NVMe: Merge the nvme_bio and nvme_prp data structures

The new merged data structure is called nvme_iod.  This improves performance
for mid-sized I/Os (in the 16k range) since we save a memory allocation.
It is also a slightly simpler interface to use.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
This commit is contained in:
Matthew Wilcox 2011-12-20 13:34:52 -05:00
parent 5c1281a3bf
commit eca18b2394

View File

@ -290,52 +290,70 @@ static int nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
return 0;
}
struct nvme_prps {
int npages; /* 0 means small pool in use */
/*
* The nvme_iod describes the data in an I/O, including the list of PRP
* entries. You can't see it in this data structure because C doesn't let
* me express that. Use nvme_alloc_iod to ensure there's enough space
* allocated to store the PRP list.
*/
struct nvme_iod {
void *private; /* For the use of the submitter of the I/O */
int npages; /* In the PRP list. 0 means small pool in use */
int offset; /* Of PRP list */
int nents; /* Used in scatterlist */
int length; /* Of data, in bytes */
dma_addr_t first_dma;
__le64 *list[0];
struct scatterlist sg[0];
};
static void nvme_free_prps(struct nvme_dev *dev, struct nvme_prps *prps)
static __le64 **iod_list(struct nvme_iod *iod)
{
return ((void *)iod) + iod->offset;
}
/*
* Will slightly overestimate the number of pages needed. This is OK
* as it only leads to a small amount of wasted memory for the lifetime of
* the I/O.
*/
static int nvme_npages(unsigned size)
{
unsigned nprps = DIV_ROUND_UP(size + PAGE_SIZE, PAGE_SIZE);
return DIV_ROUND_UP(8 * nprps, PAGE_SIZE - 8);
}
static struct nvme_iod *
nvme_alloc_iod(unsigned nseg, unsigned nbytes, gfp_t gfp)
{
struct nvme_iod *iod = kmalloc(sizeof(struct nvme_iod) +
sizeof(__le64 *) * nvme_npages(nbytes) +
sizeof(struct scatterlist) * nseg, gfp);
if (iod) {
iod->offset = offsetof(struct nvme_iod, sg[nseg]);
iod->npages = -1;
iod->length = nbytes;
}
return iod;
}
static void nvme_free_iod(struct nvme_dev *dev, struct nvme_iod *iod)
{
const int last_prp = PAGE_SIZE / 8 - 1;
int i;
dma_addr_t prp_dma;
__le64 **list = iod_list(iod);
dma_addr_t prp_dma = iod->first_dma;
if (!prps)
return;
prp_dma = prps->first_dma;
if (prps->npages == 0)
dma_pool_free(dev->prp_small_pool, prps->list[0], prp_dma);
for (i = 0; i < prps->npages; i++) {
__le64 *prp_list = prps->list[i];
if (iod->npages == 0)
dma_pool_free(dev->prp_small_pool, list[0], prp_dma);
for (i = 0; i < iod->npages; i++) {
__le64 *prp_list = list[i];
dma_addr_t next_prp_dma = le64_to_cpu(prp_list[last_prp]);
dma_pool_free(dev->prp_page_pool, prp_list, prp_dma);
prp_dma = next_prp_dma;
}
kfree(prps);
}
struct nvme_bio {
struct bio *bio;
int nents;
struct nvme_prps *prps;
struct scatterlist sg[0];
};
/* XXX: use a mempool */
static struct nvme_bio *alloc_nbio(unsigned nseg, gfp_t gfp)
{
return kzalloc(sizeof(struct nvme_bio) +
sizeof(struct scatterlist) * nseg, gfp);
}
static void free_nbio(struct nvme_dev *dev, struct nvme_bio *nbio)
{
nvme_free_prps(dev, nbio->prps);
kfree(nbio);
kfree(iod);
}
static void requeue_bio(struct nvme_dev *dev, struct bio *bio)
@ -351,13 +369,13 @@ static void requeue_bio(struct nvme_dev *dev, struct bio *bio)
static void bio_completion(struct nvme_dev *dev, void *ctx,
struct nvme_completion *cqe)
{
struct nvme_bio *nbio = ctx;
struct bio *bio = nbio->bio;
struct nvme_iod *iod = ctx;
struct bio *bio = iod->private;
u16 status = le16_to_cpup(&cqe->status) >> 1;
dma_unmap_sg(&dev->pci_dev->dev, nbio->sg, nbio->nents,
dma_unmap_sg(&dev->pci_dev->dev, iod->sg, iod->nents,
bio_data_dir(bio) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
free_nbio(dev, nbio);
nvme_free_iod(dev, iod);
if (status) {
bio_endio(bio, -EIO);
} else if (bio->bi_vcnt > bio->bi_idx) {
@ -368,25 +386,25 @@ static void bio_completion(struct nvme_dev *dev, void *ctx,
}
/* length is in bytes. gfp flags indicates whether we may sleep. */
static struct nvme_prps *nvme_setup_prps(struct nvme_dev *dev,
struct nvme_common_command *cmd,
struct scatterlist *sg, int *len,
gfp_t gfp)
static int nvme_setup_prps(struct nvme_dev *dev,
struct nvme_common_command *cmd, struct nvme_iod *iod,
int total_len, gfp_t gfp)
{
struct dma_pool *pool;
int length = *len;
int length = total_len;
struct scatterlist *sg = iod->sg;
int dma_len = sg_dma_len(sg);
u64 dma_addr = sg_dma_address(sg);
int offset = offset_in_page(dma_addr);
__le64 *prp_list;
__le64 **list = iod_list(iod);
dma_addr_t prp_dma;
int nprps, npages, i;
struct nvme_prps *prps = NULL;
int nprps, i;
cmd->prp1 = cpu_to_le64(dma_addr);
length -= (PAGE_SIZE - offset);
if (length <= 0)
return prps;
return total_len;
dma_len -= (PAGE_SIZE - offset);
if (dma_len) {
@ -399,46 +417,35 @@ static struct nvme_prps *nvme_setup_prps(struct nvme_dev *dev,
if (length <= PAGE_SIZE) {
cmd->prp2 = cpu_to_le64(dma_addr);
return prps;
return total_len;
}
nprps = DIV_ROUND_UP(length, PAGE_SIZE);
npages = DIV_ROUND_UP(8 * nprps, PAGE_SIZE - 8);
prps = kmalloc(sizeof(*prps) + sizeof(__le64 *) * npages, gfp);
if (!prps) {
cmd->prp2 = cpu_to_le64(dma_addr);
*len = (*len - length) + PAGE_SIZE;
return prps;
}
if (nprps <= (256 / 8)) {
pool = dev->prp_small_pool;
prps->npages = 0;
iod->npages = 0;
} else {
pool = dev->prp_page_pool;
prps->npages = 1;
iod->npages = 1;
}
prp_list = dma_pool_alloc(pool, gfp, &prp_dma);
if (!prp_list) {
cmd->prp2 = cpu_to_le64(dma_addr);
*len = (*len - length) + PAGE_SIZE;
kfree(prps);
return NULL;
iod->npages = -1;
return (total_len - length) + PAGE_SIZE;
}
prps->list[0] = prp_list;
prps->first_dma = prp_dma;
list[0] = prp_list;
iod->first_dma = prp_dma;
cmd->prp2 = cpu_to_le64(prp_dma);
i = 0;
for (;;) {
if (i == PAGE_SIZE / 8) {
__le64 *old_prp_list = prp_list;
prp_list = dma_pool_alloc(pool, gfp, &prp_dma);
if (!prp_list) {
*len = (*len - length);
return prps;
}
prps->list[prps->npages++] = prp_list;
if (!prp_list)
return total_len - length;
list[iod->npages++] = prp_list;
prp_list[0] = old_prp_list[i - 1];
old_prp_list[i - 1] = cpu_to_le64(prp_dma);
i = 1;
@ -457,21 +464,21 @@ static struct nvme_prps *nvme_setup_prps(struct nvme_dev *dev,
dma_len = sg_dma_len(sg);
}
return prps;
return total_len;
}
/* 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,
static int nvme_map_bio(struct device *dev, struct nvme_iod *iod,
struct bio *bio, enum dma_data_direction dma_dir, int psegs)
{
struct bio_vec *bvec, *bvprv = NULL;
struct scatterlist *sg = NULL;
int i, old_idx, length = 0, nsegs = 0;
sg_init_table(nbio->sg, psegs);
sg_init_table(iod->sg, psegs);
old_idx = bio->bi_idx;
bio_for_each_segment(bvec, bio, i) {
if (bvprv && BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) {
@ -479,7 +486,7 @@ static int nvme_map_bio(struct device *dev, struct nvme_bio *nbio,
} else {
if (bvprv && BIOVEC_NOT_VIRT_MERGEABLE(bvprv, bvec))
break;
sg = sg ? sg + 1 : nbio->sg;
sg = sg ? sg + 1 : iod->sg;
sg_set_page(sg, bvec->bv_page, bvec->bv_len,
bvec->bv_offset);
nsegs++;
@ -488,9 +495,9 @@ static int nvme_map_bio(struct device *dev, struct nvme_bio *nbio,
bvprv = bvec;
}
bio->bi_idx = i;
nbio->nents = nsegs;
iod->nents = nsegs;
sg_mark_end(sg);
if (dma_map_sg(dev, nbio->sg, nbio->nents, dma_dir) == 0) {
if (dma_map_sg(dev, iod->sg, iod->nents, dma_dir) == 0) {
bio->bi_idx = old_idx;
return -ENOMEM;
}
@ -531,7 +538,7 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
struct bio *bio)
{
struct nvme_command *cmnd;
struct nvme_bio *nbio;
struct nvme_iod *iod;
enum dma_data_direction dma_dir;
int cmdid, length, result = -ENOMEM;
u16 control;
@ -544,15 +551,15 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
return result;
}
nbio = alloc_nbio(psegs, GFP_ATOMIC);
if (!nbio)
iod = nvme_alloc_iod(psegs, bio->bi_size, GFP_ATOMIC);
if (!iod)
goto nomem;
nbio->bio = bio;
iod->private = bio;
result = -EBUSY;
cmdid = alloc_cmdid(nvmeq, nbio, bio_completion, IO_TIMEOUT);
cmdid = alloc_cmdid(nvmeq, iod, bio_completion, IO_TIMEOUT);
if (unlikely(cmdid < 0))
goto free_nbio;
goto free_iod;
if ((bio->bi_rw & REQ_FLUSH) && !psegs)
return nvme_submit_flush(nvmeq, ns, cmdid);
@ -578,15 +585,15 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
dma_dir = DMA_FROM_DEVICE;
}
result = nvme_map_bio(nvmeq->q_dmadev, nbio, bio, dma_dir, psegs);
result = nvme_map_bio(nvmeq->q_dmadev, iod, bio, dma_dir, psegs);
if (result < 0)
goto free_nbio;
goto free_iod;
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,
&length, GFP_ATOMIC);
length = nvme_setup_prps(nvmeq->dev, &cmnd->common, iod, length,
GFP_ATOMIC);
cmnd->rw.slba = cpu_to_le64(bio->bi_sector >> (ns->lba_shift - 9));
cmnd->rw.length = cpu_to_le16((length >> ns->lba_shift) - 1);
cmnd->rw.control = cpu_to_le16(control);
@ -600,8 +607,8 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
return 0;
free_nbio:
free_nbio(nvmeq->dev, nbio);
free_iod:
nvme_free_iod(nvmeq->dev, iod);
nomem:
return result;
}
@ -1005,18 +1012,18 @@ static int __devinit nvme_configure_admin_queue(struct nvme_dev *dev)
return result;
}
static int nvme_map_user_pages(struct nvme_dev *dev, int write,
unsigned long addr, unsigned length,
struct scatterlist **sgp)
static struct nvme_iod *nvme_map_user_pages(struct nvme_dev *dev, int write,
unsigned long addr, unsigned length)
{
int i, err, count, nents, offset;
struct scatterlist *sg;
struct page **pages;
struct nvme_iod *iod;
if (addr & 3)
return -EINVAL;
return ERR_PTR(-EINVAL);
if (!length)
return -EINVAL;
return ERR_PTR(-EINVAL);
offset = offset_in_page(addr);
count = DIV_ROUND_UP(offset + length, PAGE_SIZE);
@ -1029,7 +1036,8 @@ static int nvme_map_user_pages(struct nvme_dev *dev, int write,
goto put_pages;
}
sg = kcalloc(count, sizeof(*sg), GFP_KERNEL);
iod = nvme_alloc_iod(count, length, GFP_KERNEL);
sg = iod->sg;
sg_init_table(sg, count);
for (i = 0; i < count; i++) {
sg_set_page(&sg[i], pages[i],
@ -1042,22 +1050,24 @@ static int nvme_map_user_pages(struct nvme_dev *dev, int write,
nents = dma_map_sg(&dev->pci_dev->dev, sg, count,
write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
if (!nents)
goto put_pages;
goto free_iod;
kfree(pages);
*sgp = sg;
return nents;
return iod;
free_iod:
kfree(iod);
put_pages:
for (i = 0; i < count; i++)
put_page(pages[i]);
kfree(pages);
return err;
return ERR_PTR(err);
}
static void nvme_unmap_user_pages(struct nvme_dev *dev, int write,
unsigned long addr, int length, struct scatterlist *sg)
unsigned long addr, int length, struct nvme_iod *iod)
{
struct scatterlist *sg = iod->sg;
int i, count;
count = DIV_ROUND_UP(offset_in_page(addr) + length, PAGE_SIZE);
@ -1074,9 +1084,8 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
struct nvme_user_io io;
struct nvme_command c;
unsigned length;
int nents, status;
struct scatterlist *sg;
struct nvme_prps *prps;
int status;
struct nvme_iod *iod;
if (copy_from_user(&io, uio, sizeof(io)))
return -EFAULT;
@ -1086,15 +1095,14 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
case nvme_cmd_write:
case nvme_cmd_read:
case nvme_cmd_compare:
nents = nvme_map_user_pages(dev, io.opcode & 1, io.addr,
length, &sg);
iod = nvme_map_user_pages(dev, io.opcode & 1, io.addr, length);
break;
default:
return -EINVAL;
}
if (nents < 0)
return nents;
if (IS_ERR(iod))
return PTR_ERR(iod);
memset(&c, 0, sizeof(c));
c.rw.opcode = io.opcode;
@ -1108,7 +1116,7 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
c.rw.apptag = io.apptag;
c.rw.appmask = io.appmask;
/* XXX: metadata */
prps = nvme_setup_prps(dev, &c.common, sg, &length, GFP_KERNEL);
length = nvme_setup_prps(dev, &c.common, iod, length, GFP_KERNEL);
nvmeq = get_nvmeq(dev);
/*
@ -1123,8 +1131,8 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
else
status = nvme_submit_sync_cmd(nvmeq, &c, NULL, IO_TIMEOUT);
nvme_unmap_user_pages(dev, io.opcode & 1, io.addr, length, sg);
nvme_free_prps(dev, prps);
nvme_unmap_user_pages(dev, io.opcode & 1, io.addr, length, iod);
nvme_free_iod(dev, iod);
return status;
}
@ -1134,9 +1142,8 @@ static int nvme_user_admin_cmd(struct nvme_ns *ns,
struct nvme_dev *dev = ns->dev;
struct nvme_admin_cmd cmd;
struct nvme_command c;
int status, length, nents = 0;
struct scatterlist *sg;
struct nvme_prps *prps = NULL;
int status, length;
struct nvme_iod *iod;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
@ -1158,19 +1165,21 @@ static int nvme_user_admin_cmd(struct nvme_ns *ns,
length = cmd.data_len;
if (cmd.data_len) {
nents = nvme_map_user_pages(dev, 1, cmd.addr, length, &sg);
if (nents < 0)
return nents;
prps = nvme_setup_prps(dev, &c.common, sg, &length, GFP_KERNEL);
iod = nvme_map_user_pages(dev, 1, cmd.addr, length);
if (IS_ERR(iod))
return PTR_ERR(iod);
length = nvme_setup_prps(dev, &c.common, iod, length,
GFP_KERNEL);
}
if (length != cmd.data_len)
status = -ENOMEM;
else
status = nvme_submit_admin_cmd(dev, &c, NULL);
if (cmd.data_len) {
nvme_unmap_user_pages(dev, 0, cmd.addr, cmd.data_len, sg);
nvme_free_prps(dev, prps);
nvme_unmap_user_pages(dev, 0, cmd.addr, cmd.data_len, iod);
nvme_free_iod(dev, iod);
}
return status;
}