diff options
| -rw-r--r-- | block/export/vduse-blk.c | 132 |
1 files changed, 93 insertions, 39 deletions
diff --git a/block/export/vduse-blk.c b/block/export/vduse-blk.c index b53ef39da0..a25556fe04 100644 --- a/block/export/vduse-blk.c +++ b/block/export/vduse-blk.c @@ -31,7 +31,8 @@ typedef struct VduseBlkExport { VduseDev *dev; uint16_t num_queues; char *recon_file; - unsigned int inflight; + unsigned int inflight; /* atomic */ + bool vqs_started; } VduseBlkExport; typedef struct VduseBlkReq { @@ -41,13 +42,24 @@ typedef struct VduseBlkReq { static void vduse_blk_inflight_inc(VduseBlkExport *vblk_exp) { - vblk_exp->inflight++; + if (qatomic_fetch_inc(&vblk_exp->inflight) == 0) { + /* Prevent export from being deleted */ + aio_context_acquire(vblk_exp->export.ctx); + blk_exp_ref(&vblk_exp->export); + aio_context_release(vblk_exp->export.ctx); + } } static void vduse_blk_inflight_dec(VduseBlkExport *vblk_exp) { - if (--vblk_exp->inflight == 0) { + if (qatomic_fetch_dec(&vblk_exp->inflight) == 1) { + /* Wake AIO_WAIT_WHILE() */ aio_wait_kick(); + + /* Now the export can be deleted */ + aio_context_acquire(vblk_exp->export.ctx); + blk_exp_unref(&vblk_exp->export); + aio_context_release(vblk_exp->export.ctx); } } @@ -124,8 +136,12 @@ static void vduse_blk_enable_queue(VduseDev *dev, VduseVirtq *vq) { VduseBlkExport *vblk_exp = vduse_dev_get_priv(dev); + if (!vblk_exp->vqs_started) { + return; /* vduse_blk_drained_end() will start vqs later */ + } + aio_set_fd_handler(vblk_exp->export.ctx, vduse_queue_get_fd(vq), - true, on_vduse_vq_kick, NULL, NULL, NULL, vq); + false, on_vduse_vq_kick, NULL, NULL, NULL, vq); /* Make sure we don't miss any kick afer reconnecting */ eventfd_write(vduse_queue_get_fd(vq), 1); } @@ -133,9 +149,14 @@ static void vduse_blk_enable_queue(VduseDev *dev, VduseVirtq *vq) static void vduse_blk_disable_queue(VduseDev *dev, VduseVirtq *vq) { VduseBlkExport *vblk_exp = vduse_dev_get_priv(dev); + int fd = vduse_queue_get_fd(vq); - aio_set_fd_handler(vblk_exp->export.ctx, vduse_queue_get_fd(vq), - true, NULL, NULL, NULL, NULL, NULL); + if (fd < 0) { + return; + } + + aio_set_fd_handler(vblk_exp->export.ctx, fd, false, + NULL, NULL, NULL, NULL, NULL); } static const VduseOps vduse_blk_ops = { @@ -152,42 +173,19 @@ static void on_vduse_dev_kick(void *opaque) static void vduse_blk_attach_ctx(VduseBlkExport *vblk_exp, AioContext *ctx) { - int i; - aio_set_fd_handler(vblk_exp->export.ctx, vduse_dev_get_fd(vblk_exp->dev), - true, on_vduse_dev_kick, NULL, NULL, NULL, + false, on_vduse_dev_kick, NULL, NULL, NULL, vblk_exp->dev); - for (i = 0; i < vblk_exp->num_queues; i++) { - VduseVirtq *vq = vduse_dev_get_queue(vblk_exp->dev, i); - int fd = vduse_queue_get_fd(vq); - - if (fd < 0) { - continue; - } - aio_set_fd_handler(vblk_exp->export.ctx, fd, true, - on_vduse_vq_kick, NULL, NULL, NULL, vq); - } + /* Virtqueues are handled by vduse_blk_drained_end() */ } static void vduse_blk_detach_ctx(VduseBlkExport *vblk_exp) { - int i; - - for (i = 0; i < vblk_exp->num_queues; i++) { - VduseVirtq *vq = vduse_dev_get_queue(vblk_exp->dev, i); - int fd = vduse_queue_get_fd(vq); - - if (fd < 0) { - continue; - } - aio_set_fd_handler(vblk_exp->export.ctx, fd, - true, NULL, NULL, NULL, NULL, NULL); - } aio_set_fd_handler(vblk_exp->export.ctx, vduse_dev_get_fd(vblk_exp->dev), - true, NULL, NULL, NULL, NULL, NULL); + false, NULL, NULL, NULL, NULL, NULL); - AIO_WAIT_WHILE(vblk_exp->export.ctx, vblk_exp->inflight > 0); + /* Virtqueues are handled by vduse_blk_drained_begin() */ } @@ -220,8 +218,55 @@ static void vduse_blk_resize(void *opaque) (char *)&config.capacity); } +static void vduse_blk_stop_virtqueues(VduseBlkExport *vblk_exp) +{ + for (uint16_t i = 0; i < vblk_exp->num_queues; i++) { + VduseVirtq *vq = vduse_dev_get_queue(vblk_exp->dev, i); + vduse_blk_disable_queue(vblk_exp->dev, vq); + } + + vblk_exp->vqs_started = false; +} + +static void vduse_blk_start_virtqueues(VduseBlkExport *vblk_exp) +{ + vblk_exp->vqs_started = true; + + for (uint16_t i = 0; i < vblk_exp->num_queues; i++) { + VduseVirtq *vq = vduse_dev_get_queue(vblk_exp->dev, i); + vduse_blk_enable_queue(vblk_exp->dev, vq); + } +} + +static void vduse_blk_drained_begin(void *opaque) +{ + BlockExport *exp = opaque; + VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export); + + vduse_blk_stop_virtqueues(vblk_exp); +} + +static void vduse_blk_drained_end(void *opaque) +{ + BlockExport *exp = opaque; + VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export); + + vduse_blk_start_virtqueues(vblk_exp); +} + +static bool vduse_blk_drained_poll(void *opaque) +{ + BlockExport *exp = opaque; + VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export); + + return qatomic_read(&vblk_exp->inflight) > 0; +} + static const BlockDevOps vduse_block_ops = { - .resize_cb = vduse_blk_resize, + .resize_cb = vduse_blk_resize, + .drained_begin = vduse_blk_drained_begin, + .drained_end = vduse_blk_drained_end, + .drained_poll = vduse_blk_drained_poll, }; static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts, @@ -268,6 +313,7 @@ static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts, vblk_exp->handler.serial = g_strdup(vblk_opts->serial ?: ""); vblk_exp->handler.logical_block_size = logical_block_size; vblk_exp->handler.writable = opts->writable; + vblk_exp->vqs_started = true; config.capacity = cpu_to_le64(blk_getlength(exp->blk) >> VIRTIO_BLK_SECTOR_BITS); @@ -322,14 +368,20 @@ static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts, vduse_dev_setup_queue(vblk_exp->dev, i, queue_size); } - aio_set_fd_handler(exp->ctx, vduse_dev_get_fd(vblk_exp->dev), true, + aio_set_fd_handler(exp->ctx, vduse_dev_get_fd(vblk_exp->dev), false, on_vduse_dev_kick, NULL, NULL, NULL, vblk_exp->dev); blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach, vblk_exp); - blk_set_dev_ops(exp->blk, &vduse_block_ops, exp); + /* + * We handle draining ourselves using an in-flight counter and by disabling + * virtqueue fd handlers. Do not queue BlockBackend requests, they need to + * complete so the in-flight counter reaches zero. + */ + blk_set_disable_request_queuing(exp->blk, true); + return 0; err: vduse_dev_destroy(vblk_exp->dev); @@ -344,6 +396,9 @@ static void vduse_blk_exp_delete(BlockExport *exp) VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export); int ret; + assert(qatomic_read(&vblk_exp->inflight) == 0); + + vduse_blk_detach_ctx(vblk_exp); blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach, vblk_exp); ret = vduse_dev_destroy(vblk_exp->dev); @@ -354,13 +409,12 @@ static void vduse_blk_exp_delete(BlockExport *exp) g_free(vblk_exp->handler.serial); } +/* Called with exp->ctx acquired */ static void vduse_blk_exp_request_shutdown(BlockExport *exp) { VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export); - aio_context_acquire(vblk_exp->export.ctx); - vduse_blk_detach_ctx(vblk_exp); - aio_context_acquire(vblk_exp->export.ctx); + vduse_blk_stop_virtqueues(vblk_exp); } const BlockExportDriver blk_exp_vduse_blk = { |