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 <[email protected]>
Signed-off-by: Pavel Begunkov <[email protected]>
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
