From 235e59cf03ed75d0ce96c97343194ed11c146231 Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@redhat.com>
Date: Tue, 7 Jul 2020 18:05:42 +0200
Subject: qemu-option: Use returned bool to check for failure

The previous commit enables conversion of

    foo(..., &err);
    if (err) {
        ...
    }

to

    if (!foo(..., &err)) {
        ...
    }

for QemuOpts functions that now return true / false on success /
error.  Coccinelle script:

    @@
    identifier fun = {
        opts_do_parse, parse_option_bool, parse_option_number,
        parse_option_size, qemu_opt_parse, qemu_opt_rename, qemu_opt_set,
        qemu_opt_set_bool, qemu_opt_set_number, qemu_opts_absorb_qdict,
        qemu_opts_do_parse, qemu_opts_from_qdict_entry, qemu_opts_set,
        qemu_opts_validate
    };
    expression list args, args2;
    typedef Error;
    Error *err;
    @@
    -    fun(args, &err, args2);
    -    if (err)
    +    if (!fun(args, &err, args2))
         {
             ...
         }

A few line breaks tidied up manually.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200707160613.848843-15-armbru@redhat.com>
[Conflict with commit 0b6786a9c1 "block/amend: refactor qcow2 amend
options" resolved by rerunning Coccinelle on master's version]
---
 tpm.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'tpm.c')

diff --git a/tpm.c b/tpm.c
index 9c9e20b..75bc937 100644
--- a/tpm.c
+++ b/tpm.c
@@ -116,8 +116,7 @@ static int tpm_init_tpmdev(void *dummy, QemuOpts *opts, Error **errp)
     }
 
     /* validate backend specific opts */
-    qemu_opts_validate(opts, be->opts, &local_err);
-    if (local_err) {
+    if (!qemu_opts_validate(opts, be->opts, &local_err)) {
         error_propagate(errp, local_err);
         return 1;
     }
-- 
cgit v1.1


From 668f62ec621e4e2919fb7d4caa5d805764c5852d Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@redhat.com>
Date: Tue, 7 Jul 2020 18:06:02 +0200
Subject: 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>
---
 tpm.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

(limited to 'tpm.c')

diff --git a/tpm.c b/tpm.c
index 75bc937..fe03b24 100644
--- a/tpm.c
+++ b/tpm.c
@@ -85,7 +85,6 @@ static int tpm_init_tpmdev(void *dummy, QemuOpts *opts, Error **errp)
     const char *id;
     const TPMBackendClass *be;
     TPMBackend *drv;
-    Error *local_err = NULL;
     int i;
 
     if (!QLIST_EMPTY(&tpm_backends)) {
@@ -116,8 +115,7 @@ static int tpm_init_tpmdev(void *dummy, QemuOpts *opts, Error **errp)
     }
 
     /* validate backend specific opts */
-    if (!qemu_opts_validate(opts, be->opts, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qemu_opts_validate(opts, be->opts, errp)) {
         return 1;
     }
 
-- 
cgit v1.1