search for: blk_sts_dev_resource

Two patches are handling new edge cases introduced by doing DMA mappings (which can fail) in virtio core. I stumbled upon this while stress testing I/O for Protected Virtual Machines. I deliberately chose a tiny swiotlb size and have generated load with fio. With more than one virtio-blk disk in use I experienced hangs. The goal of this series is to fix those hangs. Halil Pasic (2):

Two patches are handling new edge cases introduced by doing DMA mappings (which can fail) in virtio core. I stumbled upon this while stress testing I/O for Protected Virtual Machines. I deliberately chose a tiny swiotlb size and have generated load with fio. With more than one virtio-blk disk in use I experienced hangs. The goal of this series is to fix those hangs. Halil Pasic (2):

From: Halil Pasic <pasic at linux.ibm.com> [ Upstream commit 3d973b2e9a625996ee997c7303cd793b9d197c65 ] Let's change the mapping between virtqueue_add errors to BLK_STS statuses, so that -ENOSPC, which indicates virtqueue full is still mapped to BLK_STS_DEV_RESOURCE, but -ENOMEM which indicates non-device specific resource outage is mapped to BLK_STS_RESOURCE. Signed-off-by: Halil Pasic <pasic at linux.ibm.com> Link: https://lore.kernel.org/r/20200213123728.61216-3-pasic at linux.ibm.com Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Review...

From: Halil Pasic <pasic at linux.ibm.com> [ Upstream commit 3d973b2e9a625996ee997c7303cd793b9d197c65 ] Let's change the mapping between virtqueue_add errors to BLK_STS statuses, so that -ENOSPC, which indicates virtqueue full is still mapped to BLK_STS_DEV_RESOURCE, but -ENOMEM which indicates non-device specific resource outage is mapped to BLK_STS_RESOURCE. Signed-off-by: Halil Pasic <pasic at linux.ibm.com> Link: https://lore.kernel.org/r/20200213123728.61216-3-pasic at linux.ibm.com Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Review...

From: Halil Pasic <pasic at linux.ibm.com> [ Upstream commit 3d973b2e9a625996ee997c7303cd793b9d197c65 ] Let's change the mapping between virtqueue_add errors to BLK_STS statuses, so that -ENOSPC, which indicates virtqueue full is still mapped to BLK_STS_DEV_RESOURCE, but -ENOMEM which indicates non-device specific resource outage is mapped to BLK_STS_RESOURCE. Signed-off-by: Halil Pasic <pasic at linux.ibm.com> Link: https://lore.kernel.org/r/20200213123728.61216-3-pasic at linux.ibm.com Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Review...

...gt; + if (err == -ENOSPC) > + blk_mq_stop_hw_queue(hctx); > spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); > - /* Out of mem doesn't actually happen, since we fall back > - * to direct descriptors */ > if (err == -ENOMEM || err == -ENOSPC) > return BLK_STS_DEV_RESOURCE; > return BLK_STS_IOERR; >

...Notes ===== * When out of descriptors (which might regarded as a similar out of resources condition) virtio uses -ENOSPC, this however seems wrong, as ENOSPC is defined as -ENOSPC. Thus I choose -ENOMEM over -ENOSPC. * In virtio_queue_rq() in virtio_blk.c both -ENOMEM and -ENOSPC are handled as BLK_STS_DEV_RESOURCE. Returning BLK_STS_RESOURCE however seems more appropriate for dma mapping failed as we are talking about a global, and not a device local resource. Both seem to do the trick. * Mimu tested the patch with virtio-blk and virtio-net (thanks!). We should look into how other virtio devices behave when...

...to global resource outage. + */ + if (err == -ENOSPC) + blk_mq_stop_hw_queue(hctx); spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); - /* Out of mem doesn't actually happen, since we fall back - * to direct descriptors */ if (err == -ENOMEM || err == -ENOSPC) return BLK_STS_DEV_RESOURCE; return BLK_STS_IOERR; -- 2.17.1