Le 28/09/2026 à 15:32, Pavel Begunkov a écrit :

Enable BIO_DMABUF_MAP backed requests. On registration we map the dma-buf and store it as a prp list, which is then used to initialise requests. All attached contexts are stored in a new list dmabuf_ctxs, and additions/removals are synchronised with dmabuf_lock.

Suggested-by: Keith Busch kbusch@kernel.org Signed-off-by: Pavel Begunkov asml.silence@gmail.com

Hi,

a few nitpick below, should it help.

---

drivers/nvme/host/core.c | 12 ++ drivers/nvme/host/nvme.h | 2 + drivers/nvme/host/pci.c | 308 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 322 insertions(+)

[...]

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index a953c0697f99..e58bdd9a4098 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -27,6 +27,8 @@ #include <linux/io-64-nonatomic-lo-hi.h> #include <linux/io-64-nonatomic-hi-lo.h> #include <linux/sed-opal.h> +#include <linux/dma-buf-io.h> +#include <linux/dma-resv.h>

Move up, to keep better alphabetical order ?

#include "trace.h" #include "nvme.h" @@ -318,6 +320,8 @@ struct nvme_dev { bool hmb; struct sg_table *hmb_sgt; mempool_t *dmavec_mempool;

• struct list_head dmabuf_ctxs;
• struct mutex dmabuf_lock;

/* shadow doorbell buffer support: */ __le32 *dbbuf_dbs; @@ -397,6 +401,13 @@ struct nvme_queue { struct completion delete_done; }; +struct nvme_dmabuf_map {

• struct dma_buf_io_map base;
• struct sg_table *sgt;
• unsigned nr_entries;
• dma_addr_t dma_list[];

Add __counted_by(nr_entries) and update nvme_dma_buf_io_map() so that nr_entries is set at the right time ?

+};

• /* bits for iod->flags */ enum nvme_iod_flags { /* this command has been aborted by the timeout handler */

...

+static struct dma_buf_io_map *nvme_dma_buf_io_map(struct dma_buf_io_ctx *ctx) +{

• unsigned nr_entries = ctx->dmabuf->size / NVME_CTRL_PAGE_SIZE;
• struct nvme_dma_buf_io_ctx *nvme_ctx = ctx->dev_priv;
• struct dma_buf_attachment *attach = nvme_ctx->attach;
• unsigned long tmp, i = 0;
• struct nvme_dmabuf_map *map;
• struct scatterlist *sg;
• struct sg_table *sgt;
• int ret;
• dma_resv_assert_held(ctx->dmabuf->resv);
• map = kvmalloc_flex(*map, dma_list, nr_entries);
• if (!map)

• return ERR_PTR(-ENOMEM);
  

• sgt = dma_buf_map_attachment(attach, ctx->dir);
• if (IS_ERR(sgt)) {

• ret = PTR_ERR(sgt);
  

• sgt = NULL;
  

• goto err;
  

• }
• for_each_sgtable_dma_sg(sgt, sg, tmp) {

• dma_addr_t dma_addr = sg_dma_address(sg);
  

• unsigned long sg_len = sg_dma_len(sg);
  

• if ((sg_len % NVME_CTRL_PAGE_SIZE) ||
  

•     (dma_addr % NVME_CTRL_PAGE_SIZE)) {
  

• 	ret = -EINVAL;
  

• 	goto err;
  

• }
  

• while (sg_len) {
  

• 	map->dma_list[i++] = dma_addr;
  

• 	dma_addr += NVME_CTRL_PAGE_SIZE;
  

• 	sg_len -= NVME_CTRL_PAGE_SIZE;
  

• }
  

• }
• ret = dma_buf_io_init_map(ctx, &map->base, sgt);
• if (ret)

• goto err;
  

• map->nr_entries = nr_entries;
• map->sgt = sgt;
• return &map->base;

+err:

• if (sgt)

• dma_buf_unmap_attachment(attach, sgt, ctx->dir);
  

• kfree(map);

kvfree()?

• return ERR_PTR(ret);

+}

...

CJ