[PATCH 5/8] ntb_tool: BUG: Ensure the buffer size is large enough to return all spads

[Logan Gunthorpe]

On hardware with 32 scratchpad registers the spad field in ntb tool
could chop off the end. The maximum buffer size is increased from
256 to 15 times the number or scratchpads.

Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
---
drivers/ntb/test/ntb_tool.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/ntb/test/ntb_tool.c b/drivers/ntb/test/ntb_tool.c
index 4c01057..954e1d5 100644
--- a/drivers/ntb/test/ntb_tool.c
+++ b/drivers/ntb/test/ntb_tool.c
@@ -368,7 +368,9 @@ static ssize_t tool_spadfn_read(struct tool_ctx *tc, char __user *ubuf,
if (!spad_read_fn)
return -EINVAL;

- buf_size = min_t(size_t, size, 0x100);
+ spad_count = ntb_spad_count(tc->ntb);
+
+ buf_size = min_t(size_t, size, spad_count * 15);

buf = kmalloc(buf_size, GFP_KERNEL);
if (!buf)
@@ -376,7 +378,6 @@ static ssize_t tool_spadfn_read(struct tool_ctx *tc, char __user *ubuf,

pos = 0;

- spad_count = ntb_spad_count(tc->ntb);
for (i = 0; i < spad_count; ++i) {
pos += scnprintf(buf + pos, buf_size - pos, "%d\t%#x\n",
i, spad_read_fn(tc->ntb, i));
--
2.1.4

[Allen Hubbe]

On Fri, Jun 10, 2016 at 6:54 PM, Logan Gunthorpe <log...@deltatee.com> wrote:
> On hardware with 32 scratchpad registers the spad field in ntb tool
> could chop off the end. The maximum buffer size is increased from
> 256 to 15 times the number or scratchpads.
>
> Signed-off-by: Logan Gunthorpe <log...@deltatee.com>

It could be marginally better if there was an explanation to accompany
the magic number 15, but it's not a big deal. One might guess it has
something to do with the expected length of the formatted string.

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

> ---
> drivers/ntb/test/ntb_tool.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/ntb/test/ntb_tool.c b/drivers/ntb/test/ntb_tool.c
> index 4c01057..954e1d5 100644
> --- a/drivers/ntb/test/ntb_tool.c
> +++ b/drivers/ntb/test/ntb_tool.c
> @@ -368,7 +368,9 @@ static ssize_t tool_spadfn_read(struct tool_ctx *tc, char __user *ubuf,
> if (!spad_read_fn)
> return -EINVAL;
>
> - buf_size = min_t(size_t, size, 0x100);
> + spad_count = ntb_spad_count(tc->ntb);
> +
> + buf_size = min_t(size_t, size, spad_count * 15);
>
> buf = kmalloc(buf_size, GFP_KERNEL);
> if (!buf)
> @@ -376,7 +378,6 @@ static ssize_t tool_spadfn_read(struct tool_ctx *tc, char __user *ubuf,
>
> pos = 0;
>
> - spad_count = ntb_spad_count(tc->ntb);
> for (i = 0; i < spad_count; ++i) {
> pos += scnprintf(buf + pos, buf_size - pos, "%d\t%#x\n",
> i, spad_read_fn(tc->ntb, i));
> --
> 2.1.4
>

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[Logan Gunthorpe]

Ok, I'll add a comment.

Logan