4.12-stable review patch. If anyone has any objections, please let me know.
------------------ From: Steven Toth <st...@kernellabs.com> commit 6fb05e0dd32e566facb96ea61a48c7488daa5ac3 upstream. Avoid a double fetch by reusing the values from the prior transfer. Originally reported via https://bugzilla.kernel.org/show_bug.cgi?id=195559 Thanks to Pengfei Wang <wpengfein...@gmail.com> for reporting. Signed-off-by: Steven Toth <st...@kernellabs.com> Reported-by: Pengfei Wang <wpengfein...@gmail.com> Signed-off-by: Mauro Carvalho Chehab <mche...@s-opensource.com> Cc: Eduardo Valentin <edu...@amazon.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- drivers/media/pci/saa7164/saa7164-bus.c | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-) --- a/drivers/media/pci/saa7164/saa7164-bus.c +++ b/drivers/media/pci/saa7164/saa7164-bus.c @@ -389,11 +389,11 @@ int saa7164_bus_get(struct saa7164_dev * msg_tmp.size = le16_to_cpu((__force __le16)msg_tmp.size); msg_tmp.command = le32_to_cpu((__force __le32)msg_tmp.command); msg_tmp.controlselector = le16_to_cpu((__force __le16)msg_tmp.controlselector); + memcpy(msg, &msg_tmp, sizeof(*msg)); /* No need to update the read positions, because this was a peek */ /* If the caller specifically want to peek, return */ if (peekonly) { - memcpy(msg, &msg_tmp, sizeof(*msg)); goto peekout; } @@ -438,21 +438,15 @@ int saa7164_bus_get(struct saa7164_dev * space_rem = bus->m_dwSizeGetRing - curr_grp; if (space_rem < sizeof(*msg)) { - /* msg wraps around the ring */ - memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, space_rem); - memcpy_fromio((u8 *)msg + space_rem, bus->m_pdwGetRing, - sizeof(*msg) - space_rem); if (buf) memcpy_fromio(buf, bus->m_pdwGetRing + sizeof(*msg) - space_rem, buf_size); } else if (space_rem == sizeof(*msg)) { - memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg)); if (buf) memcpy_fromio(buf, bus->m_pdwGetRing, buf_size); } else { /* Additional data wraps around the ring */ - memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg)); if (buf) { memcpy_fromio(buf, bus->m_pdwGetRing + curr_grp + sizeof(*msg), space_rem - sizeof(*msg)); @@ -465,15 +459,10 @@ int saa7164_bus_get(struct saa7164_dev * } else { /* No wrapping */ - memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg)); if (buf) memcpy_fromio(buf, bus->m_pdwGetRing + curr_grp + sizeof(*msg), buf_size); } - /* Convert from little endian to CPU */ - msg->size = le16_to_cpu((__force __le16)msg->size); - msg->command = le32_to_cpu((__force __le32)msg->command); - msg->controlselector = le16_to_cpu((__force __le16)msg->controlselector); /* Update the read positions, adjusting the ring */ saa7164_writel(bus->m_dwGetReadPos, new_grp);
