &tc->mws[i], &tool_peer_mw_fops);
+
+ }
}

static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
@@ -486,13 +733,15 @@ static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
if (ntb_spad_is_unsafe(ntb))
dev_dbg(&ntb->dev, "scratchpad is unsafe\n");

- tc = kmalloc(sizeof(*tc), GFP_KERNEL);
+ tc = kzalloc(sizeof(*tc), GFP_KERNEL);
if (!tc) {
rc = -ENOMEM;
goto err_tc;
}

tc->ntb = ntb;
+ INIT_DELAYED_WORK(&tc->link_work, tool_link_work);
+ INIT_WORK(&tc->link_cleanup, tool_link_cleanup);

tool_setup_dbgfs(tc);

@@ -507,6 +756,8 @@ static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)

err_ctx:
debugfs_remove_recursive(tc->dbgfs);
+ cancel_delayed_work_sync(&tc->link_work);
+ cancel_work_sync(&tc->link_cleanup);
kfree(tc);
err_tc:
return rc;
@@ -516,6 +767,11 @@ static void tool_remove(struct ntb_client *self, struct ntb_dev *ntb)
{
struct tool_ctx *tc = ntb->ctx;

+ cancel_delayed_work_sync(&tc->link_work);
+ cancel_work_sync(&tc->link_cleanup);
+
+ tool_free_mws(tc);
+
ntb_clear_ctx(ntb);
ntb_link_disable(ntb);

--
2.1.4

[Logan Gunthorpe]

I'm working on hardware that currently has a limited number of
scratchpad registers and ntb_ndev fails with no clue as to why. I
feel it is better to fail early and provide a reasonable error message
then to fail later on..

The same is done to ntb_perf, but it doesn't currently require enough
spads to actually fail.

Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
---

drivers/ntb/ntb_transport.c | 9 +++++++--
drivers/ntb/test/ntb_perf.c | 8 ++++++--
2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 2ef9d913..34e7a7a 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -1037,6 +1037,13 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
int node;
int rc, i;

+ mw_count = ntb_mw_count(ndev);
+ if (ntb_spad_count(ndev) < (NUM_MWS + 1 + mw_count*2)) {
+ dev_err(&ndev->dev, "Not enough scratch pad registers for %s",
+ NTB_TRANSPORT_NAME);
+ return -EIO;
+ }
+
if (ntb_db_is_unsafe(ndev))
dev_dbg(&ndev->dev,
"doorbell is unsafe, proceed anyway...\n");
@@ -1052,8 +1059,6 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)

nt->ndev = ndev;

- mw_count = ntb_mw_count(ndev);
-
nt->mw_count = mw_count;

nt->mw_vec = kzalloc_node(mw_count * sizeof(*nt->mw_vec),
diff --git a/drivers/ntb/test/ntb_perf.c b/drivers/ntb/test/ntb_perf.c
index 30635c8..1815592 100644
--- a/drivers/ntb/test/ntb_perf.c
+++ b/drivers/ntb/test/ntb_perf.c
@@ -143,8 +143,6 @@ enum {
VERSION = 0,
MW_SZ_HIGH,
MW_SZ_LOW,
- SPAD_MSG,
- SPAD_ACK,
MAX_SPAD
};

@@ -698,6 +696,12 @@ static int perf_probe(struct ntb_client *client, struct ntb_dev *ntb)

node = dev_to_node(&pdev->dev);

+ if (ntb_spad_count(ntb) < MAX_SPAD) {
+ dev_err(&ntb->dev, "Not enough scratch pad registers for %s",
+ DRIVER_NAME);
+ return -EIO;
+ }
+
perf = kzalloc_node(sizeof(*perf), GFP_KERNEL, node);
if (!perf) {
rc = -ENOMEM;
--
2.1.4

[Jiang, Dave]

On Fri, 2016-06-03 at 14:50 -0600, Logan Gunthorpe wrote:
> On my system, dma_alloc_coherent won't produce memory anywhere
> near the size of the BAR. So I needed a way to limit this.
>
> It's pretty much copied straight from ntb_transport.
>
> Signed-off-by: Logan Gunthorpe <log...@deltatee.com>

Acked-by: Dave Jiang <dave....@intel.com>

[Allen Hubbe]

From: Logan Gunthorpe

> We allocate some memory window buffers when the link comes up, then we
> provide debugfs files to read/write each side of the link.
>
> This is useful for debugging the mapping when writing new drivers.
>
> Signed-off-by: Logan Gunthorpe <log...@deltatee.com>

Thanks! This was on my wish list.

Acked-by: Allen Hubbe <Allen...@emc.com>

[Jon Mason]

On Fri, Jun 3, 2016 at 5:03 PM, Jiang, Dave <dave....@intel.com> wrote:
> On Fri, 2016-06-03 at 14:50 -0600, Logan Gunthorpe wrote:
>> On my system, dma_alloc_coherent won't produce memory anywhere
>> near the size of the BAR. So I needed a way to limit this.
>>
>> It's pretty much copied straight from ntb_transport.
>>
>> Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
> Acked-by: Dave Jiang <dave....@intel.com>

Applied to my ntb-next branch

Thanks,
Jon

[Jon Mason]

On Fri, Jun 3, 2016 at 5:20 PM, Allen Hubbe <Allen...@emc.com> wrote:
> From: Logan Gunthorpe
>> We allocate some memory window buffers when the link comes up, then we
>> provide debugfs files to read/write each side of the link.
>>
>> This is useful for debugging the mapping when writing new drivers.
>>
>> Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
>
> Thanks! This was on my wish list.
>
> Acked-by: Allen Hubbe <Allen...@emc.com>

Applied to my ntb-next branch

Thanks,
Jon

[Jon Mason]

On Fri, Jun 03, 2016 at 02:50:32PM -0600, Logan Gunthorpe wrote:
> I'm working on hardware that currently has a limited number of
> scratchpad registers and ntb_ndev fails with no clue as to why. I
> feel it is better to fail early and provide a reasonable error message
> then to fail later on..
>
> The same is done to ntb_perf, but it doesn't currently require enough
> spads to actually fail.
>
> Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
> ---
> drivers/ntb/ntb_transport.c | 9 +++++++--
> drivers/ntb/test/ntb_perf.c | 8 ++++++--
> 2 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
> index 2ef9d913..34e7a7a 100644
> --- a/drivers/ntb/ntb_transport.c
> +++ b/drivers/ntb/ntb_transport.c
> @@ -1037,6 +1037,13 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
> int node;
> int rc, i;
>
> + mw_count = ntb_mw_count(ndev);
> + if (ntb_spad_count(ndev) < (NUM_MWS + 1 + mw_count*2)) {

Nit, please add spaces around '*' (per checkpatch)

> + dev_err(&ndev->dev, "Not enough scratch pad registers for %s",
> + NTB_TRANSPORT_NAME);
> + return -EIO;
> + }
> +
> if (ntb_db_is_unsafe(ndev))
> dev_dbg(&ndev->dev,
> "doorbell is unsafe, proceed anyway...\n");
> @@ -1052,8 +1059,6 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
>
> nt->ndev = ndev;
>
> - mw_count = ntb_mw_count(ndev);
> -
> nt->mw_count = mw_count;
>
> nt->mw_vec = kzalloc_node(mw_count * sizeof(*nt->mw_vec),
> diff --git a/drivers/ntb/test/ntb_perf.c b/drivers/ntb/test/ntb_perf.c
> index 30635c8..1815592 100644
> --- a/drivers/ntb/test/ntb_perf.c
> +++ b/drivers/ntb/test/ntb_perf.c
> @@ -143,8 +143,6 @@ enum {
> VERSION = 0,
> MW_SZ_HIGH,
> MW_SZ_LOW,
> - SPAD_MSG,
> - SPAD_ACK,

Please explicitly point out that this is being modified in the commit
message. I don't see them being used, so probably not a big deal
(unless Dave Jiang has something queued that will use it).

> MAX_SPAD
> };
>
> @@ -698,6 +696,12 @@ static int perf_probe(struct ntb_client *client, struct ntb_dev *ntb)
>
> node = dev_to_node(&pdev->dev);
>
> + if (ntb_spad_count(ntb) < MAX_SPAD) {
> + dev_err(&ntb->dev, "Not enough scratch pad registers for %s",
> + DRIVER_NAME);
> + return -EIO;
> + }

Move this check above the dev_to_node assignment above.

Thanks,
Jon

[Logan Gunthorpe]

Hi Jon,

Thanks for the feedback. I'll send an updated patch in a moment.

On 04/06/16 09:40 AM, Jon Mason wrote:
> Nit, please add spaces around '*' (per checkpatch)

I'll change this, but I did run it through checkpatch and it did not
warn about this.

> Please explicitly point out that this is being modified in the commit
> message. I don't see them being used, so probably not a big deal
> (unless Dave Jiang has something queued that will use it).

Done. I feel like he can always add them back in when he adds the
functionality. This way, when he does, MAX_SPAD will be updated and the
check will still be correct.

> Move this check above the dev_to_node assignment above.

Done.


Logan

[Logan Gunthorpe]

I'm working on hardware that currently has a limited number of
scratchpad registers and ntb_ndev fails with no clue as to why. I
feel it is better to fail early and provide a reasonable error message
then to fail later on.

The same is done to ntb_perf, but it doesn't currently require enough

spads to actually fail. I've also removed the unused SPAD_MSG and
SPAD_ACK enums so that MAX_SPAD accurately reflects the number of
spads used.

Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
---
drivers/ntb/ntb_transport.c | 9 +++++++--
drivers/ntb/test/ntb_perf.c | 8 ++++++--
2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c

index 2ef9d913..6d9940a 100644

--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -1037,6 +1037,13 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
int node;
int rc, i;

+ mw_count = ntb_mw_count(ndev);
+ if (ntb_spad_count(ndev) < (NUM_MWS + 1 + mw_count * 2)) {

+ dev_err(&ndev->dev, "Not enough scratch pad registers for %s",
+ NTB_TRANSPORT_NAME);
+ return -EIO;
+ }
+
if (ntb_db_is_unsafe(ndev))
dev_dbg(&ndev->dev,
"doorbell is unsafe, proceed anyway...\n");
@@ -1052,8 +1059,6 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)

nt->ndev = ndev;

- mw_count = ntb_mw_count(ndev);
-
nt->mw_count = mw_count;

nt->mw_vec = kzalloc_node(mw_count * sizeof(*nt->mw_vec),
diff --git a/drivers/ntb/test/ntb_perf.c b/drivers/ntb/test/ntb_perf.c

index 30635c8..4368519 100644

--- a/drivers/ntb/test/ntb_perf.c
+++ b/drivers/ntb/test/ntb_perf.c
@@ -143,8 +143,6 @@ enum {
VERSION = 0,
MW_SZ_HIGH,
MW_SZ_LOW,
- SPAD_MSG,
- SPAD_ACK,

MAX_SPAD
};

@@ -696,6 +694,12 @@ static int perf_probe(struct ntb_client *client, struct ntb_dev *ntb)
int node;
int rc = 0;

+ if (ntb_spad_count(ntb) < MAX_SPAD) {
+ dev_err(&ntb->dev, "Not enough scratch pad registers for %s",
+ DRIVER_NAME);
+ return -EIO;
+ }

+
node = dev_to_node(&pdev->dev);

perf = kzalloc_node(sizeof(*perf), GFP_KERNEL, node);

--
2.1.4

[Jiang, Dave]

On Tue, 2016-06-07 at 11:20 -0600, Logan Gunthorpe wrote:
> I'm working on hardware that currently has a limited number of
> scratchpad registers and ntb_ndev fails with no clue as to why. I
> feel it is better to fail early and provide a reasonable error
> message
> then to fail later on.
>
> The same is done to ntb_perf, but it doesn't currently require enough
> spads to actually fail. I've also removed the unused SPAD_MSG and
> SPAD_ACK enums so that MAX_SPAD accurately reflects the number of
> spads used.
>
> Signed-off-by: Logan Gunthorpe <log...@deltatee.com>

Acked-by: Dave Jiang <dave....@intel.com>

[Jon Mason]

On Tue, Jun 7, 2016 at 1:24 PM, Jiang, Dave <dave....@intel.com> wrote:
> On Tue, 2016-06-07 at 11:20 -0600, Logan Gunthorpe wrote:
>> I'm working on hardware that currently has a limited number of
>> scratchpad registers and ntb_ndev fails with no clue as to why. I
>> feel it is better to fail early and provide a reasonable error
>> message
>> then to fail later on.
>>
>> The same is done to ntb_perf, but it doesn't currently require enough
>> spads to actually fail. I've also removed the unused SPAD_MSG and
>> SPAD_ACK enums so that MAX_SPAD accurately reflects the number of
>> spads used.
>>
>> Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
>
> Acked-by: Dave Jiang <dave....@intel.com>

Added to the ntb-next branch.

thanks,
Jon

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