kernel/linux.git/drivers/block/virtio_blk.c, branch v6.6.131

virtio-blk: don't keep queue frozen during system suspend

2025-01-02T09:32:06+00:00

[ Upstream commit 7678abee0867e6b7fb89aa40f6e9f575f755fb37 ] Commit 4ce6e2db00de ("virtio-blk: Ensure no requests in virtqueues before deleting vqs.") replaces queue quiesce with queue freeze in virtio-blk's PM callbacks. And the motivation is to drain inflight IOs before suspending. block layer's queue freeze looks very handy, but it is also easy to cause deadlock, such as, any attempt to call into bio_queue_enter() may run into deadlock if the queue is frozen in current context. There are all kinds of ->suspend() called in suspend context, so keeping queue frozen in the whole suspend context isn't one good idea. And Marek reported lockdep warning[1] caused by virtio-blk's freeze queue in virtblk_freeze(). [1] https://lore.kernel.org/linux-block/ca16370e-d646-4eee-b9cc-87277c89c43c@samsung.com/ Given the motivation is to drain in-flight IOs, it can be done by calling freeze & unfreeze, meantime restore to previous behavior by keeping queue quiesced during suspend. Cc: Yi Sun Cc: Michael S. Tsirkin Cc: Jason Wang Cc: Stefan Hajnoczi Cc: virtualization@lists.linux.dev Reported-by: Marek Szyprowski Signed-off-by: Ming Lei Acked-by: Stefan Hajnoczi Link: https://lore.kernel.org/r/20241112125821.1475793-1-ming.lei@redhat.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

virtio_blk: reverse request order in virtio_queue_rqs

2024-12-09T09:31:46+00:00

[ Upstream commit 7f212e997edbb7a2cb85cef2ac14265dfaf88717 ] blk_mq_flush_plug_list submits requests in the reverse order that they were submitted, which leads to a rather suboptimal I/O pattern especially in rotational devices. Fix this by rewriting virtio_queue_rqs so that it always pops the requests from the passed in request list, and then adds them to the head of a local submit list. This actually simplifies the code a bit as it removes the complicated list splicing, at the cost of extra updates of the rq_next pointer. As that should be cache hot anyway it should be an easy price to pay. Fixes: 0e9911fa768f ("virtio-blk: support mq_ops->queue_rqs()") Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20241113152050.157179-3-hch@lst.de Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

virtio-blk: Ensure no requests in virtqueues before deleting vqs.

2024-03-01T12:34:56+00:00

[ Upstream commit 4ce6e2db00de8103a0687fb0f65fd17124a51aaa ] Ensure no remaining requests in virtqueues before resetting vdev and deleting virtqueues. Otherwise these requests will never be completed. It may cause the system to become unresponsive. Function blk_mq_quiesce_queue() can ensure that requests have become in_flight status, but it cannot guarantee that requests have been processed by the device. Virtqueues should never be deleted before all requests become complete status. Function blk_mq_freeze_queue() ensure that all requests in virtqueues become complete status. And no requests can enter in virtqueues. Signed-off-by: Yi Sun Reviewed-by: Stefan Hajnoczi Link: https://lore.kernel.org/r/20240129085250.1550594-1-yi.sun@unisoc.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

virtio_blk: fix snprintf truncation compiler warning

2024-01-20T10:51:46+00:00

[ Upstream commit b8e0792449928943c15d1af9f63816911d139267 ] Commit 4e0400525691 ("virtio-blk: support polling I/O") triggers the following gcc 13 W=1 warnings: drivers/block/virtio_blk.c: In function ‘init_vq’: drivers/block/virtio_blk.c:1077:68: warning: ‘%d’ directive output may be truncated writing between 1 and 11 bytes into a region of size 7 [-Wformat-truncation=] 1077 | snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i); | ^~ drivers/block/virtio_blk.c:1077:58: note: directive argument in the range [-2147483648, 65534] 1077 | snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i); | ^~~~~~~~~~~~~ drivers/block/virtio_blk.c:1077:17: note: ‘snprintf’ output between 11 and 21 bytes into a destination of size 16 1077 | snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%d", i); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This is a false positive because the lower bound -2147483648 is incorrect. The true range of i is [0, num_vqs - 1] where 0 < num_vqs < 65536. The code mixes int, unsigned short, and unsigned int types in addition to using "%d" for an unsigned value. Use unsigned short and "%u" consistently to solve the compiler warning. Cc: Suwan Kim Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202312041509.DIyvEt9h-lkp@intel.com/ Signed-off-by: Stefan Hajnoczi Message-Id: <20231204140743.1487843-1-stefanha@redhat.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

virtio-blk: fix implicit overflow on virtio_max_dma_size

2023-11-28T17:19:46+00:00

[ Upstream commit fafb51a67fb883eb2dde352539df939a251851be ] The following codes have an implicit conversion from size_t to u32: (u32)max_size = (size_t)virtio_max_dma_size(vdev); This may lead overflow, Ex (size_t)4G -> (u32)0. Once virtio_max_dma_size() has a larger size than U32_MAX, use U32_MAX instead. Signed-off-by: zhenwei pi Message-Id: <20230904061045.510460-1-pizhenwei@bytedance.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

Merge branch '6.5/scsi-staging' into 6.5/scsi-fixes

2023-07-11T16:15:15+00:00

Pull in the currently staged SCSI fixes for 6.5. Signed-off-by: Martin K. Petersen

scsi: block: virtio_blk: Set zone limits before revalidating zones

2023-07-06T01:58:10+00:00

In virtblk_probe_zoned_device(), execute blk_queue_chunk_sectors() and blk_queue_max_zone_append_sectors() to respectively set the zoned device zone size and maximum zone append sector limit before executing blk_revalidate_disk_zones(). This is to allow the block layer zone reavlidation to check these device characteristics prior to checking all zones of the device. Signed-off-by: Damien Le Moal Link: https://lore.kernel.org/r/20230703024812.76778-5-dlemoal@kernel.org Reviewed-by: Bart Van Assche Reviewed-by: Dmitry Fomichev Reviewed-by: Johannes Thumshirn Signed-off-by: Martin K. Petersen

Revert "virtio-blk: support completion batching for the IRQ path"

2023-06-21T08:14:28+00:00

This reverts commit 07b679f70d73483930e8d3c293942416d9cd5c13. This change appears to have broken things... We now see applications hanging during disk accesses. e.g. multi-port virtio-blk device running in h/w (FPGA) Host running a simple 'fio' test. [global] thread=1 direct=1 ioengine=libaio norandommap=1 group_reporting=1 bs=4K rw=read iodepth=128 runtime=1 numjobs=4 time_based [job0] filename=/dev/vda [job1] filename=/dev/vdb [job2] filename=/dev/vdc ... [job15] filename=/dev/vdp i.e. 16 disks; 4 queues per disk; simple burst of 4KB reads This is repeatedly run in a loop. After a few, normally <10 seconds, fio hangs. With 64 queues (16 disks), failure occurs within a few seconds; with 8 queues (2 disks) it may take ~hour before hanging. Last message: fio-3.19 Starting 8 threads Jobs: 1 (f=1): [_(7),R(1)][68.3%][eta 03h:11m:06s] I think this means at the end of the run 1 queue was left incomplete. 'diskstats' (run while fio is hung) shows no outstanding transactions. e.g. $ cat /proc/diskstats ... 252 0 vda 1843140071 0 14745120568 712568645 0 0 0 0 0 3117947 712568645 0 0 0 0 0 0 252 16 vdb 1816291511 0 14530332088 704905623 0 0 0 0 0 3117711 704905623 0 0 0 0 0 0 ... Other stats (in the h/w, and added to the virtio-blk driver ([a]virtio_queue_rq(), [b]virtblk_handle_req(), [c]virtblk_request_done()) all agree, and show every request had a completion, and that virtblk_request_done() never gets called. e.g. PF= 0 vq=0 1 2 3 [a]request_count - 839416590 813148916 105586179 84988123 [b]completion1_count - 839416590 813148916 105586179 84988123 [c]completion2_count - 0 0 0 0 PF= 1 vq=0 1 2 3 [a]request_count - 823335887 812516140 104582672 75856549 [b]completion1_count - 823335887 812516140 104582672 75856549 [c]completion2_count - 0 0 0 0 i.e. the issue is after the virtio-blk driver. This change was introduced in kernel 6.3.0. I am seeing this using 6.3.3. If I run with an earlier kernel (5.15), it does not occur. If I make a simple patch to the 6.3.3 virtio-blk driver, to skip the blk_mq_add_to_batch()call, it does not fail. e.g. kernel 5.15 - this is OK virtio_blk.c,virtblk_done() [irq handler] if (likely(!blk_should_fake_timeout(req->q))) { blk_mq_complete_request(req); } kernel 6.3.3 - this fails virtio_blk.c,virtblk_handle_req() [irq handler] if (likely(!blk_should_fake_timeout(req->q))) { if (!blk_mq_complete_request_remote(req)) { if (!blk_mq_add_to_batch(req, iob, virtblk_vbr_status(vbr), virtblk_complete_batch)) { virtblk_request_done(req); //this never gets called... so blk_mq_add_to_batch() must always succeed } } } If I do, kernel 6.3.3 - this is OK virtio_blk.c,virtblk_handle_req() [irq handler] if (likely(!blk_should_fake_timeout(req->q))) { if (!blk_mq_complete_request_remote(req)) { virtblk_request_done(req); //force this here... if (!blk_mq_add_to_batch(req, iob, virtblk_vbr_status(vbr), virtblk_complete_batch)) { virtblk_request_done(req); //this never gets called... so blk_mq_add_to_batch() must always succeed } } } Perhaps you might like to fix/test/revert this change... Martin Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202306090826.C1fZmdMe-lkp@intel.com/ Cc: Suwan Kim Tested-by: edliaw@google.com Reported-by: "Roberts, Martin" Message-Id: <336455b4f630f329380a8f53ee8cad3868764d5c.1686295549.git.mst@redhat.com> Signed-off-by: Michael S. Tsirkin

virtio-blk: fix ZBD probe in kernels without ZBD support

2023-04-04T15:01:57+00:00

When the kernel is built without support for zoned block devices, virtio-blk probe needs to error out any host-managed device scans to prevent such devices from appearing in the system as non-zoned. The current virtio-blk code simply bypasses all ZBD checks if CONFIG_BLK_DEV_ZONED is not defined and this leads to host-managed block devices being presented as non-zoned in the OS. This is one of the main problems this patch series is aimed to fix. In this patch, make VIRTIO_BLK_F_ZONED feature defined even when CONFIG_BLK_DEV_ZONED is not. This change makes the code compliant with the voted revision of virtio-blk ZBD spec. Modify the probe code to look at the situation when VIRTIO_BLK_F_ZONED is negotiated in a kernel that is built without ZBD support. In this case, the code checks the zoned model of the device and fails the probe is the device is host-managed. The patch also adds the comment to clarify that the call to perform the zoned device probe is correctly placed after virtio_device ready(). Fixes: 95bfec41bd3d ("virtio-blk: add support for zoned block devices") Cc: stable@vger.kernel.org Signed-off-by: Dmitry Fomichev Reviewed-by: Stefan Hajnoczi Reviewed-by: Damien Le Moal Message-Id: <20230330214953.1088216-3-dmitry.fomichev@wdc.com> Signed-off-by: Michael S. Tsirkin

virtio-blk: fix to match virtio spec

2023-04-04T15:01:57+00:00

The merged patch series to support zoned block devices in virtio-blk is not the most up to date version. The merged patch can be found at https://lore.kernel.org/linux-block/20221016034127.330942-3-dmitry.fomichev@wdc.com/ but the latest and reviewed version is https://lore.kernel.org/linux-block/20221110053952.3378990-3-dmitry.fomichev@wdc.com/ The reason is apparently that the correct mailing lists and maintainers were not copied. The differences between the two are mostly cleanups, but there is one change that is very important in terms of compatibility with the approved virtio-zbd specification. Before it was approved, the OASIS virtio spec had a change in VIRTIO_BLK_T_ZONE_APPEND request layout that is not reflected in the current virtio-blk driver code. In the running code, the status is the first byte of the in-header that is followed by some pad bytes and the u64 that carries the sector at which the data has been written to the zone back to the driver, aka the append sector. This layout turned out to be problematic for implementing in QEMU and the request status byte has been eventually made the last byte of the in-header. The current code doesn't expect that and this causes the append sector value always come as zero to the block layer. This needs to be fixed ASAP. Fixes: 95bfec41bd3d ("virtio-blk: add support for zoned block devices") Cc: stable@vger.kernel.org Signed-off-by: Dmitry Fomichev Reviewed-by: Stefan Hajnoczi Reviewed-by: Damien Le Moal Message-Id: <20230330214953.1088216-2-dmitry.fomichev@wdc.com> Signed-off-by: Michael S. Tsirkin