From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read The buffered read collector zero-fills the tail of a short read that stops below the inode's i_size (netfs_clear_unread()), so a read that races an extending write still returns the expected number of bytes. The non-buffered collector path does no such thing: it just records how much was transferred. Add the same zero-fill for the non-buffered case, gated on NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short result from it is known to be safe to treat as a hole, as opposed to NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of the file and should be reported short as-is. Only CLEAR_TAIL should zero-fill here; a real EOF must stay a real short read. No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest, so this is inert on its own -- a following change teaches cifs to set it in the one case that needs it. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Reviewed-by: David Howells Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- drivers/net/netdevsim/tc.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 drivers/net/netdevsim/tc.c (limited to 'drivers/net/netdevsim/tc.c') diff --git a/drivers/net/netdevsim/tc.c b/drivers/net/netdevsim/tc.c new file mode 100644 index 000000000..a415e02a6 --- /dev/null +++ b/drivers/net/netdevsim/tc.c @@ -0,0 +1,97 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include + +#include "netdevsim.h" + +static int +nsim_setup_tc_block_cb(enum tc_setup_type type, void *type_data, void *cb_priv) +{ + struct flow_cls_common_offload *common = type_data; + int err = 0; + + switch (type) { + case TC_SETUP_CLSBPF: + err = nsim_bpf_setup_tc_block_cb(type, type_data, cb_priv); + break; + case TC_SETUP_CLSFLOWER: + break; + default: + NSIM_EA(common->extack, "offload type not supported"); + err = -EOPNOTSUPP; + break; + } + + return err; +} + +static void nsim_taprio_stats(struct tc_taprio_qopt_stats *stats) +{ + stats->window_drops = 0; + stats->tx_overruns = 0; +} + +static int nsim_setup_tc_taprio(struct net_device *dev, + struct tc_taprio_qopt_offload *offload) +{ + int err = 0; + + switch (offload->cmd) { + case TAPRIO_CMD_REPLACE: + case TAPRIO_CMD_DESTROY: + break; + case TAPRIO_CMD_STATS: + nsim_taprio_stats(&offload->stats); + break; + default: + err = -EOPNOTSUPP; + } + + return err; +} + +static int nsim_setup_tc_ets(struct net_device *dev, + struct tc_ets_qopt_offload *offload) +{ + int err = 0; + + switch (offload->command) { + case TC_ETS_REPLACE: + case TC_ETS_DESTROY: + break; + case TC_ETS_STATS: + _bstats_update(offload->stats.bstats, 0, 0); + break; + default: + err = -EOPNOTSUPP; + } + + return err; +} + +static LIST_HEAD(nsim_block_cb_list); + +int +nsim_setup_tc(struct net_device *dev, enum tc_setup_type type, void *type_data) +{ + struct netdevsim *ns = netdev_priv(dev); + + switch (type) { + case TC_SETUP_QDISC_TAPRIO: + return nsim_setup_tc_taprio(dev, type_data); + case TC_SETUP_QDISC_ETS: + return nsim_setup_tc_ets(dev, type_data); + case TC_SETUP_BLOCK: + return flow_block_cb_setup_simple(type_data, + &nsim_block_cb_list, + nsim_setup_tc_block_cb, + ns, ns, true); + case TC_SETUP_FT: + return 0; + default: + return -EOPNOTSUPP; + } +} +ALLOW_ERROR_INJECTION(nsim_setup_tc, ERRNO); -- cgit v1.3.1