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authorMarkus Armbruster <armbru@redhat.com>2020-07-07 18:06:02 +0200
committerMarkus Armbruster <armbru@redhat.com>2020-07-10 15:18:08 +0200
commit668f62ec621e4e2919fb7d4caa5d805764c5852d (patch)
tree8cb4b78b9ab596b0eb573a0cae77ac1893456826 /net/dump.c
parentdcfe480544eef72d666cb1695624449e2c22da2d (diff)
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error: Eliminate error_propagate() with Coccinelle, part 1
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>
Diffstat (limited to 'net/dump.c')
-rw-r--r--net/dump.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/net/dump.c b/net/dump.c
index f7a302f..11a737a 100644
--- a/net/dump.c
+++ b/net/dump.c
@@ -192,11 +192,9 @@ static void filter_dump_set_maxlen(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
NetFilterDumpState *nfds = FILTER_DUMP(obj);
- Error *local_err = NULL;
uint32_t value;
- if (!visit_type_uint32(v, name, &value, &local_err)) {
- error_propagate(errp, local_err);
+ if (!visit_type_uint32(v, name, &value, errp)) {
return;
}
if (value == 0) {