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NVMe: Handle bios that contain non-virtually contiguous addresses 

NVMe scatterlists must be virtually contiguous, like almost all I/Os.
However, when the filesystem lays out files with a hole, it can be that
adjacent LBAs map to non-adjacent virtual addresses.  Handle this by
submitting one NVMe command at a time for each virtually discontiguous
range.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
This commit is contained in:
Matthew Wilcox 2011-02-23 15:20:00 -05:00
parent 00df5cb4eb
commit 1ad2f8932a
1 changed files with 29 additions and 9 deletions
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38
drivers/block/nvme.c
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@ -315,7 +315,14 @@ static void bio_completion(struct nvme_queue *nvmeq, void *ctx,
dma_unmap_sg(nvmeq->q_dmadev, nbio->sg, nbio->nents,
bio_data_dir(bio) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
free_nbio(nvmeq, nbio);
bio_endio(bio, status ? -EIO : 0);
if (status)
bio_endio(bio, -EIO);
if (bio->bi_vcnt > bio->bi_idx) {
bio_list_add(&nvmeq->sq_cong, bio);
wake_up_process(nvme_thread);
} else {
bio_endio(bio, 0);
}
}
/* length is in bytes */
@ -393,29 +400,41 @@ static struct nvme_prps *nvme_setup_prps(struct nvme_dev *dev,
return prps;
}
/* NVMe scatterlists require no holes in the virtual address */
#define BIOVEC_NOT_VIRT_MERGEABLE(vec1, vec2) ((vec2)->bv_offset || \
(((vec1)->bv_offset + (vec1)->bv_len) % PAGE_SIZE))
static int nvme_map_bio(struct device *dev, struct nvme_bio *nbio,
struct bio *bio, enum dma_data_direction dma_dir, int psegs)
{
struct bio_vec *bvec, *bvprv = NULL;
struct scatterlist *sg = NULL;
int i, nsegs = 0;
int i, old_idx, length = 0, nsegs = 0;
sg_init_table(nbio->sg, psegs);
old_idx = bio->bi_idx;
bio_for_each_segment(bvec, bio, i) {
if (bvprv && BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) {
sg->length += bvec->bv_len;
} else {
/* Check bvprv && offset == 0 */
if (bvprv && BIOVEC_NOT_VIRT_MERGEABLE(bvprv, bvec))
break;
sg = sg ? sg + 1 : nbio->sg;
sg_set_page(sg, bvec->bv_page, bvec->bv_len,
bvec->bv_offset);
nsegs++;
}
length += bvec->bv_len;
bvprv = bvec;
}
bio->bi_idx = i;
nbio->nents = nsegs;
sg_mark_end(sg);
return dma_map_sg(dev, nbio->sg, nbio->nents, dma_dir);
if (dma_map_sg(dev, nbio->sg, nbio->nents, dma_dir) == 0) {
bio->bi_idx = old_idx;
return -ENOMEM;
}
return length;
}
static int nvme_submit_flush(struct nvme_queue *nvmeq, struct nvme_ns *ns,
@ -451,7 +470,7 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
struct nvme_command *cmnd;
struct nvme_bio *nbio;
enum dma_data_direction dma_dir;
int cmdid, result = -ENOMEM;
int cmdid, length, result = -ENOMEM;
u16 control;
u32 dsmgmt;
int psegs = bio_phys_segments(ns->queue, bio);
@ -496,16 +515,17 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
dma_dir = DMA_FROM_DEVICE;
}
result = -ENOMEM;
if (nvme_map_bio(nvmeq->q_dmadev, nbio, bio, dma_dir, psegs) == 0)
result = nvme_map_bio(nvmeq->q_dmadev, nbio, bio, dma_dir, psegs);
if (result < 0)
goto free_nbio;
length = result;
cmnd->rw.command_id = cmdid;
cmnd->rw.nsid = cpu_to_le32(ns->ns_id);
nbio->prps = nvme_setup_prps(nvmeq->dev, &cmnd->common, nbio->sg,
bio->bi_size);
length);
cmnd->rw.slba = cpu_to_le64(bio->bi_sector >> (ns->lba_shift - 9));
cmnd->rw.length = cpu_to_le16((bio->bi_size >> ns->lba_shift) - 1);
cmnd->rw.length = cpu_to_le16((length >> ns->lba_shift) - 1);
cmnd->rw.control = cpu_to_le16(control);
cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);