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>

7 files changed, 25 insertions, 58 deletions

diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
index 97fa970e72..5448d101d9 100644
--- a/hw/ppc/e500.c
+++ b/hw/ppc/e500.c
@@ -764,15 +764,13 @@ static DeviceState *ppce500_init_mpic_qemu(PPCE500MachineState *pms,
 static DeviceState *ppce500_init_mpic_kvm(const PPCE500MachineClass *pmc,
                                           IrqLines *irqs, Error **errp)
 {
-    Error *err = NULL;
     DeviceState *dev;
     CPUState *cs;
 
     dev = qdev_new(TYPE_KVM_OPENPIC);
     qdev_prop_set_uint32(dev, "model", pmc->mpic_version);
 
-    if (!sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &err)) {
-        error_propagate(errp, err);
+    if (!sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), errp)) {
         object_unparent(OBJECT(dev));
         return NULL;
     }
diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index 194b457917..6670967e26 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -1140,8 +1140,7 @@ static void pnv_chip_power8_realize(DeviceState *dev, Error **errp)
                             &error_fatal);
     object_property_set_link(OBJECT(&chip8->psi), ICS_PROP_XICS,
                              OBJECT(chip8->xics), &error_abort);
-    if (!qdev_realize(DEVICE(&chip8->psi), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(&chip8->psi), NULL, errp)) {
         return;
     }
     pnv_xscom_add_subregion(chip, PNV_XSCOM_PSIHB_BASE,
@@ -1170,8 +1169,7 @@ static void pnv_chip_power8_realize(DeviceState *dev, Error **errp)
     /* Create the simplified OCC model */
     object_property_set_link(OBJECT(&chip8->occ), "psi", OBJECT(&chip8->psi),
                              &error_abort);
-    if (!qdev_realize(DEVICE(&chip8->occ), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(&chip8->occ), NULL, errp)) {
         return;
     }
     pnv_xscom_add_subregion(chip, PNV_XSCOM_OCC_BASE, &chip8->occ.xscom_regs);
@@ -1183,8 +1181,7 @@ static void pnv_chip_power8_realize(DeviceState *dev, Error **errp)
     /* HOMER */
     object_property_set_link(OBJECT(&chip8->homer), "chip", OBJECT(chip),
                              &error_abort);
-    if (!qdev_realize(DEVICE(&chip8->homer), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(&chip8->homer), NULL, errp)) {
         return;
     }
     /* Homer Xscom region */
@@ -1202,8 +1199,7 @@ static void pnv_chip_power8_realize(DeviceState *dev, Error **errp)
         object_property_set_int(OBJECT(phb), "index", i, &error_fatal);
         object_property_set_int(OBJECT(phb), "chip-id", chip->chip_id,
                                 &error_fatal);
-        if (!sysbus_realize(SYS_BUS_DEVICE(phb), &local_err)) {
-            error_propagate(errp, local_err);
+        if (!sysbus_realize(SYS_BUS_DEVICE(phb), errp)) {
             return;
         }
 
@@ -1358,7 +1354,6 @@ static void pnv_chip_quad_realize(Pnv9Chip *chip9, Error **errp)
 static void pnv_chip_power9_phb_realize(PnvChip *chip, Error **errp)
 {
     Pnv9Chip *chip9 = PNV9_CHIP(chip);
-    Error *local_err = NULL;
     int i, j;
     int phb_id = 0;
 
@@ -1380,8 +1375,7 @@ static void pnv_chip_power9_phb_realize(PnvChip *chip, Error **errp)
                                 &error_fatal);
         object_property_set_link(OBJECT(pec), "system-memory",
                                  OBJECT(get_system_memory()), &error_abort);
-        if (!qdev_realize(DEVICE(pec), NULL, &local_err)) {
-            error_propagate(errp, local_err);
+        if (!qdev_realize(DEVICE(pec), NULL, errp)) {
             return;
         }
 
@@ -1405,8 +1399,7 @@ static void pnv_chip_power9_phb_realize(PnvChip *chip, Error **errp)
                                     &error_fatal);
             object_property_set_link(obj, "stack", OBJECT(stack),
                                      &error_abort);
-            if (!sysbus_realize(SYS_BUS_DEVICE(obj), &local_err)) {
-                error_propagate(errp, local_err);
+            if (!sysbus_realize(SYS_BUS_DEVICE(obj), errp)) {
                 return;
             }
 
@@ -1464,8 +1457,7 @@ static void pnv_chip_power9_realize(DeviceState *dev, Error **errp)
                             PNV9_XIVE_TM_BASE(chip), &error_fatal);
     object_property_set_link(OBJECT(&chip9->xive), "chip", OBJECT(chip),
                              &error_abort);
-    if (!sysbus_realize(SYS_BUS_DEVICE(&chip9->xive), &local_err)) {
-        error_propagate(errp, local_err);
+    if (!sysbus_realize(SYS_BUS_DEVICE(&chip9->xive), errp)) {
         return;
     }
     pnv_xscom_add_subregion(chip, PNV9_XSCOM_XIVE_BASE,
@@ -1474,8 +1466,7 @@ static void pnv_chip_power9_realize(DeviceState *dev, Error **errp)
     /* Processor Service Interface (PSI) Host Bridge */
     object_property_set_int(OBJECT(&chip9->psi), "bar", PNV9_PSIHB_BASE(chip),
                             &error_fatal);
-    if (!qdev_realize(DEVICE(&chip9->psi), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(&chip9->psi), NULL, errp)) {
         return;
     }
     pnv_xscom_add_subregion(chip, PNV9_XSCOM_PSIHB_BASE,
@@ -1484,8 +1475,7 @@ static void pnv_chip_power9_realize(DeviceState *dev, Error **errp)
     /* LPC */
     object_property_set_link(OBJECT(&chip9->lpc), "psi", OBJECT(&chip9->psi),
                              &error_abort);
-    if (!qdev_realize(DEVICE(&chip9->lpc), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(&chip9->lpc), NULL, errp)) {
         return;
     }
     memory_region_add_subregion(get_system_memory(), PNV9_LPCM_BASE(chip),
@@ -1497,8 +1487,7 @@ static void pnv_chip_power9_realize(DeviceState *dev, Error **errp)
     /* Create the simplified OCC model */
     object_property_set_link(OBJECT(&chip9->occ), "psi", OBJECT(&chip9->psi),
                              &error_abort);
-    if (!qdev_realize(DEVICE(&chip9->occ), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(&chip9->occ), NULL, errp)) {
         return;
     }
     pnv_xscom_add_subregion(chip, PNV9_XSCOM_OCC_BASE, &chip9->occ.xscom_regs);
@@ -1510,8 +1499,7 @@ static void pnv_chip_power9_realize(DeviceState *dev, Error **errp)
     /* HOMER */
     object_property_set_link(OBJECT(&chip9->homer), "chip", OBJECT(chip),
                              &error_abort);
-    if (!qdev_realize(DEVICE(&chip9->homer), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(&chip9->homer), NULL, errp)) {
         return;
     }
     /* Homer Xscom region */
@@ -1591,8 +1579,7 @@ static void pnv_chip_power10_realize(DeviceState *dev, Error **errp)
     /* Processor Service Interface (PSI) Host Bridge */
     object_property_set_int(OBJECT(&chip10->psi), "bar",
                             PNV10_PSIHB_BASE(chip), &error_fatal);
-    if (!qdev_realize(DEVICE(&chip10->psi), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(&chip10->psi), NULL, errp)) {
         return;
     }
     pnv_xscom_add_subregion(chip, PNV10_XSCOM_PSIHB_BASE,
@@ -1601,8 +1588,7 @@ static void pnv_chip_power10_realize(DeviceState *dev, Error **errp)
     /* LPC */
     object_property_set_link(OBJECT(&chip10->lpc), "psi",
                              OBJECT(&chip10->psi), &error_abort);
-    if (!qdev_realize(DEVICE(&chip10->lpc), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(&chip10->lpc), NULL, errp)) {
         return;
     }
     memory_region_add_subregion(get_system_memory(), PNV10_LPCM_BASE(chip),
diff --git a/hw/ppc/pnv_core.c b/hw/ppc/pnv_core.c
index d699f077ad..4724ddf96c 100644
--- a/hw/ppc/pnv_core.c
+++ b/hw/ppc/pnv_core.c
@@ -173,8 +173,7 @@ static void pnv_core_cpu_realize(PnvCore *pc, PowerPCCPU *cpu, Error **errp)
     Error *local_err = NULL;
     PnvChipClass *pcc = PNV_CHIP_GET_CLASS(pc->chip);
 
-    if (!qdev_realize(DEVICE(cpu), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(cpu), NULL, errp)) {
         return;
     }
 
diff --git a/hw/ppc/pnv_psi.c b/hw/ppc/pnv_psi.c
index 604788a8eb..5bdeec700e 100644
--- a/hw/ppc/pnv_psi.c
+++ b/hw/ppc/pnv_psi.c
@@ -501,17 +501,14 @@ static void pnv_psi_power8_realize(DeviceState *dev, Error **errp)
 {
     PnvPsi *psi = PNV_PSI(dev);
     ICSState *ics = &PNV8_PSI(psi)->ics;
-    Error *err = NULL;
     unsigned int i;
 
     /* Create PSI interrupt control source */
     if (!object_property_set_int(OBJECT(ics), "nr-irqs", PSI_NUM_INTERRUPTS,
-                                 &err)) {
-        error_propagate(errp, err);
+                                 errp)) {
         return;
     }
-    if (!qdev_realize(DEVICE(ics), NULL, &err)) {
-        error_propagate(errp, err);
+    if (!qdev_realize(DEVICE(ics), NULL, errp)) {
         return;
     }
 
@@ -841,7 +838,6 @@ static void pnv_psi_power9_realize(DeviceState *dev, Error **errp)
 {
     PnvPsi *psi = PNV_PSI(dev);
     XiveSource *xsrc = &PNV9_PSI(psi)->source;
-    Error *local_err = NULL;
     int i;
 
     /* This is the only device with 4k ESB pages */
@@ -849,8 +845,7 @@ static void pnv_psi_power9_realize(DeviceState *dev, Error **errp)
     object_property_set_int(OBJECT(xsrc), "nr-irqs", PSIHB9_NUM_IRQS,
                             &error_fatal);
     object_property_set_link(OBJECT(xsrc), "xive", OBJECT(psi), &error_abort);
-    if (!qdev_realize(DEVICE(xsrc), NULL, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qdev_realize(DEVICE(xsrc), NULL, errp)) {
         return;
     }
 
diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
index 52be86e49c..3225fc5a2e 100644
--- a/hw/ppc/spapr_caps.c
+++ b/hw/ppc/spapr_caps.c
@@ -86,10 +86,8 @@ static void spapr_cap_set_bool(Object *obj, Visitor *v, const char *name,
     SpaprCapabilityInfo *cap = opaque;
     SpaprMachineState *spapr = SPAPR_MACHINE(obj);
     bool value;
-    Error *local_err = NULL;
 
-    if (!visit_type_bool(v, name, &value, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_bool(v, name, &value, errp)) {
         return;
     }
 
@@ -122,12 +120,10 @@ static void spapr_cap_set_string(Object *obj, Visitor *v, const char *name,
 {
     SpaprCapabilityInfo *cap = opaque;
     SpaprMachineState *spapr = SPAPR_MACHINE(obj);
-    Error *local_err = NULL;
     uint8_t i;
     char *val;
 
-    if (!visit_type_str(v, name, &val, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_str(v, name, &val, errp)) {
         return;
     }
 
@@ -167,10 +163,8 @@ static void spapr_cap_set_pagesize(Object *obj, Visitor *v, const char *name,
     SpaprMachineState *spapr = SPAPR_MACHINE(obj);
     uint64_t pagesize;
     uint8_t val;
-    Error *local_err = NULL;
 
-    if (!visit_type_size(v, name, &pagesize, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_size(v, name, &pagesize, errp)) {
         return;
     }
 
diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
index 1f18b79348..43d12bc33a 100644
--- a/hw/ppc/spapr_drc.c
+++ b/hw/ppc/spapr_drc.c
@@ -327,8 +327,7 @@ static void prop_get_fdt(Object *obj, Visitor *v, const char *name,
         case FDT_BEGIN_NODE:
             fdt_depth++;
             name = fdt_get_name(fdt, fdt_offset, &name_len);
-            if (!visit_start_struct(v, name, NULL, 0, &err)) {
-                error_propagate(errp, err);
+            if (!visit_start_struct(v, name, NULL, 0, errp)) {
                 return;
             }
             break;
@@ -347,14 +346,12 @@ static void prop_get_fdt(Object *obj, Visitor *v, const char *name,
             int i;
             prop = fdt_get_property_by_offset(fdt, fdt_offset, &prop_len);
             name = fdt_string(fdt, fdt32_to_cpu(prop->nameoff));
-            if (!visit_start_list(v, name, NULL, 0, &err)) {
-                error_propagate(errp, err);
+            if (!visit_start_list(v, name, NULL, 0, errp)) {
                 return;
             }
             for (i = 0; i < prop_len; i++) {
                 if (!visit_type_uint8(v, NULL, (uint8_t *)&prop->data[i],
-                                      &err)) {
-                    error_propagate(errp, err);
+                                      errp)) {
                     return;
                 }
             }
diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
index eb55171d70..2f8f7d62f8 100644
--- a/hw/ppc/spapr_irq.c
+++ b/hw/ppc/spapr_irq.c
@@ -302,7 +302,6 @@ void spapr_irq_init(SpaprMachineState *spapr, Error **errp)
     spapr_irq_msi_init(spapr);
 
     if (spapr->irq->xics) {
-        Error *local_err = NULL;
         Object *obj;
 
         obj = object_new(TYPE_ICS_SPAPR);
@@ -311,8 +310,7 @@ void spapr_irq_init(SpaprMachineState *spapr, Error **errp)
         object_property_set_link(obj, ICS_PROP_XICS, OBJECT(spapr),
                                  &error_abort);
         object_property_set_int(obj, "nr-irqs", smc->nr_xirqs, &error_abort);
-        if (!qdev_realize(DEVICE(obj), NULL, &local_err)) {
-            error_propagate(errp, local_err);
+        if (!qdev_realize(DEVICE(obj), NULL, errp)) {
             return;
         }