6.10-stable review patch. If anyone has any objections, please let me know.
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From: Douglas Anderson dianders@chromium.org
[ Upstream commit 0b03829fdece47beba9ecb7dbcbde4585ee3663e ]
The mipi_dsi_dcs_write_seq() macro makes a call to mipi_dsi_dcs_write_buffer() which returns a type ssize_t. The macro then stores it in an int and checks to see if it's negative. This could theoretically be a problem if "ssize_t" is larger than "int".
To see the issue, imagine that "ssize_t" is 32-bits and "int" is 16-bits, you could see a problem if there was some code out there that looked like:
mipi_dsi_dcs_write_seq(dsi, cmd, <32767 bytes as arguments>);
...since we'd get back that 32768 bytes were transferred and 32768 stored in a 16-bit int would look negative.
Though there are no callsites where we'd actually hit this (even if "int" was only 16-bit), it's cleaner to make the types match so let's fix it.
Fixes: 2a9e9daf7523 ("drm/mipi-dsi: Introduce mipi_dsi_dcs_write_seq macro") Reviewed-by: Neil Armstrong neil.armstrong@linaro.org Reviewed-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Douglas Anderson dianders@chromium.org Link: https://lore.kernel.org/r/20240514102056.v5.1.I30fa4c8348ea316c886ef8a522a52... Signed-off-by: Neil Armstrong neil.armstrong@linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20240514102056.v5.1.I30fa4c834... Signed-off-by: Sasha Levin sashal@kernel.org --- include/drm/drm_mipi_dsi.h | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h index 82b1cc434ea3f..70ce0b8cbc68e 100644 --- a/include/drm/drm_mipi_dsi.h +++ b/include/drm/drm_mipi_dsi.h @@ -333,18 +333,18 @@ int mipi_dsi_dcs_get_display_brightness_large(struct mipi_dsi_device *dsi, * @cmd: Command * @seq: buffer containing data to be transmitted */ -#define mipi_dsi_dcs_write_seq(dsi, cmd, seq...) \ - do { \ - static const u8 d[] = { cmd, seq }; \ - struct device *dev = &dsi->dev; \ - int ret; \ - ret = mipi_dsi_dcs_write_buffer(dsi, d, ARRAY_SIZE(d)); \ - if (ret < 0) { \ - dev_err_ratelimited( \ - dev, "sending command %#02x failed: %d\n", \ - cmd, ret); \ - return ret; \ - } \ +#define mipi_dsi_dcs_write_seq(dsi, cmd, seq...) \ + do { \ + static const u8 d[] = { cmd, seq }; \ + struct device *dev = &dsi->dev; \ + ssize_t ret; \ + ret = mipi_dsi_dcs_write_buffer(dsi, d, ARRAY_SIZE(d)); \ + if (ret < 0) { \ + dev_err_ratelimited( \ + dev, "sending command %#02x failed: %zd\n", \ + cmd, ret); \ + return ret; \ + } \ } while (0)
/**