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From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Ian Jackson <iwj@xenproject.org>, Julien Grall <julien@xen.org>,
	Wei Liu <wl@xen.org>, Stefano Stabellini <sstabellini@kernel.org>
Subject: [PATCH v5 5/6] evtchn: type adjustments
Date: Wed, 27 Jan 2021 09:17:22 +0100	[thread overview]
Message-ID: <3cb6de31-39e3-43ff-2a9f-a09aa1b1fc26@suse.com> (raw)
In-Reply-To: <306e62e8-9070-2db9-c959-858465c50c1d@suse.com>

First of all avoid "long" when "int" suffices, i.e. in particular when
merely conveying error codes. 32-bit values are slightly cheaper to
deal with on x86, and their processing is at least no more expensive on
Arm. Where possible use evtchn_port_t for port numbers and unsigned int
for other unsigned quantities in adjacent code. In evtchn_set_priority()
eliminate a local variable altogether instead of changing its type.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v4: New.

--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -287,13 +287,12 @@ void evtchn_free(struct domain *d, struc
     xsm_evtchn_close_post(chn);
 }
 
-static long evtchn_alloc_unbound(evtchn_alloc_unbound_t *alloc)
+static int evtchn_alloc_unbound(evtchn_alloc_unbound_t *alloc)
 {
     struct evtchn *chn;
     struct domain *d;
-    int            port;
+    int            port, rc;
     domid_t        dom = alloc->dom;
-    long           rc;
 
     d = rcu_lock_domain_by_any_id(dom);
     if ( d == NULL )
@@ -346,13 +345,13 @@ static void double_evtchn_unlock(struct
     evtchn_write_unlock(rchn);
 }
 
-static long evtchn_bind_interdomain(evtchn_bind_interdomain_t *bind)
+static int evtchn_bind_interdomain(evtchn_bind_interdomain_t *bind)
 {
     struct evtchn *lchn, *rchn;
     struct domain *ld = current->domain, *rd;
-    int            lport, rport = bind->remote_port;
+    int            lport, rc;
+    evtchn_port_t  rport = bind->remote_port;
     domid_t        rdom = bind->remote_dom;
-    long           rc;
 
     if ( (rd = rcu_lock_domain_by_any_id(rdom)) == NULL )
         return -ESRCH;
@@ -488,12 +487,12 @@ int evtchn_bind_virq(evtchn_bind_virq_t
 }
 
 
-static long evtchn_bind_ipi(evtchn_bind_ipi_t *bind)
+static int evtchn_bind_ipi(evtchn_bind_ipi_t *bind)
 {
     struct evtchn *chn;
     struct domain *d = current->domain;
-    int            port, vcpu = bind->vcpu;
-    long           rc = 0;
+    int            port, rc = 0;
+    unsigned int   vcpu = bind->vcpu;
 
     if ( domain_vcpu(d, vcpu) == NULL )
         return -ENOENT;
@@ -547,16 +546,16 @@ static void unlink_pirq_port(struct evtc
 }
 
 
-static long evtchn_bind_pirq(evtchn_bind_pirq_t *bind)
+static int evtchn_bind_pirq(evtchn_bind_pirq_t *bind)
 {
     struct evtchn *chn;
     struct domain *d = current->domain;
     struct vcpu   *v = d->vcpu[0];
     struct pirq   *info;
-    int            port = 0, pirq = bind->pirq;
-    long           rc;
+    int            port = 0, rc;
+    unsigned int   pirq = bind->pirq;
 
-    if ( (pirq < 0) || (pirq >= d->nr_pirqs) )
+    if ( pirq >= d->nr_pirqs )
         return -EINVAL;
 
     if ( !is_hvm_domain(d) && !pirq_access_permitted(d, pirq) )
@@ -612,7 +611,7 @@ int evtchn_close(struct domain *d1, int
 {
     struct domain *d2 = NULL;
     struct evtchn *chn1 = _evtchn_from_port(d1, port1), *chn2;
-    long           rc = 0;
+    int            rc = 0;
 
     if ( !chn1 )
         return -EINVAL;
@@ -960,7 +959,7 @@ int evtchn_status(evtchn_status_t *statu
     struct domain   *d;
     domid_t          dom = status->dom;
     struct evtchn   *chn;
-    long             rc = 0;
+    int              rc = 0;
 
     d = rcu_lock_domain_by_any_id(dom);
     if ( d == NULL )
@@ -1026,11 +1025,11 @@ int evtchn_status(evtchn_status_t *statu
 }
 
 
-long evtchn_bind_vcpu(unsigned int port, unsigned int vcpu_id)
+int evtchn_bind_vcpu(evtchn_port_t port, unsigned int vcpu_id)
 {
     struct domain *d = current->domain;
     struct evtchn *chn;
-    long           rc = 0;
+    int           rc = 0;
     struct vcpu   *v;
 
     /* Use the vcpu info to prevent speculative out-of-bound accesses */
@@ -1169,12 +1168,11 @@ int evtchn_reset(struct domain *d, bool
     return rc;
 }
 
-static long evtchn_set_priority(const struct evtchn_set_priority *set_priority)
+static int evtchn_set_priority(const struct evtchn_set_priority *set_priority)
 {
     struct domain *d = current->domain;
-    unsigned int port = set_priority->port;
-    struct evtchn *chn = _evtchn_from_port(d, port);
-    long ret;
+    struct evtchn *chn = _evtchn_from_port(d, set_priority->port);
+    int ret;
 
     if ( !chn )
         return -EINVAL;
@@ -1190,7 +1188,7 @@ static long evtchn_set_priority(const st
 
 long do_event_channel_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
 {
-    long rc;
+    int rc;
 
     switch ( cmd )
     {
--- a/xen/include/xen/event.h
+++ b/xen/include/xen/event.h
@@ -54,7 +54,7 @@ void send_guest_pirq(struct domain *, co
 int evtchn_send(struct domain *d, unsigned int lport);
 
 /* Bind a local event-channel port to the specified VCPU. */
-long evtchn_bind_vcpu(unsigned int port, unsigned int vcpu_id);
+int evtchn_bind_vcpu(evtchn_port_t port, unsigned int vcpu_id);
 
 /* Bind a VIRQ. */
 int evtchn_bind_virq(evtchn_bind_virq_t *bind, evtchn_port_t port);



  parent reply	other threads:[~2021-01-27  8:17 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-27  8:13 [PATCH v5 0/6] evtchn: (not so) recent XSAs follow-on Jan Beulich
2021-01-27  8:15 ` [PATCH v5 1/6] evtchn: use per-channel lock where possible Jan Beulich
2021-01-27  8:16 ` [PATCH v5 2/6] evtchn: convert domain event lock to an r/w one Jan Beulich
2021-05-27 11:01   ` Roger Pau Monné
2021-05-27 11:16     ` Jan Beulich
2022-07-07 18:00   ` Julien Grall
2021-01-27  8:16 ` [PATCH v5 3/6] evtchn: slightly defer lock acquire where possible Jan Beulich
2021-01-27  8:16 ` [PATCH v5 4/6] evtchn: add helper for port_is_valid() + evtchn_from_port() Jan Beulich
2021-01-27  8:17 ` Jan Beulich [this message]
2021-01-27  8:17 ` [PATCH v5 6/6] evtchn: drop acquiring of per-channel lock from send_guest_{global,vcpu}_virq() Jan Beulich
2021-04-21 15:23 ` Ping: [PATCH v5 0/6] evtchn: (not so) recent XSAs follow-on Jan Beulich
2021-04-21 15:56   ` Julien Grall
2021-04-22  8:53     ` Jan Beulich
2021-05-14 15:29       ` Roger Pau Monné
2021-05-17  7:15         ` Jan Beulich

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