Pull request

* Gracefully handle Linux AIO init failure
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Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging

Pull request

 * Gracefully handle Linux AIO init failure

# gpg: Signature made Wed 27 Jun 2018 15:48:28 BST
# gpg:                using RSA key 9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/block-pull-request:
  linux-aio: properly bubble up errors from initialization
  compiler: add a sizeof_field() macro

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

accel/tcg/translate-all.c

@@ -191,7 +191,7 @@ struct page_collection {
 
 /* Make sure all possible CPU event bits fit in tb->trace_vcpu_dstate */
 QEMU_BUILD_BUG_ON(CPU_TRACE_DSTATE_MAX_EVENTS >
-                  sizeof(((TranslationBlock *)0)->trace_vcpu_dstate)
+                  sizeof_field(TranslationBlock, trace_vcpu_dstate)
                   * BITS_PER_BYTE);
 
 /*

block/file-posix.c

@@ -545,11 +545,17 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
 
 #ifdef CONFIG_LINUX_AIO
      /* Currently Linux does AIO only for files opened with O_DIRECT */
-    if (s->use_linux_aio && !(s->open_flags & O_DIRECT)) {
-        error_setg(errp, "aio=native was specified, but it requires "
-                         "cache.direct=on, which was not specified.");
-        ret = -EINVAL;
-        goto fail;
+    if (s->use_linux_aio) {
+        if (!(s->open_flags & O_DIRECT)) {
+            error_setg(errp, "aio=native was specified, but it requires "
+                             "cache.direct=on, which was not specified.");
+            ret = -EINVAL;
+            goto fail;
+        }
+        if (!aio_setup_linux_aio(bdrv_get_aio_context(bs), errp)) {
+            error_prepend(errp, "Unable to use native AIO: ");
+            goto fail;
+        }
     }
 #else
     if (s->use_linux_aio) {
@@ -1723,6 +1729,22 @@ static BlockAIOCB *raw_aio_flush(BlockDriverState *bs,
     return paio_submit(bs, s->fd, 0, NULL, 0, cb, opaque, QEMU_AIO_FLUSH);
 }
 
+static void raw_aio_attach_aio_context(BlockDriverState *bs,
+                                       AioContext *new_context)
+{
+#ifdef CONFIG_LINUX_AIO
+    BDRVRawState *s = bs->opaque;
+    if (s->use_linux_aio) {
+        Error *local_err;
+        if (!aio_setup_linux_aio(new_context, &local_err)) {
+            error_reportf_err(local_err, "Unable to use native AIO, "
+                                         "falling back to thread pool: ");
+            s->use_linux_aio = false;
+        }
+    }
+#endif
+}
+
 static void raw_close(BlockDriverState *bs)
 {
     BDRVRawState *s = bs->opaque;
@@ -2601,6 +2623,7 @@ BlockDriver bdrv_file = {
     .bdrv_refresh_limits = raw_refresh_limits,
     .bdrv_io_plug = raw_aio_plug,
     .bdrv_io_unplug = raw_aio_unplug,
+    .bdrv_attach_aio_context = raw_aio_attach_aio_context,
 
     .bdrv_truncate = raw_truncate,
     .bdrv_getlength = raw_getlength,

block/linux-aio.c

@@ -15,6 +15,7 @@
 #include "block/raw-aio.h"
 #include "qemu/event_notifier.h"
 #include "qemu/coroutine.h"
+#include "qapi/error.h"
 
 #include <libaio.h>
 
@@ -470,16 +471,21 @@ void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context)
                            qemu_laio_poll_cb);
 }
 
-LinuxAioState *laio_init(void)
+LinuxAioState *laio_init(Error **errp)
 {
+    int rc;
     LinuxAioState *s;
 
     s = g_malloc0(sizeof(*s));
-    if (event_notifier_init(&s->e, false) < 0) {
+    rc = event_notifier_init(&s->e, false);
+    if (rc < 0) {
+        error_setg_errno(errp, -rc, "failed to to initialize event notifier");
         goto out_free_state;
     }
 
-    if (io_setup(MAX_EVENTS, &s->ctx) != 0) {
+    rc = io_setup(MAX_EVENTS, &s->ctx);
+    if (rc < 0) {
+        error_setg_errno(errp, -rc, "failed to create linux AIO context");
         goto out_close_efd;
     }
 

hw/display/xenfb.c

@@ -525,8 +525,8 @@ static int xenfb_configure_fb(struct XenFB *xenfb, size_t fb_len_lim,
                               int width, int height, int depth,
                               size_t fb_len, int offset, int row_stride)
 {
-    size_t mfn_sz = sizeof(*((struct xenfb_page *)0)->pd);
-    size_t pd_len = sizeof(((struct xenfb_page *)0)->pd) / mfn_sz;
+    size_t mfn_sz = sizeof_field(struct xenfb_page, pd[0]);
+    size_t pd_len = sizeof_field(struct xenfb_page, pd) / mfn_sz;
     size_t fb_pages = pd_len * XC_PAGE_SIZE / mfn_sz;
     size_t fb_len_max = fb_pages * XC_PAGE_SIZE;
     int max_width, max_height;

hw/net/rocker/rocker_of_dpa.c

@@ -104,7 +104,7 @@ typedef struct of_dpa_flow_key {
 
 /* Width of key which includes field 'f' in u64s, rounded up */
 #define FLOW_KEY_WIDTH(f) \
-    DIV_ROUND_UP(offsetof(OfDpaFlowKey, f) + sizeof(((OfDpaFlowKey *)0)->f), \
+    DIV_ROUND_UP(offsetof(OfDpaFlowKey, f) + sizeof_field(OfDpaFlowKey, f), \
     sizeof(uint64_t))
 
 typedef struct of_dpa_flow_action {

hw/net/virtio-net.c

@@ -46,7 +46,7 @@
  * 'container'.
  */
 #define endof(container, field) \
-    (offsetof(container, field) + sizeof(((container *)0)->field))
+    (offsetof(container, field) + sizeof_field(container, field))
 
 typedef struct VirtIOFeature {
     uint64_t flags;

include/block/aio.h

@@ -381,6 +381,9 @@ GSource *aio_get_g_source(AioContext *ctx);
 /* Return the ThreadPool bound to this AioContext */
 struct ThreadPool *aio_get_thread_pool(AioContext *ctx);
 
+/* Setup the LinuxAioState bound to this AioContext */
+struct LinuxAioState *aio_setup_linux_aio(AioContext *ctx, Error **errp);
+
 /* Return the LinuxAioState bound to this AioContext */
 struct LinuxAioState *aio_get_linux_aio(AioContext *ctx);
 

include/block/raw-aio.h

@@ -43,7 +43,7 @@
 /* linux-aio.c - Linux native implementation */
 #ifdef CONFIG_LINUX_AIO
 typedef struct LinuxAioState LinuxAioState;
-LinuxAioState *laio_init(void);
+LinuxAioState *laio_init(Error **errp);
 void laio_cleanup(LinuxAioState *s);
 int coroutine_fn laio_co_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
                                 uint64_t offset, QEMUIOVector *qiov, int type);

include/hw/xen/io/ring.h

@@ -65,7 +65,7 @@ typedef unsigned int RING_IDX;
  */
 #define __CONST_RING_SIZE(_s, _sz) \
     (__RD32(((_sz) - offsetof(struct _s##_sring, ring)) / \
-	    sizeof(((struct _s##_sring *)0)->ring[0])))
+            sizeof_field(struct _s##_sring, ring[0])))
 /*
  * The same for passing in an actual pointer instead of a name tag.
  */

include/qemu/compiler.h

@@ -64,6 +64,8 @@
         (type *) ((char *) __mptr - offsetof(type, member));})
 #endif
 
+#define sizeof_field(type, field) sizeof(((type *)0)->field)
+
 /* Convert from a base type to a parent type, with compile time checking.  */
 #ifdef __GNUC__
 #define DO_UPCAST(type, field, dev) ( __extension__ ( { \

stubs/linux-aio.c

@@ -21,7 +21,7 @@ void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context)
     abort();
 }
 
-LinuxAioState *laio_init(void)
+LinuxAioState *laio_init(Error **errp)
 {
     abort();
 }

target/i386/kvm.c

@@ -1533,7 +1533,7 @@ static int kvm_put_fpu(X86CPU *cpu)
 #define XSAVE_PKRU        672
 
 #define XSAVE_BYTE_OFFSET(word_offset) \
-    ((word_offset) * sizeof(((struct kvm_xsave *)0)->region[0]))
+    ((word_offset) * sizeof_field(struct kvm_xsave, region[0]))
 
 #define ASSERT_OFFSET(word_offset, field) \
     QEMU_BUILD_BUG_ON(XSAVE_BYTE_OFFSET(word_offset) != \

target/ppc/arch_dump.c

@@ -210,11 +210,11 @@ static const struct NoteFuncDescStruct {
     int contents_size;
     void (*note_contents_func)(NoteFuncArg *arg, PowerPCCPU *cpu);
 } note_func[] = {
-    {sizeof(((Note *)0)->contents.prstatus),  ppc_write_elf_prstatus},
-    {sizeof(((Note *)0)->contents.fpregset),  ppc_write_elf_fpregset},
-    {sizeof(((Note *)0)->contents.vmxregset), ppc_write_elf_vmxregset},
-    {sizeof(((Note *)0)->contents.vsxregset), ppc_write_elf_vsxregset},
-    {sizeof(((Note *)0)->contents.speregset), ppc_write_elf_speregset},
+    {sizeof_field(Note, contents.prstatus),  ppc_write_elf_prstatus},
+    {sizeof_field(Note, contents.fpregset),  ppc_write_elf_fpregset},
+    {sizeof_field(Note, contents.vmxregset), ppc_write_elf_vmxregset},
+    {sizeof_field(Note, contents.vsxregset), ppc_write_elf_vsxregset},
+    {sizeof_field(Note, contents.speregset), ppc_write_elf_speregset},
     { 0, NULL}
 };
 

target/s390x/arch_dump.c

@@ -184,20 +184,20 @@ typedef struct NoteFuncDescStruct {
 } NoteFuncDesc;
 
 static const NoteFuncDesc note_core[] = {
-    {sizeof(((Note *)0)->contents.prstatus), s390x_write_elf64_prstatus},
-    {sizeof(((Note *)0)->contents.fpregset), s390x_write_elf64_fpregset},
+    {sizeof_field(Note, contents.prstatus), s390x_write_elf64_prstatus},
+    {sizeof_field(Note, contents.fpregset), s390x_write_elf64_fpregset},
     { 0, NULL}
 };
 
 static const NoteFuncDesc note_linux[] = {
-    {sizeof(((Note *)0)->contents.prefix),   s390x_write_elf64_prefix},
-    {sizeof(((Note *)0)->contents.ctrs),     s390x_write_elf64_ctrs},
-    {sizeof(((Note *)0)->contents.timer),    s390x_write_elf64_timer},
-    {sizeof(((Note *)0)->contents.todcmp),   s390x_write_elf64_todcmp},
-    {sizeof(((Note *)0)->contents.todpreg),  s390x_write_elf64_todpreg},
-    {sizeof(((Note *)0)->contents.vregslo),  s390x_write_elf64_vregslo},
-    {sizeof(((Note *)0)->contents.vregshi),  s390x_write_elf64_vregshi},
-    {sizeof(((Note *)0)->contents.gscb),     s390x_write_elf64_gscb},
+    {sizeof_field(Note, contents.prefix),   s390x_write_elf64_prefix},
+    {sizeof_field(Note, contents.ctrs),     s390x_write_elf64_ctrs},
+    {sizeof_field(Note, contents.timer),    s390x_write_elf64_timer},
+    {sizeof_field(Note, contents.todcmp),   s390x_write_elf64_todcmp},
+    {sizeof_field(Note, contents.todpreg),  s390x_write_elf64_todpreg},
+    {sizeof_field(Note, contents.vregslo),  s390x_write_elf64_vregslo},
+    {sizeof_field(Note, contents.vregshi),  s390x_write_elf64_vregshi},
+    {sizeof_field(Note, contents.gscb),     s390x_write_elf64_gscb},
     { 0, NULL}
 };
 

util/async.c

@@ -323,14 +323,22 @@ ThreadPool *aio_get_thread_pool(AioContext *ctx)
 }
 
 #ifdef CONFIG_LINUX_AIO
-LinuxAioState *aio_get_linux_aio(AioContext *ctx)
+LinuxAioState *aio_setup_linux_aio(AioContext *ctx, Error **errp)
 {
     if (!ctx->linux_aio) {
-        ctx->linux_aio = laio_init();
-        laio_attach_aio_context(ctx->linux_aio, ctx);
+        ctx->linux_aio = laio_init(errp);
+        if (ctx->linux_aio) {
+            laio_attach_aio_context(ctx->linux_aio, ctx);
+        }
     }
     return ctx->linux_aio;
 }
+
+LinuxAioState *aio_get_linux_aio(AioContext *ctx)
+{
+    assert(ctx->linux_aio);
+    return ctx->linux_aio;
+}
 #endif
 
 void aio_notify(AioContext *ctx)