When all we do with an Error we receive into a local variable is propagating to somewhere else, we can just as well receive it there right away. Convert if (!foo(..., &err)) { ... error_propagate(errp, err); ... return ... } to if (!foo(..., errp)) { ... ... return ... } where nothing else needs @err. Coccinelle script: @rule1 forall@ identifier fun, err, errp, lbl; expression list args, args2; binary operator op; constant c1, c2; symbol false; @@ if ( ( - fun(args, &err, args2) + fun(args, errp, args2) | - !fun(args, &err, args2) + !fun(args, errp, args2) | - fun(args, &err, args2) op c1 + fun(args, errp, args2) op c1 ) ) { ... when != err when != lbl: when strict - error_propagate(errp, err); ... when != err ( return; | return c2; | return false; ) } @rule2 forall@ identifier fun, err, errp, lbl; expression list args, args2; expression var; binary operator op; constant c1, c2; symbol false; @@ - var = fun(args, &err, args2); + var = fun(args, errp, args2); ... when != err if ( ( var | !var | var op c1 ) ) { ... when != err when != lbl: when strict - error_propagate(errp, err); ... when != err ( return; | return c2; | return false; | return var; ) } @depends on rule1 || rule2@ identifier err; @@ - Error *err = NULL; ... when != err Not exactly elegant, I'm afraid. The "when != lbl:" is necessary to avoid transforming if (fun(args, &err)) { goto out } ... out: error_propagate(errp, err); even though other paths to label out still need the error_propagate(). For an actual example, see sclp_realize(). Without the "when strict", Coccinelle transforms vfio_msix_setup(), incorrectly. I don't know what exactly "when strict" does, only that it helps here. The match of return is narrower than what I want, but I can't figure out how to express "return where the operand doesn't use @err". For an example where it's too narrow, see vfio_intx_enable(). Silently fails to convert hw/arm/armsse.c, because Coccinelle gets confused by ARMSSE being used both as typedef and function-like macro there. Converted manually. Line breaks tidied up manually. One nested declaration of @local_err deleted manually. Preexisting unwanted blank line dropped in hw/riscv/sifive_e.c. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200707160613.848843-35-armbru@redhat.com>
207 lines
6.1 KiB
C
207 lines
6.1 KiB
C
/*
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* Copyright (c) 2015 FUJITSU LIMITED
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* Author: Yang Hongyang <yanghy@cn.fujitsu.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or
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* later. See the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "net/filter.h"
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#include "net/queue.h"
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#include "qapi/error.h"
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#include "qemu/timer.h"
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#include "qemu/iov.h"
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#include "qapi/qapi-builtin-visit.h"
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#include "qapi/qmp/qerror.h"
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#include "qom/object.h"
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#define TYPE_FILTER_BUFFER "filter-buffer"
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#define FILTER_BUFFER(obj) \
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OBJECT_CHECK(FilterBufferState, (obj), TYPE_FILTER_BUFFER)
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typedef struct FilterBufferState {
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NetFilterState parent_obj;
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NetQueue *incoming_queue;
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uint32_t interval;
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QEMUTimer release_timer;
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} FilterBufferState;
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static void filter_buffer_flush(NetFilterState *nf)
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{
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FilterBufferState *s = FILTER_BUFFER(nf);
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if (!qemu_net_queue_flush(s->incoming_queue)) {
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/* Unable to empty the queue, purge remaining packets */
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qemu_net_queue_purge(s->incoming_queue, nf->netdev);
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}
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}
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static void filter_buffer_release_timer(void *opaque)
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{
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NetFilterState *nf = opaque;
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FilterBufferState *s = FILTER_BUFFER(nf);
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/*
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* Note: filter_buffer_flush() drops packets that can't be sent
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* TODO: We should leave them queued. But currently there's no way
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* for the next filter or receiver to notify us that it can receive
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* more packets.
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*/
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filter_buffer_flush(nf);
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/* Timer rearmed to fire again in s->interval microseconds. */
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timer_mod(&s->release_timer,
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qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
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}
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/* filter APIs */
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static ssize_t filter_buffer_receive_iov(NetFilterState *nf,
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NetClientState *sender,
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unsigned flags,
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const struct iovec *iov,
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int iovcnt,
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NetPacketSent *sent_cb)
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{
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FilterBufferState *s = FILTER_BUFFER(nf);
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/*
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* We return size when buffer a packet, the sender will take it as
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* a already sent packet, so sent_cb should not be called later.
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*
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* FIXME: Even if the guest can't receive packets for some reasons,
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* the filter can still accept packets until its internal queue is full.
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* For example:
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* For some reason, receiver could not receive more packets
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* (.can_receive() returns false). Without a filter, at most one packet
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* will be queued in incoming queue and sender's poll will be disabled
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* unit its sent_cb() was called. With a filter, it will keep receiving
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* the packets without caring about the receiver. This is suboptimal.
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* May need more thoughts (e.g keeping sent_cb).
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*/
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qemu_net_queue_append_iov(s->incoming_queue, sender, flags,
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iov, iovcnt, NULL);
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return iov_size(iov, iovcnt);
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}
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static void filter_buffer_cleanup(NetFilterState *nf)
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{
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FilterBufferState *s = FILTER_BUFFER(nf);
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if (s->interval) {
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timer_del(&s->release_timer);
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}
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/* flush packets */
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if (s->incoming_queue) {
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filter_buffer_flush(nf);
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g_free(s->incoming_queue);
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}
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}
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static void filter_buffer_setup_timer(NetFilterState *nf)
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{
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FilterBufferState *s = FILTER_BUFFER(nf);
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if (s->interval) {
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timer_init_us(&s->release_timer, QEMU_CLOCK_VIRTUAL,
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filter_buffer_release_timer, nf);
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/* Timer armed to fire in s->interval microseconds. */
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timer_mod(&s->release_timer,
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qemu_clock_get_us(QEMU_CLOCK_VIRTUAL) + s->interval);
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}
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}
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static void filter_buffer_setup(NetFilterState *nf, Error **errp)
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{
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FilterBufferState *s = FILTER_BUFFER(nf);
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/*
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* We may want to accept zero interval when VM FT solutions like MC
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* or COLO use this filter to release packets on demand.
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*/
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if (!s->interval) {
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error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "interval",
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"a non-zero interval");
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return;
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}
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s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
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filter_buffer_setup_timer(nf);
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}
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static void filter_buffer_status_changed(NetFilterState *nf, Error **errp)
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{
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FilterBufferState *s = FILTER_BUFFER(nf);
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if (!nf->on) {
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if (s->interval) {
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timer_del(&s->release_timer);
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}
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filter_buffer_flush(nf);
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} else {
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filter_buffer_setup_timer(nf);
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}
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}
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static void filter_buffer_class_init(ObjectClass *oc, void *data)
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{
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NetFilterClass *nfc = NETFILTER_CLASS(oc);
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nfc->setup = filter_buffer_setup;
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nfc->cleanup = filter_buffer_cleanup;
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nfc->receive_iov = filter_buffer_receive_iov;
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nfc->status_changed = filter_buffer_status_changed;
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}
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static void filter_buffer_get_interval(Object *obj, Visitor *v,
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const char *name, void *opaque,
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Error **errp)
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{
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FilterBufferState *s = FILTER_BUFFER(obj);
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uint32_t value = s->interval;
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visit_type_uint32(v, name, &value, errp);
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}
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static void filter_buffer_set_interval(Object *obj, Visitor *v,
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const char *name, void *opaque,
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Error **errp)
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{
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FilterBufferState *s = FILTER_BUFFER(obj);
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uint32_t value;
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if (!visit_type_uint32(v, name, &value, errp)) {
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return;
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}
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if (!value) {
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error_setg(errp, "Property '%s.%s' requires a positive value",
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object_get_typename(obj), name);
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return;
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}
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s->interval = value;
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}
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static void filter_buffer_init(Object *obj)
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{
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object_property_add(obj, "interval", "uint32",
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filter_buffer_get_interval,
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filter_buffer_set_interval, NULL, NULL);
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}
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static const TypeInfo filter_buffer_info = {
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.name = TYPE_FILTER_BUFFER,
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.parent = TYPE_NETFILTER,
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.class_init = filter_buffer_class_init,
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.instance_init = filter_buffer_init,
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.instance_size = sizeof(FilterBufferState),
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};
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static void register_types(void)
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{
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type_register_static(&filter_buffer_info);
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}
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type_init(register_types);
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