2018-08-20 12:58:43

by Chuanhua Han

[permalink] [raw]
Subject: [PATCH] mtd: m25p80: consider max message size when use the spi_mem_xx() API

Signed-off-by: Chuanhua Han <[email protected]>
---
Changes in v3:
Rename variable name "val" to "opcode_addr_dummy_sum".
Place the legitimacy of the transfer size(i.e., "pi_max_message_size(mem->spi)" and
"opcode_addr_dummy_sum") into "if (! ctlr - > mem_ops | |! ctlr-> mem_ops->exec_op) {"
structure and add "spi_max_transfer_size(mem->spi) and opcode_addr_dummy_sum".
Adjust the formatting alignment of your code.
"(unsigned long)op->data.nbytes" was modified to "(unsigned long)(op->data.nbytes)".

Fixes: c36ff266dc82 ("spi: Extend the core to ease integration of SPI memory controllers")
---
drivers/spi/spi-mem.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index 990770d..5ec2bc9 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -328,10 +328,24 @@ EXPORT_SYMBOL_GPL(spi_mem_exec_op);
int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
{
struct spi_controller *ctlr = mem->spi->controller;
+ unsigned long opcode_addr_dummy_sum = sizeof(op->cmd.opcode) +
+ op->addr.nbytes +
+ op->dummy.nbytes;

if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
return ctlr->mem_ops->adjust_op_size(mem, op);

+ if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
+ if (spi_max_message_size(mem->spi) < opcode_addr_dummy_sum ||
+ spi_max_transfer_size(mem->spi) < opcode_addr_dummy_sum)
+ return -EINVAL;
+
+ op->data.nbytes = min3((unsigned long)(op->data.nbytes),
+ spi_max_transfer_size(mem->spi),
+ spi_max_message_size(mem->spi) -
+ opcode_addr_dummy_sum);
+ }
+
return 0;
}
EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);
--
2.7.4



2018-08-20 13:26:05

by David Laight

[permalink] [raw]
Subject: RE: [PATCH] mtd: m25p80: consider max message size when use the spi_mem_xx() API

From: Chuanhua Han
> Sent: 20 August 2018 13:44
>
> Signed-off-by: Chuanhua Han <[email protected]>
> ---
> Changes in v3:
> Rename variable name "val" to "opcode_addr_dummy_sum".
> Place the legitimacy of the transfer size(i.e., "pi_max_message_size(mem->spi)" and
> "opcode_addr_dummy_sum") into "if (! ctlr - > mem_ops | |! ctlr-> mem_ops->exec_op) {"
> structure and add "spi_max_transfer_size(mem->spi) and opcode_addr_dummy_sum".
> Adjust the formatting alignment of your code.
> "(unsigned long)op->data.nbytes" was modified to "(unsigned long)(op->data.nbytes)".
>
> Fixes: c36ff266dc82 ("spi: Extend the core to ease integration of SPI memory controllers")
> ---
> drivers/spi/spi-mem.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
> index 990770d..5ec2bc9 100644
> --- a/drivers/spi/spi-mem.c
> +++ b/drivers/spi/spi-mem.c
> @@ -328,10 +328,24 @@ EXPORT_SYMBOL_GPL(spi_mem_exec_op);
> int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
> {
> struct spi_controller *ctlr = mem->spi->controller;
> + unsigned long opcode_addr_dummy_sum = sizeof(op->cmd.opcode) +
> + op->addr.nbytes +
> + op->dummy.nbytes;

I'd split that (and shorten the variable name) to avoid line wrap. Maybe:

unsigned long len;

len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
>
> if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
> return ctlr->mem_ops->adjust_op_size(mem, op);
>
> + if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
> + if (spi_max_message_size(mem->spi) < opcode_addr_dummy_sum ||
> + spi_max_transfer_size(mem->spi) < opcode_addr_dummy_sum)
> + return -EINVAL;

Those comparisons are lexically backwards, you want 'value op constant'.
So:
if (len > spi_max_message_size(mem->spi) ||
len > spi_max_transfer_size(mem->spi))
return -EINVAL.
Although I'm surprised you need to do both comparisons.

> +
> + op->data.nbytes = min3((unsigned long)(op->data.nbytes),
> + spi_max_transfer_size(mem->spi),
> + spi_max_message_size(mem->spi) -
> + opcode_addr_dummy_sum);

That looks like a strange limit...

> + }
> +
> return 0;
> }
> EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);
> --
> 2.7.4

David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


2018-08-20 13:57:15

by Boris Brezillon

[permalink] [raw]
Subject: Re: [PATCH] mtd: m25p80: consider max message size when use the spi_mem_xx() API

On Mon, 20 Aug 2018 13:01:13 +0000
David Laight <[email protected]> wrote:

> From: Chuanhua Han
> > Sent: 20 August 2018 13:44
> >

Still no message here, and the subject prefix is still wrong.


Fixes and Cc-stable tags should be placed here...

> > Signed-off-by: Chuanhua Han <[email protected]>
> > ---
> > Changes in v3:
> > Rename variable name "val" to "opcode_addr_dummy_sum".
> > Place the legitimacy of the transfer size(i.e., "pi_max_message_size(mem->spi)" and
> > "opcode_addr_dummy_sum") into "if (! ctlr - > mem_ops | |! ctlr-> mem_ops->exec_op) {"
> > structure and add "spi_max_transfer_size(mem->spi) and opcode_addr_dummy_sum".
> > Adjust the formatting alignment of your code.
> > "(unsigned long)op->data.nbytes" was modified to "(unsigned long)(op->data.nbytes)".
> >
> > Fixes: c36ff266dc82 ("spi: Extend the core to ease integration of SPI memory controllers")

... not here.

The changelog should also contain a "Changes in v2" section.

> > ---
> > drivers/spi/spi-mem.c | 14 ++++++++++++++
> > 1 file changed, 14 insertions(+)
> >
> > diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
> > index 990770d..5ec2bc9 100644
> > --- a/drivers/spi/spi-mem.c
> > +++ b/drivers/spi/spi-mem.c
> > @@ -328,10 +328,24 @@ EXPORT_SYMBOL_GPL(spi_mem_exec_op);
> > int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
> > {
> > struct spi_controller *ctlr = mem->spi->controller;
> > + unsigned long opcode_addr_dummy_sum = sizeof(op->cmd.opcode) +
> > + op->addr.nbytes +
> > + op->dummy.nbytes;
>

Yep, the var name is definitely too long.

> I'd split that (and shorten the variable name) to avoid line wrap. Maybe:
>
> unsigned long len;
>
> len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
> >
> > if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
> > return ctlr->mem_ops->adjust_op_size(mem, op);
> >
> > + if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
> > + if (spi_max_message_size(mem->spi) < opcode_addr_dummy_sum ||
> > + spi_max_transfer_size(mem->spi) < opcode_addr_dummy_sum)
> > + return -EINVAL;
>
> Those comparisons are lexically backwards, you want 'value op constant'.
> So:
> if (len > spi_max_message_size(mem->spi) ||
> len > spi_max_transfer_size(mem->spi))
> return -EINVAL.
> Although I'm surprised you need to do both comparisons.

Indeed, spi_max_transfer_size() is enough since it already does a min()
with spi_max_message_size().

>
> > +
> > + op->data.nbytes = min3((unsigned long)(op->data.nbytes),

Hm, you should have a cast of size_t, I guess that's what kbuild robots
reported.

> > + spi_max_transfer_size(mem->spi),
> > + spi_max_message_size(mem->spi) -
> > + opcode_addr_dummy_sum);
>
> That looks like a strange limit...

We need that to adjust the len of the 2nd transfer (called data in
spi-mem) if it's too long to fit in a SPI message or SPI transfer.

>
> > + }
> > +
> > return 0;
> > }
> > EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);
> > --
> > 2.7.4
>
> David
>
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> Registration No: 1397386 (Wales)
>