From 129134e5415d46f38b9978b3809af94ed649b57d Mon Sep 17 00:00:00 2001 From: Sergey Senozhatsky Date: Fri, 11 Sep 2020 05:07:58 +0200 Subject: media: media/v4l2: remove V4L2_FLAG_MEMORY_NON_CONSISTENT flag The patch partially reverts some of the UAPI bits of the buffer cache management hints. Namely, the queue consistency (memory coherency) user-space hint because, as it turned out, the kernel implementation of this feature was misusing DMA_ATTR_NON_CONSISTENT. The patch reverts both kernel and user space parts: removes the DMA consistency attr functions, rolls back changes to v4l2_requestbuffers, v4l2_create_buffers structures and corresponding UAPI functions (plus compat32 layer) and cleans up the documentation. [hverkuil: fixed a few typos in the commit log] [hverkuil: fixed vb2_core_reqbufs call in drivers/media/dvb-core/dvb_vb2.c] [mchehab: fixed a typo in the commit log: revers->reverts] Signed-off-by: Christoph Hellwig Signed-off-by: Sergey Senozhatsky Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- include/uapi/linux/videodev2.h | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) (limited to 'include/uapi') diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index c7b70ff53bc1..235db7754606 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -191,8 +191,6 @@ enum v4l2_memory { V4L2_MEMORY_DMABUF = 4, }; -#define V4L2_FLAG_MEMORY_NON_CONSISTENT (1 << 0) - /* see also http://vektor.theorem.ca/graphics/ycbcr/ */ enum v4l2_colorspace { /* @@ -949,10 +947,7 @@ struct v4l2_requestbuffers { __u32 type; /* enum v4l2_buf_type */ __u32 memory; /* enum v4l2_memory */ __u32 capabilities; - union { - __u32 flags; - __u32 reserved[1]; - }; + __u32 reserved[1]; }; /* capabilities for struct v4l2_requestbuffers and v4l2_create_buffers */ @@ -2456,9 +2451,6 @@ struct v4l2_dbg_chip_info { * @memory: enum v4l2_memory; buffer memory type * @format: frame format, for which buffers are requested * @capabilities: capabilities of this buffer type. - * @flags: additional buffer management attributes (ignored unless the - * queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability - * and configured for MMAP streaming I/O). * @reserved: future extensions */ struct v4l2_create_buffers { @@ -2467,8 +2459,7 @@ struct v4l2_create_buffers { __u32 memory; struct v4l2_format format; __u32 capabilities; - __u32 flags; - __u32 reserved[6]; + __u32 reserved[7]; }; /* -- cgit v1.2.3 From ad2b9b0f8d0107602bdc1f3b1ab90719842ace11 Mon Sep 17 00:00:00 2001 From: Priyaranjan Jha Date: Thu, 24 Sep 2020 15:23:14 -0700 Subject: tcp: skip DSACKs with dubious sequence ranges Currently, we use length of DSACKed range to compute number of delivered packets. And if sequence range in DSACK is corrupted, we can get bogus dsacked/acked count, and bogus cwnd. This patch put bounds on DSACKed range to skip update of data delivery and spurious retransmission information, if the DSACK is unlikely caused by sender's action: - DSACKed range shouldn't be greater than maximum advertised rwnd. - Total no. of DSACKed segments shouldn't be greater than total no. of retransmitted segs. Unlike spurious retransmits, network duplicates or corrupted DSACKs shouldn't be counted as delivery. Signed-off-by: Priyaranjan Jha Signed-off-by: Neal Cardwell Signed-off-by: Yuchung Cheng Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/uapi/linux/snmp.h | 1 + net/ipv4/proc.c | 1 + net/ipv4/tcp_input.c | 32 +++++++++++++++++++++++++------- 3 files changed, 27 insertions(+), 7 deletions(-) (limited to 'include/uapi') diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index cee9f8e6fce3..f84e7bcad6de 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -288,6 +288,7 @@ enum LINUX_MIB_TCPTIMEOUTREHASH, /* TCPTimeoutRehash */ LINUX_MIB_TCPDUPLICATEDATAREHASH, /* TCPDuplicateDataRehash */ LINUX_MIB_TCPDSACKRECVSEGS, /* TCPDSACKRecvSegs */ + LINUX_MIB_TCPDSACKIGNOREDDUBIOUS, /* TCPDSACKIgnoredDubious */ __LINUX_MIB_MAX }; diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 1074df726ec0..8d5e1695b9aa 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -293,6 +293,7 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TcpTimeoutRehash", LINUX_MIB_TCPTIMEOUTREHASH), SNMP_MIB_ITEM("TcpDuplicateDataRehash", LINUX_MIB_TCPDUPLICATEDATAREHASH), SNMP_MIB_ITEM("TCPDSACKRecvSegs", LINUX_MIB_TCPDSACKRECVSEGS), + SNMP_MIB_ITEM("TCPDSACKIgnoredDubious", LINUX_MIB_TCPDSACKIGNOREDDUBIOUS), SNMP_MIB_SENTINEL }; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 184ea556f50e..b1ce2054291d 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -885,21 +885,34 @@ struct tcp_sacktag_state { struct rate_sample *rate; }; -/* Take a notice that peer is sending D-SACKs */ +/* Take a notice that peer is sending D-SACKs. Skip update of data delivery + * and spurious retransmission information if this DSACK is unlikely caused by + * sender's action: + * - DSACKed sequence range is larger than maximum receiver's window. + * - Total no. of DSACKed segments exceed the total no. of retransmitted segs. + */ static u32 tcp_dsack_seen(struct tcp_sock *tp, u32 start_seq, u32 end_seq, struct tcp_sacktag_state *state) { u32 seq_len, dup_segs = 1; - if (before(start_seq, end_seq)) { - seq_len = end_seq - start_seq; - if (seq_len > tp->mss_cache) - dup_segs = DIV_ROUND_UP(seq_len, tp->mss_cache); - } + if (!before(start_seq, end_seq)) + return 0; + + seq_len = end_seq - start_seq; + /* Dubious DSACK: DSACKed range greater than maximum advertised rwnd */ + if (seq_len > tp->max_window) + return 0; + if (seq_len > tp->mss_cache) + dup_segs = DIV_ROUND_UP(seq_len, tp->mss_cache); + + tp->dsack_dups += dup_segs; + /* Skip the DSACK if dup segs weren't retransmitted by sender */ + if (tp->dsack_dups > tp->total_retrans) + return 0; tp->rx_opt.sack_ok |= TCP_DSACK_SEEN; tp->rack.dsack_seen = 1; - tp->dsack_dups += dup_segs; state->flag |= FLAG_DSACKING_ACK; /* A spurious retransmission is delivered */ @@ -1153,6 +1166,11 @@ static bool tcp_check_dsack(struct sock *sk, const struct sk_buff *ack_skb, } dup_segs = tcp_dsack_seen(tp, start_seq_0, end_seq_0, state); + if (!dup_segs) { /* Skip dubious DSACK */ + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDSACKIGNOREDDUBIOUS); + return false; + } + NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDSACKRECVSEGS, dup_segs); /* D-SACK for already forgotten data... Do dumb counting. */ -- cgit v1.2.3