xemu/block
Markus Armbruster 668f62ec62 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>
2020-07-10 15:18:08 +02:00
..
monitor blockdev: Split off basic bitmap operations for qemu-img 2020-05-19 10:32:14 -05:00
accounting.c block: add empty account cookie type 2019-10-10 10:56:18 +02:00
aio_task.c block: introduce aio task pool 2019-10-10 10:56:17 +02:00
amend.c block/core: add generic infrastructure for x-blockdev-amend qmp command 2020-07-06 08:49:28 +02:00
backup-top.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
backup-top.h block: introduce backup-top filter driver 2019-10-10 10:56:18 +02:00
backup.c backup: Make sure that source and target size match 2020-05-08 13:26:35 +02:00
blkdebug.c qapi: Use returned bool to check for failure, Coccinelle part 2020-07-10 15:18:08 +02:00
blklogwrites.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
blkreplay.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
blkverify.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
block-backend.c block: Pass BdrvChildRole in remaining cases 2020-05-18 19:05:25 +02:00
block-copy.c block/block-copy: block_copy_dirty_clusters: fix failure check 2020-07-06 08:33:06 +02:00
bochs.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
cloop.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
commit.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
copy-on-read.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
create.c block/create: Do not abort if a block driver is not available 2019-09-13 12:18:37 +02:00
crypto.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
crypto.h block/crypto: implement the encryption key management 2020-07-06 08:49:28 +02:00
curl.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
dirty-bitmap.c block/dirty-bitmap: add bdrv_has_named_bitmaps helper 2020-05-28 13:15:22 -05:00
dmg-bz2.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
dmg-lzfse.c block: adding lzfse decompressing support as a module. 2018-12-14 11:52:40 +01:00
dmg.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
dmg.h Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
file-posix.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
file-win32.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
filter-compress.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
gluster.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
io_uring.c io_uring: use io_uring_cq_ready() to check for ready cqes 2020-06-05 09:54:48 +01:00
io.c block: drop unallocated_blocks_are_zero 2020-07-06 10:34:14 +02:00
iscsi-opts.c Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
iscsi.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
linux-aio.c misc: Replace zero-length arrays with flexible array member (automatic) 2020-03-16 22:07:42 +01:00
Makefile.objs block/core: add generic infrastructure for x-blockdev-amend qmp command 2020-07-06 08:49:28 +02:00
mirror.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
nbd.c qapi: Use returned bool to check for failure, Coccinelle part 2020-07-10 15:18:08 +02:00
nfs.c block: Drop unused .bdrv_has_zero_init_truncate 2020-05-08 13:26:35 +02:00
null.c replay: add BH oneshot event for block layer 2019-10-14 17:12:48 +02:00
nvme.c block/nvme: support nested aio_poll() 2020-06-23 15:46:08 +01:00
parallels.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
parallels.h Clean up includes 2018-02-09 05:05:11 +01:00
qapi-sysemu.c block: Move system emulator QMP commands to block/qapi-sysemu.c 2020-03-06 17:15:38 +01:00
qapi.c block: Fix VM size field width in snapshot dump 2020-02-20 16:43:42 +01:00
qcow2-bitmap.c qcow2: Tweak comments on qcow2_get_persistent_dirty_bitmap_size 2020-06-17 14:53:39 +02:00
qcow2-cache.c core: replace getpagesize() with qemu_real_host_page_size 2019-10-26 15:38:06 +02:00
qcow2-cluster.c qcow2: Support BDRV_REQ_ZERO_WRITE for truncate 2020-04-30 17:51:07 +02:00
qcow2-refcount.c block: Comment cleanups 2020-05-05 13:17:36 +02:00
qcow2-snapshot.c qcow2: Allow resize of images with internal snapshots 2020-05-05 13:17:36 +02:00
qcow2-threads.c qcow2: add zstd cluster compression 2020-05-13 14:20:31 +02:00
qcow2.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
qcow2.h qcow2: Expose bitmaps' size during measure 2020-05-28 13:16:16 -05:00
qcow.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
qed-check.c block/qed: add missed coroutine_fn markers 2019-04-30 15:29:00 +02:00
qed-cluster.c qed: protect table cache with CoMutex 2017-07-17 11:34:11 +08:00
qed-l2-cache.c qed: protect table cache with CoMutex 2017-07-17 11:34:11 +08:00
qed-table.c block/qed: add missed coroutine_fn markers 2019-04-30 15:29:00 +02:00
qed.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
qed.h qed: Simplify backing reads 2020-07-06 10:34:14 +02:00
quorum.c error: Avoid unnecessary error_propagate() after error_setg() 2020-07-10 15:18:08 +02:00
raw-format.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
rbd.c block: Drop unused .bdrv_has_zero_init_truncate 2020-05-08 13:26:35 +02:00
replication.c error: Avoid unnecessary error_propagate() after error_setg() 2020-07-10 15:18:08 +02:00
sheepdog.c qapi: Use returned bool to check for failure, Coccinelle part 2020-07-10 15:18:08 +02:00
snapshot.c block/snapshot: rename Error ** parameter to more common errp 2019-12-18 08:43:19 +01:00
ssh.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
stream.c block/stream: Remove redundant statement in stream_run() 2020-03-09 15:59:31 +01:00
throttle-groups.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
throttle.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
trace-events block/nvme: support nested aio_poll() 2020-06-23 15:46:08 +01:00
vdi.c block/vdi: return ZERO block-status when appropriate 2020-07-06 08:49:28 +02:00
vhdx-endian.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
vhdx-log.c block: Add flags to bdrv(_co)_truncate() 2020-04-30 17:51:07 +02:00
vhdx.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
vhdx.h block/vhdx: Use IEC binary prefixes for size constants 2019-04-30 15:29:00 +02:00
vmdk.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
vpc.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
vvfat.c qemu-option: Use returned bool to check for failure 2020-07-10 15:17:35 +02:00
vxhs.c error: Avoid unnecessary error_propagate() after error_setg() 2020-07-10 15:18:08 +02:00
win32-aio.c Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
write-threshold.c qapi: Drop qapi_event_send_FOO()'s Error ** argument 2018-08-28 18:21:38 +02:00