[RFC 11/16] vfio/mlx5: Explicitly use number of pages instead of allocated length

Leon Romanovsky
2024-03-05T13:37:05Z

allocated_length is a multiple of page size and number of pages, so let's
change the functions to accept number of pages. It opens us a venue to
combine receive and send paths together with code readability
improvement.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
drivers/vfio/pci/mlx5/cmd.c | 31 ++++++++---------
drivers/vfio/pci/mlx5/cmd.h | 10 +++---
drivers/vfio/pci/mlx5/main.c | 65 +++++++++++++++++++++++-------------
3 files changed, 62 insertions(+), 44 deletions(-)

diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
index efd1d252cdc9..45104e47b7b2 100644
--- a/drivers/vfio/pci/mlx5/cmd.c
+++ b/drivers/vfio/pci/mlx5/cmd.c
@@ -305,8 +305,7 @@ static int _create_mkey(struct mlx5_core_dev *mdev, u32 pdn,
struct mlx5_vhca_recv_buf *recv_buf,
u32 *mkey)
{
- size_t npages = buf ? DIV_ROUND_UP(buf->allocated_length, PAGE_SIZE) :
- recv_buf->npages;
+ size_t npages = buf ? buf->npages : recv_buf->npages;
int err = 0, inlen;
__be64 *mtt;
void *mkc;
@@ -362,7 +361,7 @@ static int mlx5vf_dma_data_buffer(struct mlx5_vhca_data_buffer *buf)
if (mvdev->mdev_detach)
return -ENOTCONN;

- if (buf->dmaed || !buf->allocated_length)
+ if (buf->dmaed || !buf->npages)
return -EINVAL;

ret = dma_map_sgtable(mdev->device, &buf->table.sgt, buf->dma_dir, 0);
@@ -403,8 +402,7 @@ void mlx5vf_free_data_buffer(struct mlx5_vhca_data_buffer *buf)
}

struct mlx5_vhca_data_buffer *
-mlx5vf_alloc_data_buffer(struct mlx5_vf_migration_file *migf,
- size_t length,
+mlx5vf_alloc_data_buffer(struct mlx5_vf_migration_file *migf, u32 npages,
enum dma_data_direction dma_dir)
{
struct mlx5_vhca_data_buffer *buf;
@@ -416,9 +414,8 @@ mlx5vf_alloc_data_buffer(struct mlx5_vf_migration_file *migf,

buf->dma_dir = dma_dir;
buf->migf = migf;
- if (length) {
- ret = mlx5vf_add_migration_pages(buf,
- DIV_ROUND_UP_ULL(length, PAGE_SIZE));
+ if (npages) {
+ ret = mlx5vf_add_migration_pages(buf, npages);
if (ret)
goto end;

@@ -444,8 +441,8 @@ void mlx5vf_put_data_buffer(struct mlx5_vhca_data_buffer *buf)
}

struct mlx5_vhca_data_buffer *
-mlx5vf_get_data_buffer(struct mlx5_vf_migration_file *migf,
- size_t length, enum dma_data_direction dma_dir)
+mlx5vf_get_data_buffer(struct mlx5_vf_migration_file *migf, u32 npages,
+ enum dma_data_direction dma_dir)
{
struct mlx5_vhca_data_buffer *buf, *temp_buf;
struct list_head free_list;
@@ -460,7 +457,7 @@ mlx5vf_get_data_buffer(struct mlx5_vf_migration_file *migf,
list_for_each_entry_safe(buf, temp_buf, &migf->avail_list, buf_elm) {
if (buf->dma_dir == dma_dir) {
list_del_init(&buf->buf_elm);
- if (buf->allocated_length >= length) {
+ if (buf->npages >= npages) {
spin_unlock_irq(&migf->list_lock);
goto found;
}
@@ -474,7 +471,7 @@ mlx5vf_get_data_buffer(struct mlx5_vf_migration_file *migf,
}
}
spin_unlock_irq(&migf->list_lock);
- buf = mlx5vf_alloc_data_buffer(migf, length, dma_dir);
+ buf = mlx5vf_alloc_data_buffer(migf, npages, dma_dir);

found:
while ((temp_buf = list_first_entry_or_null(&free_list,
@@ -645,7 +642,7 @@ int mlx5vf_cmd_save_vhca_state(struct mlx5vf_pci_core_device *mvdev,
MLX5_SET(save_vhca_state_in, in, op_mod, 0);
MLX5_SET(save_vhca_state_in, in, vhca_id, mvdev->vhca_id);
MLX5_SET(save_vhca_state_in, in, mkey, buf->mkey);
- MLX5_SET(save_vhca_state_in, in, size, buf->allocated_length);
+ MLX5_SET(save_vhca_state_in, in, size, buf->npages * PAGE_SIZE);
MLX5_SET(save_vhca_state_in, in, incremental, inc);
MLX5_SET(save_vhca_state_in, in, set_track, track);

@@ -668,8 +665,12 @@ int mlx5vf_cmd_save_vhca_state(struct mlx5vf_pci_core_device *mvdev,
}

if (!header_buf) {
- header_buf = mlx5vf_get_data_buffer(migf,
- sizeof(struct mlx5_vf_migration_header), DMA_NONE);
+ u32 npages = DIV_ROUND_UP(
+ sizeof(struct mlx5_vf_migration_header),
+ PAGE_SIZE);
+
+ header_buf =
+ mlx5vf_get_data_buffer(migf, npages, DMA_NONE);
if (IS_ERR(header_buf)) {
err = PTR_ERR(header_buf);
goto err_free;
diff --git a/drivers/vfio/pci/mlx5/cmd.h b/drivers/vfio/pci/mlx5/cmd.h
index f2c7227fa683..887267ebbd8a 100644
--- a/drivers/vfio/pci/mlx5/cmd.h
+++ b/drivers/vfio/pci/mlx5/cmd.h
@@ -60,7 +60,7 @@ struct mlx5_vhca_data_buffer {
struct sg_append_table table;
loff_t start_pos;
u64 length;
- u64 allocated_length;
+ u32 npages;
u32 mkey;
enum dma_data_direction dma_dir;
u8 dmaed:1;
@@ -219,12 +219,12 @@ int mlx5vf_cmd_alloc_pd(struct mlx5_vf_migration_file *migf);
void mlx5vf_cmd_dealloc_pd(struct mlx5_vf_migration_file *migf);
void mlx5fv_cmd_clean_migf_resources(struct mlx5_vf_migration_file *migf);
struct mlx5_vhca_data_buffer *
-mlx5vf_alloc_data_buffer(struct mlx5_vf_migration_file *migf,
- size_t length, enum dma_data_direction dma_dir);
+mlx5vf_alloc_data_buffer(struct mlx5_vf_migration_file *migf, u32 npages,
+ enum dma_data_direction dma_dir);
void mlx5vf_free_data_buffer(struct mlx5_vhca_data_buffer *buf);
struct mlx5_vhca_data_buffer *
-mlx5vf_get_data_buffer(struct mlx5_vf_migration_file *migf,
- size_t length, enum dma_data_direction dma_dir);
+mlx5vf_get_data_buffer(struct mlx5_vf_migration_file *migf, u32 npages,
+ enum dma_data_direction dma_dir);
void mlx5vf_put_data_buffer(struct mlx5_vhca_data_buffer *buf);
int mlx5vf_add_migration_pages(struct mlx5_vhca_data_buffer *buf,
unsigned int npages);
diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
index fe09a8c8af95..b11b1c27d284 100644
--- a/drivers/vfio/pci/mlx5/main.c
+++ b/drivers/vfio/pci/mlx5/main.c
@@ -94,7 +94,7 @@ int mlx5vf_add_migration_pages(struct mlx5_vhca_data_buffer *buf,

if (ret)
goto err;
- buf->allocated_length += filled * PAGE_SIZE;
+ buf->npages += filled;
/* clean input for another bulk allocation */
memset(page_list, 0, filled * sizeof(*page_list));
to_fill = min_t(unsigned int, to_alloc,
@@ -352,6 +352,7 @@ static struct mlx5_vhca_data_buffer *
mlx5vf_mig_file_get_stop_copy_buf(struct mlx5_vf_migration_file *migf,
u8 index, size_t required_length)
{
+ u32 npages = DIV_ROUND_UP(required_length, PAGE_SIZE);
struct mlx5_vhca_data_buffer *buf = migf->buf[index];
u8 chunk_num;

@@ -359,12 +360,11 @@ mlx5vf_mig_file_get_stop_copy_buf(struct mlx5_vf_migration_file *migf,
chunk_num = buf->stop_copy_chunk_num;
buf->migf->buf[index] = NULL;
/* Checking whether the pre-allocated buffer can fit */
- if (buf->allocated_length >= required_length)
+ if (buf->npages >= npages)
return buf;

mlx5vf_put_data_buffer(buf);
- buf = mlx5vf_get_data_buffer(buf->migf, required_length,
- DMA_FROM_DEVICE);
+ buf = mlx5vf_get_data_buffer(buf->migf, npages, DMA_FROM_DEVICE);
if (IS_ERR(buf))
return buf;

@@ -417,7 +417,9 @@ static int mlx5vf_add_stop_copy_header(struct mlx5_vf_migration_file *migf,
u8 *to_buff;
int ret;

- header_buf = mlx5vf_get_data_buffer(migf, size, DMA_NONE);
+ BUILD_BUG_ON(size > PAGE_SIZE);
+ header_buf = mlx5vf_get_data_buffer(migf, DIV_ROUND_UP(size, PAGE_SIZE),
+ DMA_NONE);
if (IS_ERR(header_buf))
return PTR_ERR(header_buf);

@@ -432,7 +434,7 @@ static int mlx5vf_add_stop_copy_header(struct mlx5_vf_migration_file *migf,
to_buff = kmap_local_page(page);
memcpy(to_buff, &header, sizeof(header));
header_buf->length = sizeof(header);
- data.stop_copy_size = cpu_to_le64(migf->buf[0]->allocated_length);
+ data.stop_copy_size = cpu_to_le64(migf->buf[0]->npages * PAGE_SIZE);
memcpy(to_buff + sizeof(header), &data, sizeof(data));
header_buf->length += sizeof(data);
kunmap_local(to_buff);
@@ -481,15 +483,22 @@ static int mlx5vf_prep_stop_copy(struct mlx5vf_pci_core_device *mvdev,

num_chunks = mvdev->chunk_mode ? MAX_NUM_CHUNKS : 1;
for (i = 0; i < num_chunks; i++) {
- buf = mlx5vf_get_data_buffer(migf, inc_state_size, DMA_FROM_DEVICE);
+ buf = mlx5vf_get_data_buffer(
+ migf, DIV_ROUND_UP(inc_state_size, PAGE_SIZE),
+ DMA_FROM_DEVICE);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto err;
}

+ BUILD_BUG_ON(sizeof(struct mlx5_vf_migration_header) >
+ PAGE_SIZE);
migf->buf[i] = buf;
- buf = mlx5vf_get_data_buffer(migf,
- sizeof(struct mlx5_vf_migration_header), DMA_NONE);
+ buf = mlx5vf_get_data_buffer(
+ migf,
+ DIV_ROUND_UP(sizeof(struct mlx5_vf_migration_header),
+ PAGE_SIZE),
+ DMA_NONE);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto err;
@@ -597,7 +606,8 @@ static long mlx5vf_precopy_ioctl(struct file *filp, unsigned int cmd,
* We finished transferring the current state and the device has a
* dirty state, save a new state to be ready for.
*/
- buf = mlx5vf_get_data_buffer(migf, inc_length, DMA_FROM_DEVICE);
+ buf = mlx5vf_get_data_buffer(migf, DIV_ROUND_UP(inc_length, PAGE_SIZE),
+ DMA_FROM_DEVICE);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
mlx5vf_mark_err(migf);
@@ -718,8 +728,8 @@ mlx5vf_pci_save_device_data(struct mlx5vf_pci_core_device *mvdev, bool track)

if (track) {
/* leave the allocated buffer ready for the stop-copy phase */
- buf = mlx5vf_alloc_data_buffer(migf,
- migf->buf[0]->allocated_length, DMA_FROM_DEVICE);
+ buf = mlx5vf_alloc_data_buffer(migf, migf->buf[0]->npages,
+ DMA_FROM_DEVICE);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto out_pd;
@@ -783,16 +793,15 @@ mlx5vf_resume_read_image_no_header(struct mlx5_vhca_data_buffer *vhca_buf,
const char __user **buf, size_t *len,
loff_t *pos, ssize_t *done)
{
+ u32 npages = DIV_ROUND_UP(requested_length, PAGE_SIZE);
int ret;

if (requested_length > MAX_LOAD_SIZE)
return -ENOMEM;

- if (vhca_buf->allocated_length < requested_length) {
- ret = mlx5vf_add_migration_pages(
- vhca_buf,
- DIV_ROUND_UP(requested_length - vhca_buf->allocated_length,
- PAGE_SIZE));
+ if (vhca_buf->npages < npages) {
+ ret = mlx5vf_add_migration_pages(vhca_buf,
+ npages - vhca_buf->npages);
if (ret)
return ret;
}
@@ -992,11 +1001,14 @@ static ssize_t mlx5vf_resume_write(struct file *filp, const char __user *buf,
goto out_unlock;
break;
case MLX5_VF_LOAD_STATE_PREP_HEADER_DATA:
- if (vhca_buf_header->allocated_length < migf->record_size) {
+ {
+ u32 npages = DIV_ROUND_UP(migf->record_size, PAGE_SIZE);
+
+ if (vhca_buf_header->npages < npages) {
mlx5vf_free_data_buffer(vhca_buf_header);

- migf->buf_header[0] = mlx5vf_alloc_data_buffer(migf,
- migf->record_size, DMA_NONE);
+ migf->buf_header[0] = mlx5vf_alloc_data_buffer(
+ migf, npages, DMA_NONE);
if (IS_ERR(migf->buf_header[0])) {
ret = PTR_ERR(migf->buf_header[0]);
migf->buf_header[0] = NULL;
@@ -1009,6 +1021,7 @@ static ssize_t mlx5vf_resume_write(struct file *filp, const char __user *buf,
vhca_buf_header->start_pos = migf->max_pos;
migf->load_state = MLX5_VF_LOAD_STATE_READ_HEADER_DATA;
break;
+ }
case MLX5_VF_LOAD_STATE_READ_HEADER_DATA:
ret = mlx5vf_resume_read_header_data(migf, vhca_buf_header,
&buf, &len, pos, &done);
@@ -1019,12 +1032,13 @@ static ssize_t mlx5vf_resume_write(struct file *filp, const char __user *buf,
{
u64 size = max(migf->record_size,
migf->stop_copy_prep_size);
+ u32 npages = DIV_ROUND_UP(size, PAGE_SIZE);

- if (vhca_buf->allocated_length < size) {
+ if (vhca_buf->npages < npages) {
mlx5vf_free_data_buffer(vhca_buf);

migf->buf[0] = mlx5vf_alloc_data_buffer(migf,
- size, DMA_TO_DEVICE);
+ npages, DMA_TO_DEVICE);
if (IS_ERR(migf->buf[0])) {
ret = PTR_ERR(migf->buf[0]);
migf->buf[0] = NULL;
@@ -1115,8 +1129,11 @@ mlx5vf_pci_resume_device_data(struct mlx5vf_pci_core_device *mvdev)

migf->buf[0] = buf;
if (MLX5VF_PRE_COPY_SUPP(mvdev)) {
- buf = mlx5vf_alloc_data_buffer(migf,
- sizeof(struct mlx5_vf_migration_header), DMA_NONE);
+ buf = mlx5vf_alloc_data_buffer(
+ migf,
+ DIV_ROUND_UP(sizeof(struct mlx5_vf_migration_header),
+ PAGE_SIZE),
+ DMA_NONE);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto out_buf;
--
2.44.0