Re: [RFC PATCH 18/35] libceph, rbd: Convert some page arrays to ceph_databuf

Viacheslav Dubeyko
2025-03-18T20:02:40Z

On Thu, 2025-03-13 at 23:33 +0000, David Howells wrote:
> Convert some miscellaneous page arrays to ceph_databuf containers.
>
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Viacheslav Dubeyko <slava@dubeyko.com>
> cc: Alex Markuze <amarkuze@redhat.com>
> cc: Ilya Dryomov <idryomov@gmail.com>
> cc: ceph-devel@vger.kernel.org
> cc: linux-fsdevel@vger.kernel.org
> ---
> drivers/block/rbd.c | 12 ++++-----
> include/linux/ceph/osd_client.h | 3 +++
> net/ceph/osd_client.c | 43 +++++++++++++++++++++------------
> 3 files changed, 36 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 078bb1e3e1da..eea12c7ab2a0 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -2108,7 +2108,7 @@ static int rbd_obj_calc_img_extents(struct rbd_obj_request *obj_req,
>
> static int rbd_osd_setup_stat(struct ceph_osd_request *osd_req, int which)
> {
> - struct page **pages;
> + struct ceph_databuf *dbuf;
>
> /*
> * The response data for a STAT call consists of:
> @@ -2118,14 +2118,12 @@ static int rbd_osd_setup_stat(struct ceph_osd_request *osd_req, int which)
> * le32 tv_nsec;
> * } mtime;
> */
> - pages = ceph_alloc_page_vector(1, GFP_NOIO);
> - if (IS_ERR(pages))
> - return PTR_ERR(pages);
> + dbuf = ceph_databuf_reply_alloc(1, 8 + sizeof(struct ceph_timespec), GFP_NOIO);

What this 8 + sizeof(struct ceph_timespec) means? Why do we use 8 here? :)

Thanks,
Slava.

> + if (!dbuf)
> + return -ENOMEM;
>
> osd_req_op_init(osd_req, which, CEPH_OSD_OP_STAT, 0);
> - osd_req_op_raw_data_in_pages(osd_req, which, pages,
> - 8 + sizeof(struct ceph_timespec),
> - 0, false, true);
> + osd_req_op_raw_data_in_databuf(osd_req, which, dbuf);
> return 0;
> }
>
> diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
> index d31e59bd128c..6e126e212271 100644
> --- a/include/linux/ceph/osd_client.h
> +++ b/include/linux/ceph/osd_client.h
> @@ -482,6 +482,9 @@ extern void osd_req_op_extent_osd_data_pages(struct ceph_osd_request *,
> struct page **pages, u64 length,
> u32 offset, bool pages_from_pool,
> bool own_pages);
> +void osd_req_op_raw_data_in_databuf(struct ceph_osd_request *osd_req,
> + unsigned int which,
> + struct ceph_databuf *databuf);
> extern void osd_req_op_extent_osd_data_pagelist(struct ceph_osd_request *,
> unsigned int which,
> struct ceph_pagelist *pagelist);
> diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
> index b4adb299f9cd..64a06267e7b3 100644
> --- a/net/ceph/osd_client.c
> +++ b/net/ceph/osd_client.c
> @@ -182,6 +182,17 @@ osd_req_op_extent_osd_data(struct ceph_osd_request *osd_req,
> }
> EXPORT_SYMBOL(osd_req_op_extent_osd_data);
>
> +void osd_req_op_raw_data_in_databuf(struct ceph_osd_request *osd_req,
> + unsigned int which,
> + struct ceph_databuf *dbuf)
> +{
> + struct ceph_osd_data *osd_data;
> +
> + osd_data = osd_req_op_raw_data_in(osd_req, which);
> + ceph_osd_databuf_init(osd_data, dbuf);
> +}
> +EXPORT_SYMBOL(osd_req_op_raw_data_in_databuf);
> +
> void osd_req_op_raw_data_in_pages(struct ceph_osd_request *osd_req,
> unsigned int which, struct page **pages,
> u64 length, u32 offset,
> @@ -5000,7 +5011,7 @@ int ceph_osdc_list_watchers(struct ceph_osd_client *osdc,
> u32 *num_watchers)
> {
> struct ceph_osd_request *req;
> - struct page **pages;
> + struct ceph_databuf *dbuf;
> int ret;
>
> req = ceph_osdc_alloc_request(osdc, NULL, 1, false, GFP_NOIO);
> @@ -5011,16 +5022,16 @@ int ceph_osdc_list_watchers(struct ceph_osd_client *osdc,
> ceph_oloc_copy(&req->r_base_oloc, oloc);
> req->r_flags = CEPH_OSD_FLAG_READ;
>
> - pages = ceph_alloc_page_vector(1, GFP_NOIO);
> - if (IS_ERR(pages)) {
> - ret = PTR_ERR(pages);
> + dbuf = ceph_databuf_reply_alloc(1, PAGE_SIZE, GFP_NOIO);
> + if (!dbuf) {
> + ret = -ENOMEM;
> goto out_put_req;
> }
>
> osd_req_op_init(req, 0, CEPH_OSD_OP_LIST_WATCHERS, 0);
> - ceph_osd_data_pages_init(osd_req_op_data(req, 0, list_watchers,
> - response_data),
> - pages, PAGE_SIZE, 0, false, true);
> + ceph_osd_databuf_init(osd_req_op_data(req, 0, list_watchers,
> + response_data),
> + dbuf);
>
> ret = ceph_osdc_alloc_messages(req, GFP_NOIO);
> if (ret)
> @@ -5029,10 +5040,11 @@ int ceph_osdc_list_watchers(struct ceph_osd_client *osdc,
> ceph_osdc_start_request(osdc, req);
> ret = ceph_osdc_wait_request(osdc, req);
> if (ret >= 0) {
> - void *p = page_address(pages[0]);
> + void *p = kmap_ceph_databuf_page(dbuf, 0);
> void *const end = p + req->r_ops[0].outdata_len;
>
> ret = decode_watchers(&p, end, watchers, num_watchers);
> + kunmap(p);
> }
>
> out_put_req:
> @@ -5246,12 +5258,12 @@ int osd_req_op_copy_from_init(struct ceph_osd_request *req,
> u8 copy_from_flags)
> {
> struct ceph_osd_req_op *op;
> - struct page **pages;
> + struct ceph_databuf *dbuf;
> void *p, *end;
>
> - pages = ceph_alloc_page_vector(1, GFP_KERNEL);
> - if (IS_ERR(pages))
> - return PTR_ERR(pages);
> + dbuf = ceph_databuf_req_alloc(1, PAGE_SIZE, GFP_KERNEL);
> + if (!dbuf)
> + return -ENOMEM;
>
> op = osd_req_op_init(req, 0, CEPH_OSD_OP_COPY_FROM2,
> dst_fadvise_flags);
> @@ -5260,16 +5272,17 @@ int osd_req_op_copy_from_init(struct ceph_osd_request *req,
> op->copy_from.flags = copy_from_flags;
> op->copy_from.src_fadvise_flags = src_fadvise_flags;
>
> - p = page_address(pages[0]);
> + p = kmap_ceph_databuf_page(dbuf, 0);
> end = p + PAGE_SIZE;
> ceph_encode_string(&p, src_oid->name, src_oid->name_len);
> encode_oloc(&p, src_oloc);
> ceph_encode_32(&p, truncate_seq);
> ceph_encode_64(&p, truncate_size);
> op->indata_len = PAGE_SIZE - (end - p);
> + ceph_databuf_added_data(dbuf, op->indata_len);
> + kunmap_local(p);
>
> - ceph_osd_data_pages_init(&op->copy_from.osd_data, pages,
> - op->indata_len, 0, false, true);
> + ceph_osd_databuf_init(&op->copy_from.osd_data, dbuf);
> return 0;
> }
> EXPORT_SYMBOL(osd_req_op_copy_from_init);
>
>