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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Mikulas Patocka" <mpatocka@redhat.com>,
        "Bartlomiej Zolnierkiewicz" <b.zolnierkie@samsung.com>
Date:   Sun, 09 Dec 2018 21:50:33 +0000
Message-ID: <lsq.1544392233.277462318@decadent.org.uk>
Subject: [PATCH 3.16 061/328] udlfb: make a local copy of fb_ops
In-Reply-To: <lsq.1544392232.713909046@decadent.org.uk>
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3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Mikulas Patocka <mpatocka@redhat.com>

commit 2c29cfc3eaf11779176bf41475cfca49bccba11c upstream.

The defio subsystem overwrites the method fb_osp->mmap. That method is
stored in module's static data - and that means that if we have multiple
diplaylink adapters, they will over write each other's method.

In order to avoid interference between multiple adapters, we copy the
fb_ops structure to a device-local memory.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
[bwh: Backported to 3.16: Pointer to struct dlfb_data is named "dev" rather
 than "dlfb"]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/video/fbdev/udlfb.c | 3 ++-
 include/video/udlfb.h       | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/video/fbdev/udlfb.c
+++ b/drivers/video/fbdev/udlfb.c
@@ -1680,7 +1680,8 @@ static void dlfb_init_framebuffer_work(s
 	dev->info = info;
 	info->par = dev;
 	info->pseudo_palette = dev->pseudo_palette;
-	info->fbops = &dlfb_ops;
+	dev->ops = dlfb_ops;
+	info->fbops = &dev->ops;
 
 	retval = fb_alloc_cmap(&info->cmap, 256, 0);
 	if (retval < 0) {
--- a/include/video/udlfb.h
+++ b/include/video/udlfb.h
@@ -51,6 +51,7 @@ struct dlfb_data {
 	int base8;
 	u32 pseudo_palette[256];
 	int blank_mode; /*one of FB_BLANK_ */
+	struct fb_ops ops;
 	/* blit-only rendering path metrics, exposed through sysfs */
 	atomic_t bytes_rendered; /* raw pixel-bytes driver asked to render */
 	atomic_t bytes_identical; /* saved effort with backbuffer comparison */