-----Original Message-----
From: Boris Brezillon <redacted>
Sent: 2018年8月30日 16:47
To: Chuanhua Han <redacted>
Cc: broonie@kernel.org; linux-spi@vger.kernel.org;
linux-kernel@vger.kernel.org; stable@vger.kernel.org
Subject: Re: [PATCH v5] spi: spi-mem: Adjust op len based on message/transfer
size limitations

Hi Chuanhua,

On Thu, 30 Aug 2018 16:43:24 +0800
Chuanhua Han [off-list ref] wrote:

quoted

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.

You already sent this email a few days back. Please wait a bit before sending it
again. And when you do so and nothing changed in the patch please use the
[PATCH RESEND vX] prefix and explain why you resend it.

I have modified the patch for the comment you mentioned last time. Do you need any other modification？

Thanks,

Boris

quoted

Fixes: c36ff266dc82 ("spi: Extend the core to ease integration of SPI
memory controllers")
Cc: <redacted>
Signed-off-by: Chuanhua Han <redacted>
Reviewed-by: Boris Brezillon <redacted>
---
Changes in v5:
  -Add the validation check after the op->data.nbytes assignment
  -Assign the "len" variable after defining it
  -Remove the brackets on both sides of "opt-> data.nbytes"
Changes in v4:
  -Rename variable name "opcode_addr_dummy_sum" to "len"
  -The comparison of "spi_max_message_size(mem->spi)" and "len" was

removed

quoted

  -Adjust their order when comparing the sizes of

"spi_max_message_size(mem->spi)" and "len"

quoted

  -Changing the "unsigned long" type in the code to "size_t"
Changes in v3:
  -Rename variable name "val" to "opcode_addr_dummy_sum"
  -Place the legitimacy of the transfer size(i.e.,
"spi_max_message_size(mem->spi)" and
"opcode_addr_dummy_sum") into "if (! ctlr - > mem_ops | |! ctlr->

mem_ops->exec_op) {"

quoted

structure and add "spi_max_transfer_size(mem->spi) and

opcode_addr_dummy_sum"

quoted

  -Adjust the formatting alignment of the code
  -"(unsigned long)op->data.nbytes" was modified to "(unsigned

long)(op->data.nbytes)"

quoted

Changes in v2:
  -Place the adjusted transfer bytes code in spi_mem_adjust_op_size()
and  check
spi_max_message_size(mem->spi) value before subtracting opcode, addr and

dummy bytes

quoted

  -Change the code from fsl-espi controller to generic code(The
adjustment of spi transmission length was originally modified in the
"drivers/spi/spi-fsl-espi.c" file, and now the adjustment of transfer
length is made in the "drivers/spi/spi-mem.c" file)

 drivers/spi/spi-mem.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c index

e43842c..eb72dba 100644

--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c

@@ -346,10 +346,25 @@ EXPORT_SYMBOL_GPL(spi_mem_get_name);
 int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op

*op)  {
 	struct spi_controller *ctlr = mem->spi->controller;
+	size_t 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 (len > spi_max_transfer_size(mem->spi))
+			return -EINVAL;
+
+		op->data.nbytes = min3((size_t)op->data.nbytes,
+				       spi_max_transfer_size(mem->spi),
+				       spi_max_message_size(mem->spi) -
+				       len);
+		if (!op->data.nbytes)
+			return -EINVAL;
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);