vfio/mlx5: Explicitly use number of pages instead of allocated length

allocated_length is a multiple of page size and number of pages,
so let's change the functions to accept number of pages. This improves
code readability, simplifies buffer handling, and enables combining DMA
send/receive operations, as will be introduced in the next patches.

Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Acked-by: Yishai Hadas <yishaih@nvidia.com>
Link: https://lore.kernel.org/r/76f39993d2ca0311b3bcfe56038a669d03926815.1747747694.git.leon@kernel.org
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
index 11eda6b207f13fe895e3693f6acd2d146d455f2b..377dee7765fb906ea71167fba62ba61e94b958a3 100644 (file)
--- a/drivers/vfio/pci/mlx5/cmd.c
+++ b/drivers/vfio/pci/mlx5/cmd.c
@@ -318,8 +318,7 @@ 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;
@@ -375,7 +374,7 @@ 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);
@@ -445,7 +444,7 @@ static int mlx5vf_add_migration_pages(struct mlx5_vhca_data_buffer *buf,
 
                if (ret)
                        goto err_append;
-               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,
@@ -464,8 +463,7 @@ err:
 }
 
 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;
@@ -477,9 +475,8 @@ 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;
 
@@ -505,8 +502,8 @@ 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;
@@ -521,7 +518,7 @@ 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;
                        }
@@ -535,7 +532,7 @@ 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,
@@ -716,7 +713,7 @@ 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);
 
@@ -738,8 +735,11 @@ 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);
+               header_buf = mlx5vf_get_data_buffer(
+                       migf,
+                       DIV_ROUND_UP(sizeof(struct mlx5_vf_migration_header),
+                                    PAGE_SIZE),
+                       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 df421dc6de04852c07cbabbf2e8bb78d3669aaa1..7d4a833b6900ae69b8549823549f8dbe2a1fe84c 100644 (file)
--- a/drivers/vfio/pci/mlx5/cmd.h
+++ b/drivers/vfio/pci/mlx5/cmd.h
@@ -56,7 +56,7 @@ 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;
@@ -217,12 +217,12 @@ 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);
 struct page *mlx5vf_get_migration_page(struct mlx5_vhca_data_buffer *buf,
                                       unsigned long offset);

diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
index 709543e7eb0428ca661ab900d6e6b4bf4361a438..bc0f468f741b4aaa28848a3b5e2bd970e289ef89 100644 (file)
--- a/drivers/vfio/pci/mlx5/main.c
+++ b/drivers/vfio/pci/mlx5/main.c
@@ -308,6 +308,7 @@ 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;
 
@@ -315,12 +316,11 @@ 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;
 
@@ -373,7 +373,8 @@ 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);
+       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);
 
@@ -388,7 +389,7 @@ 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);
@@ -437,15 +438,20 @@ 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;
                }
 
                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;
@@ -553,7 +559,8 @@ 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);
@@ -675,8 +682,8 @@ 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;
@@ -917,11 +924,14 @@ 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;
@@ -934,6 +944,7 @@ 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);
@@ -944,12 +955,13 @@ 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);
+                               migf->buf[0] = mlx5vf_alloc_data_buffer(
+                                       migf, npages, DMA_TO_DEVICE);
                                if (IS_ERR(migf->buf[0])) {
                                        ret = PTR_ERR(migf->buf[0]);
                                        migf->buf[0] = NULL;
@@ -1037,8 +1049,11 @@ mlx5vf_pci_resume_device_data(struct mlx5vf_pci_core_device *mvdev)
        }
 
        migf->buf[0] = buf;
-       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;
@@ -1148,7 +1163,8 @@ mlx5vf_pci_step_device_state_locked(struct mlx5vf_pci_core_device *mvdev,
                                        MLX5VF_QUERY_INC | MLX5VF_QUERY_CLEANUP);
                if (ret)
                        return ERR_PTR(ret);
-               buf = mlx5vf_get_data_buffer(migf, size, DMA_FROM_DEVICE);
+               buf = mlx5vf_get_data_buffer(migf,
+                               DIV_ROUND_UP(size, PAGE_SIZE), DMA_FROM_DEVICE);
                if (IS_ERR(buf))
                        return ERR_CAST(buf);
                /* pre_copy cleanup */