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

[Logan Gunthorpe]

Ok, I'll add a comment.

Logan

On 10/06/16 08:35 PM, Allen Hubbe wrote:
> On Fri, Jun 10, 2016 at 6:54 PM, Logan Gunthorpe <logang@xxxxxxxxxxxx> 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 <logang@xxxxxxxxxxxx>
>
> 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.Hubbe@xxxxxxx>
>
> > ---
> >   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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