[PATCH kernel-4.19 0/2] virtio_blk: add discard and write zeroes support
virtio_blk: add discard and write zeroes support, mainly for guest os xuliqun (2): virtio_blk: add discard and write zeroes support virtio_blk: fix handling single range discard request drivers/block/virtio_blk.c | 98 ++++++++++++++++++++++++++++++++++++++++- include/uapi/linux/virtio_blk.h | 54 +++++++++++++++++++++++ 2 files changed, 150 insertions(+), 2 deletions(-) -- 2.16.2
mainline inclusion from mainline-5.14-rc7 commit 1f23816b8eb8fdc39990abe166c10a18c16f6b21 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I47ITN CVE: NA ------------------------------------------------- In commit 88c85538, "virtio-blk: add discard and write zeroes features to specification" (https://github.com/oasis-tcs/virtio-spec), the virtio block specification has been extended to add VIRTIO_BLK_T_DISCARD and VIRTIO_BLK_T_WRITE_ZEROES commands. This patch enables support for discard and write zeroes in the virtio-blk driver when the device advertises the corresponding features, VIRTIO_BLK_F_DISCARD and VIRTIO_BLK_F_WRITE_ZEROES. Signed-off-by: Changpeng Liu <changpeng.liu@intel.com> Signed-off-by: Daniel Verkamp <dverkamp@chromium.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: xuliqun <xuliqun@huayun.com> --- drivers/block/virtio_blk.c | 83 ++++++++++++++++++++++++++++++++++++++++- include/uapi/linux/virtio_blk.h | 54 +++++++++++++++++++++++++++ 2 files changed, 135 insertions(+), 2 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index c7b92a9902a5..74c17692acf9 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -18,6 +18,7 @@ #define PART_BITS 4 #define VQ_NAME_LEN 16 +#define MAX_DISCARD_SEGMENTS 256u static int major; static DEFINE_IDA(vd_index_ida); @@ -188,10 +189,48 @@ static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr, return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC); } +static int virtblk_setup_discard_write_zeroes(struct request *req, bool unmap) +{ + unsigned short segments = blk_rq_nr_discard_segments(req); + unsigned short n = 0; + struct virtio_blk_discard_write_zeroes *range; + struct bio *bio; + u32 flags = 0; + + if (unmap) + flags |= VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP; + + range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC); + if (!range) + return -ENOMEM; + + __rq_for_each_bio(bio, req) { + u64 sector = bio->bi_iter.bi_sector; + u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT; + + range[n].flags = cpu_to_le32(flags); + range[n].num_sectors = cpu_to_le32(num_sectors); + range[n].sector = cpu_to_le64(sector); + n++; + } + + req->special_vec.bv_page = virt_to_page(range); + req->special_vec.bv_offset = offset_in_page(range); + req->special_vec.bv_len = sizeof(*range) * segments; + req->rq_flags |= RQF_SPECIAL_PAYLOAD; + + return 0; +} + static inline void virtblk_request_done(struct request *req) { struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); + if (req->rq_flags & RQF_SPECIAL_PAYLOAD) { + kfree(page_address(req->special_vec.bv_page) + + req->special_vec.bv_offset); + } + switch (req_op(req)) { case REQ_OP_SCSI_IN: case REQ_OP_SCSI_OUT: @@ -241,6 +280,7 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, int qid = hctx->queue_num; int err; bool notify = false; + bool unmap = false; u32 type; BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); @@ -253,6 +293,13 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, case REQ_OP_FLUSH: type = VIRTIO_BLK_T_FLUSH; break; + case REQ_OP_DISCARD: + type = VIRTIO_BLK_T_DISCARD; + break; + case REQ_OP_WRITE_ZEROES: + type = VIRTIO_BLK_T_WRITE_ZEROES; + unmap = !(req->cmd_flags & REQ_NOUNMAP); + break; case REQ_OP_SCSI_IN: case REQ_OP_SCSI_OUT: type = VIRTIO_BLK_T_SCSI_CMD; @@ -272,6 +319,12 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, blk_mq_start_request(req); + if (type == VIRTIO_BLK_T_DISCARD || type == VIRTIO_BLK_T_WRITE_ZEROES) { + err = virtblk_setup_discard_write_zeroes(req, unmap); + if (err) + return BLK_STS_RESOURCE; + } + num = blk_rq_map_sg(hctx->queue, req, vbr->sg); if (num) { if (rq_data_dir(req) == WRITE) @@ -904,6 +957,32 @@ static int virtblk_probe(struct virtio_device *vdev) if (!err && opt_io_size) blk_queue_io_opt(q, blk_size * opt_io_size); + if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) { + q->limits.discard_granularity = blk_size; + + virtio_cread(vdev, struct virtio_blk_config, + discard_sector_alignment, &v); + q->limits.discard_alignment = v ? v << SECTOR_SHIFT : 0; + + virtio_cread(vdev, struct virtio_blk_config, + max_discard_sectors, &v); + blk_queue_max_discard_sectors(q, v ? v : UINT_MAX); + + virtio_cread(vdev, struct virtio_blk_config, max_discard_seg, + &v); + blk_queue_max_discard_segments(q, + min_not_zero(v, + MAX_DISCARD_SEGMENTS)); + + blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); + } + + if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) { + virtio_cread(vdev, struct virtio_blk_config, + max_write_zeroes_sectors, &v); + blk_queue_max_write_zeroes_sectors(q, v ? v : UINT_MAX); + } + virtblk_update_capacity(vblk, false); virtio_device_ready(vdev); @@ -1003,14 +1082,14 @@ static unsigned int features_legacy[] = { VIRTIO_BLK_F_SCSI, #endif VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, - VIRTIO_BLK_F_MQ, + VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES, } ; static unsigned int features[] = { VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, - VIRTIO_BLK_F_MQ, + VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES, }; static struct virtio_driver virtio_blk = { diff --git a/include/uapi/linux/virtio_blk.h b/include/uapi/linux/virtio_blk.h index 9ebe4d968dd5..0f99d7b49ede 100644 --- a/include/uapi/linux/virtio_blk.h +++ b/include/uapi/linux/virtio_blk.h @@ -38,6 +38,8 @@ #define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/ #define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */ #define VIRTIO_BLK_F_MQ 12 /* support more than one vq */ +#define VIRTIO_BLK_F_DISCARD 13 /* DISCARD is supported */ +#define VIRTIO_BLK_F_WRITE_ZEROES 14 /* WRITE ZEROES is supported */ /* Legacy feature bits */ #ifndef VIRTIO_BLK_NO_LEGACY @@ -86,6 +88,39 @@ struct virtio_blk_config { /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */ __u16 num_queues; + + /* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */ + /* + * The maximum discard sectors (in 512-byte sectors) for + * one segment. + */ + __u32 max_discard_sectors; + /* + * The maximum number of discard segments in a + * discard command. + */ + __u32 max_discard_seg; + /* Discard commands must be aligned to this number of sectors. */ + __u32 discard_sector_alignment; + + /* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */ + /* + * The maximum number of write zeroes sectors (in 512-byte sectors) in + * one segment. + */ + __u32 max_write_zeroes_sectors; + /* + * The maximum number of segments in a write zeroes + * command. + */ + __u32 max_write_zeroes_seg; + /* + * Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the + * deallocation of one or more of the sectors. + */ + __u8 write_zeroes_may_unmap; + + __u8 unused1[3]; } __attribute__((packed)); /* @@ -114,6 +149,12 @@ struct virtio_blk_config { /* Get device ID command */ #define VIRTIO_BLK_T_GET_ID 8 +/* Discard command */ +#define VIRTIO_BLK_T_DISCARD 11 + +/* Write zeroes command */ +#define VIRTIO_BLK_T_WRITE_ZEROES 13 + #ifndef VIRTIO_BLK_NO_LEGACY /* Barrier before this op. */ #define VIRTIO_BLK_T_BARRIER 0x80000000 @@ -133,6 +174,19 @@ struct virtio_blk_outhdr { __virtio64 sector; }; +/* Unmap this range (only valid for write zeroes command) */ +#define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP 0x00000001 + +/* Discard/write zeroes range for each request. */ +struct virtio_blk_discard_write_zeroes { + /* discard/write zeroes start sector */ + __le64 sector; + /* number of discard/write zeroes sectors */ + __le32 num_sectors; + /* flags for this range */ + __le32 flags; +}; + #ifndef VIRTIO_BLK_NO_LEGACY struct virtio_scsi_inhdr { __virtio32 errors; -- 2.16.2
mainline inclusion from mainline-5.14-rc7 commit af822aa68fbdf0a480a17462ed70232998127453 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I47ITN CVE: NA ------------------------------------------------- 1f23816 ("virtio_blk: add discard and write zeroes support") starts to support multi-range discard for virtio-blk. However, the virtio-blk disk may report max discard segment as 1, at least that is exactly what qemu is doing. So far, block layer switches to normal request merge if max discard segment limit is 1, and multiple bios can be merged to single segment. This way may cause memory corruption in virtblk_setup_discard_write_zeroes(). Fix the issue by handling single max discard segment in straightforward way. Fixes: 1f23816 ("virtio_blk: add discard and write zeroes support") Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Changpeng Liu <changpeng.liu@intel.com> Cc: Daniel Verkamp <dverkamp@chromium.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: xuliqun <xuliqun@huayun.com> --- drivers/block/virtio_blk.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 74c17692acf9..da4f2b744904 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -204,16 +204,31 @@ static int virtblk_setup_discard_write_zeroes(struct request *req, bool unmap) if (!range) return -ENOMEM; - __rq_for_each_bio(bio, req) { - u64 sector = bio->bi_iter.bi_sector; - u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT; - - range[n].flags = cpu_to_le32(flags); - range[n].num_sectors = cpu_to_le32(num_sectors); - range[n].sector = cpu_to_le64(sector); - n++; + /* + * Single max discard segment means multi-range discard isn't + * supported, and block layer only runs contiguity merge like + * normal RW request. So we can't reply on bio for retrieving + * each range info. + */ + if (queue_max_discard_segments(req->q) == 1) { + range[0].flags = cpu_to_le32(flags); + range[0].num_sectors = cpu_to_le32(blk_rq_sectors(req)); + range[0].sector = cpu_to_le64(blk_rq_pos(req)); + n = 1; + } else { + __rq_for_each_bio(bio, req) { + u64 sector = bio->bi_iter.bi_sector; + u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT; + + range[n].flags = cpu_to_le32(flags); + range[n].num_sectors = cpu_to_le32(num_sectors); + range[n].sector = cpu_to_le64(sector); + n++; + } } + WARN_ON_ONCE(n != segments); + req->special_vec.bv_page = virt_to_page(range); req->special_vec.bv_offset = offset_in_page(range); req->special_vec.bv_len = sizeof(*range) * segments; -- 2.16.2
Hi, 徐力群 <xuliqun@huayun.com>，您好 首先非常感谢您参与 openEuler kernel 开发。 On 2021/8/31 22:25, xuliqun wrote:
virtio_blk: add discard and write zeroes support, mainly for guest os
xuliqun (2): virtio_blk: add discard and write zeroes support virtio_blk: fix handling single range discard request
drivers/block/virtio_blk.c | 98 ++++++++++++++++++++++++++++++++++++++++- include/uapi/linux/virtio_blk.h | 54 +++++++++++++++++++++++ 2 files changed, 150 insertions(+), 2 deletions(-)
您的 PATCH 已经合入 openEuler-20.03 LTS，对应 commit 号如下： kernel-4.19 分支 9ada28659187 virtio_blk: fix handling single range discard request 4e5d395f7775 virtio_blk: add discard and write zeroes support openEuler-1.0-LTS 分支 ff7d1fc39476 virtio_blk: fix handling single range discard request b3f8fce99b4a virtio_blk: add discard and write zeroes support 该问题对应 issue https://gitee.com/openeuler/kernel/issues/I47ITN 如果您有什么信息要同步的，可以在 issue 里面更新, 或者联系 @成坚(gatieme) 最后 再次感谢您参与 openEuler，社区有您更精彩。 ---- 成坚
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