From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm0-x241.google.com ([2a00:1450:400c:c09::241]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1c00CE-0000Wx-Pa for linux-mtd@lists.infradead.org; Fri, 28 Oct 2016 05:59:20 +0000 Received: by mail-wm0-x241.google.com with SMTP id b80so5782464wme.2 for ; Thu, 27 Oct 2016 22:58:58 -0700 (PDT) Subject: [PATCH v2] mtd: m25p80: consider max message size in m25p80_read To: Cyrille Pitchen References: <6c95366c-7fcc-ef4c-033a-f9f6e152a669@gmail.com> <20160816164204.GV9347@sirena.org.uk> Cc: Brian Norris , Mark Brown , "linux-spi@vger.kernel.org" , MTD Maling List From: Heiner Kallweit Message-ID: <0e38d1ed-af5c-160f-e02a-f1433c507d23@gmail.com> Date: Fri, 28 Oct 2016 07:58:46 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Consider a message size limit when calculating the maximum amount of data that can be read. The message size limit has been introduced with 4.9, so cc it to stable. Signed-off-by: Heiner Kallweit Cc: # 4.9.x --- v2: - This patch was part of a series and the other patches of the series went into 4.9. It's needed to correctly support reads > 64k on fsl-espi as first user of spi_max_message_size. See commit 02a595d5d6e4 ("spi: fsl-espi: eliminate spi nor flash read loop"). CC it to stable. --- drivers/mtd/devices/m25p80.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c index 9cf7fcd..16a7df2 100644 --- a/drivers/mtd/devices/m25p80.c +++ b/drivers/mtd/devices/m25p80.c @@ -172,7 +172,8 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len, t[1].rx_buf = buf; t[1].rx_nbits = m25p80_rx_nbits(nor); - t[1].len = min(len, spi_max_transfer_size(spi)); + t[1].len = min3(len, spi_max_transfer_size(spi), + spi_max_message_size(spi) - t[0].len); spi_message_add_tail(&t[1], &m); ret = spi_sync(spi, &m); -- 2.9.2