[PATCH] NVMe: Mismatched host/device page size support
Keith Busch
keith.busch at intel.com
Fri Jun 20 14:27:43 PDT 2014
Adds support for devices with max page size smaller than the host's.
In the case we encounter such a host/device combination, the driver will
split a page into as many PRP entries as necessary for the device's page
size capabilities.
Signed-off-by: Keith Busch <keith.busch at intel.com>
---
Tested on a SPARC with 8k pages and an NVMe device with 4k max page
size supported.
drivers/block/nvme-core.c | 50 ++++++++++++++++++++++++++++-----------------
include/linux/nvme.h | 2 ++
2 files changed, 33 insertions(+), 19 deletions(-)
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index 02351e2..b4a0509 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -361,17 +361,17 @@ static __le64 **iod_list(struct nvme_iod *iod)
* as it only leads to a small amount of wasted memory for the lifetime of
* the I/O.
*/
-static int nvme_npages(unsigned size)
+static int nvme_npages(unsigned size, struct nvme_dev *dev)
{
- unsigned nprps = DIV_ROUND_UP(size + PAGE_SIZE, PAGE_SIZE);
- return DIV_ROUND_UP(8 * nprps, PAGE_SIZE - 8);
+ unsigned nprps = DIV_ROUND_UP(size + dev->page_size, dev->page_size);
+ return DIV_ROUND_UP(8 * nprps, dev->page_size - 8);
}
static struct nvme_iod *
-nvme_alloc_iod(unsigned nseg, unsigned nbytes, gfp_t gfp)
+nvme_alloc_iod(unsigned nseg, unsigned nbytes, gfp_t gfp, struct nvme_dev *dev)
{
struct nvme_iod *iod = kmalloc(sizeof(struct nvme_iod) +
- sizeof(__le64 *) * nvme_npages(nbytes) +
+ sizeof(__le64 *) * nvme_npages(nbytes, dev) +
sizeof(struct scatterlist) * nseg, gfp);
if (iod) {
@@ -388,7 +388,7 @@ nvme_alloc_iod(unsigned nseg, unsigned nbytes, gfp_t gfp)
void nvme_free_iod(struct nvme_dev *dev, struct nvme_iod *iod)
{
- const int last_prp = PAGE_SIZE / 8 - 1;
+ const int last_prp = dev->page_size / 8 - 1;
int i;
__le64 **list = iod_list(iod);
dma_addr_t prp_dma = iod->first_dma;
@@ -479,26 +479,27 @@ int nvme_setup_prps(struct nvme_dev *dev, struct nvme_iod *iod, int total_len,
__le64 **list = iod_list(iod);
dma_addr_t prp_dma;
int nprps, i;
+ u32 page_size = dev->page_size;
- length -= (PAGE_SIZE - offset);
+ length -= (page_size - offset);
if (length <= 0)
return total_len;
- dma_len -= (PAGE_SIZE - offset);
+ dma_len -= (page_size - offset);
if (dma_len) {
- dma_addr += (PAGE_SIZE - offset);
+ dma_addr += (page_size - offset);
} else {
sg = sg_next(sg);
dma_addr = sg_dma_address(sg);
dma_len = sg_dma_len(sg);
}
- if (length <= PAGE_SIZE) {
+ if (length <= page_size) {
iod->first_dma = dma_addr;
return total_len;
}
- nprps = DIV_ROUND_UP(length, PAGE_SIZE);
+ nprps = DIV_ROUND_UP(length, page_size);
if (nprps <= (256 / 8)) {
pool = dev->prp_small_pool;
iod->npages = 0;
@@ -511,13 +512,13 @@ int nvme_setup_prps(struct nvme_dev *dev, struct nvme_iod *iod, int total_len,
if (!prp_list) {
iod->first_dma = dma_addr;
iod->npages = -1;
- return (total_len - length) + PAGE_SIZE;
+ return (total_len - length) + page_size;
}
list[0] = prp_list;
iod->first_dma = prp_dma;
i = 0;
for (;;) {
- if (i == PAGE_SIZE / 8) {
+ if (i == page_size >> 3) {
__le64 *old_prp_list = prp_list;
prp_list = dma_pool_alloc(pool, gfp, &prp_dma);
if (!prp_list)
@@ -528,9 +529,9 @@ int nvme_setup_prps(struct nvme_dev *dev, struct nvme_iod *iod, int total_len,
i = 1;
}
prp_list[i++] = cpu_to_le64(dma_addr);
- dma_len -= PAGE_SIZE;
- dma_addr += PAGE_SIZE;
- length -= PAGE_SIZE;
+ dma_len -= page_size;
+ dma_addr += page_size;
+ length -= page_size;
if (length <= 0)
break;
if (dma_len > 0)
@@ -737,7 +738,7 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
if ((bio->bi_rw & REQ_FLUSH) && psegs)
return nvme_split_flush_data(nvmeq, bio);
- iod = nvme_alloc_iod(psegs, bio->bi_iter.bi_size, GFP_ATOMIC);
+ iod = nvme_alloc_iod(psegs, bio->bi_iter.bi_size, GFP_ATOMIC, ns->dev);
if (!iod)
return -ENOMEM;
@@ -1450,6 +1451,15 @@ static int nvme_configure_admin_queue(struct nvme_dev *dev)
u32 aqa;
u64 cap = readq(&dev->bar->cap);
struct nvme_queue *nvmeq;
+ unsigned page_shift = PAGE_SHIFT;
+ unsigned dev_page_shift = NVME_CAP_MPSMAX(cap) + 12;
+
+ if (page_shift > dev_page_shift) {
+ dev_warn(&dev->pci_dev->dev,
+ "host/device page size mismatch %u/%u\n",
+ 1 << page_shift, 1 << dev_page_shift);
+ page_shift = dev_page_shift;
+ }
result = nvme_disable_ctrl(dev, cap);
if (result < 0)
@@ -1465,8 +1475,10 @@ static int nvme_configure_admin_queue(struct nvme_dev *dev)
aqa = nvmeq->q_depth - 1;
aqa |= aqa << 16;
+ dev->page_size = 1 << page_shift;
+
dev->ctrl_config = NVME_CC_ENABLE | NVME_CC_CSS_NVM;
- dev->ctrl_config |= (PAGE_SHIFT - 12) << NVME_CC_MPS_SHIFT;
+ dev->ctrl_config |= (page_shift - 12) << NVME_CC_MPS_SHIFT;
dev->ctrl_config |= NVME_CC_ARB_RR | NVME_CC_SHN_NONE;
dev->ctrl_config |= NVME_CC_IOSQES | NVME_CC_IOCQES;
@@ -1516,7 +1528,7 @@ struct nvme_iod *nvme_map_user_pages(struct nvme_dev *dev, int write,
}
err = -ENOMEM;
- iod = nvme_alloc_iod(count, length, GFP_KERNEL);
+ iod = nvme_alloc_iod(count, length, GFP_KERNEL, dev);
if (!iod)
goto put_pages;
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 2bf4031..2a1dcaf 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -38,6 +38,7 @@ struct nvme_bar {
#define NVME_CAP_TIMEOUT(cap) (((cap) >> 24) & 0xff)
#define NVME_CAP_STRIDE(cap) (((cap) >> 32) & 0xf)
#define NVME_CAP_MPSMIN(cap) (((cap) >> 48) & 0xf)
+#define NVME_CAP_MPSMAX(cap) (((cap) >> 52) & 0xf)
enum {
NVME_CC_ENABLE = 1 << 0,
@@ -97,6 +98,7 @@ struct nvme_dev {
char firmware_rev[8];
u32 max_hw_sectors;
u32 stripe_size;
+ u32 page_size;
u16 oncs;
u16 abort_limit;
u8 vwc;
--
1.7.10.4
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