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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Chuanhua Han <chuanhua.han@nxp.com>,
        Boris Brezillon <boris.brezillon@bootlin.com>,
        Mark Brown <broonie@kernel.org>
Subject: [PATCH 4.19 009/361] spi: spi-mem: Adjust op len based on message/transfer size limitations
Date:   Sun, 11 Nov 2018 14:15:56 -0800
Message-Id: <20181111221621.232433284@linuxfoundation.org>
In-Reply-To: <20181111221619.915519183@linuxfoundation.org>
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4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chuanhua Han <chuanhua.han@nxp.com>

commit e757996cafbeb6b71234a17130674bcd8f44c59e upstream.

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.

Fixes: c36ff266dc82 ("spi: Extend the core to ease integration of SPI memory controllers")
Cc: <stable@vger.kernel.org>
Signed-off-by: Chuanhua Han <chuanhua.han@nxp.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- 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);