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e2e1c7bda4
Dealing with the return value of get_user_pages*() variants has a few classic pitfalls, and this driver found one of them: the return value might be zero, positive, or -errno. And if positive, it might be fewer pages than were requested. And if fewer pages than requested, then the caller should return (via put_page()) the pages that *were* pinned. This driver was doing that *except* that it had a problem with the -errno case, which was being stored in an unsigned int, and which would case an interesting mess if it ever happened: nr_pages would be interpreted as a spectacularly huge unsigned value, rather than a small negative value. Also, it was unnecessarily overriding a potentially informative -errno, with -EINVAL, in some cases. Instead: clamp the nr_pages to zero or positive, so that the error handling works. And return the -errno value from get_user_pages*(), unchanged, if we get one. And explain this with comments, seeing as how it is error-prone. Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Gustavo A. R. Silva <gustavo@embeddedor.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: dri-devel@lists.freedesktop.org Cc: linux-fbdev@vger.kernel.org Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200522041506.39638-2-jhubbard@nvidia.com |
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| backlight | ||
| console | ||
| fbdev | ||
| logo | ||
| display_timing.c | ||
| hdmi.c | ||
| Kconfig | ||
| Makefile | ||
| of_display_timing.c | ||
| of_videomode.c | ||
| vgastate.c | ||
| videomode.c | ||