From 2dad0b15bbe86ffa6d2f234c40609aa59894e9ec Mon Sep 17 00:00:00 2001 From: Stefan Metzmacher Date: Mon, 15 Sep 2025 00:55:31 +0200 Subject: [PATCH] smb: client: let smbd_post_send_iter() call ib_dma_map_single() for the header first This will simplify further changes, the important part is that request->num_sge >= 1 is only set if request->sge[0].* is valid. Note that ib_dma_sync_single_for_device() is called in smbd_post_send() for each sge, so the device will still see the packet header even if it's modified after calling ib_dma_map_single(). Cc: Steve French Cc: Tom Talpey Cc: Long Li Acked-by: Namjae Jeon Cc: linux-cifs@vger.kernel.org Cc: samba-technical@lists.samba.org Signed-off-by: Stefan Metzmacher Signed-off-by: Steve French --- fs/smb/client/smbdirect.c | 43 +++++++++++++++++++-------------------- 1 file changed, 21 insertions(+), 22 deletions(-) diff --git a/fs/smb/client/smbdirect.c b/fs/smb/client/smbdirect.c index 1d81ead875d0a..316f398c70f4b 100644 --- a/fs/smb/client/smbdirect.c +++ b/fs/smb/client/smbdirect.c @@ -1158,10 +1158,30 @@ wait_send_queue: request->socket = sc; memset(request->sge, 0, sizeof(request->sge)); + /* Map the packet to DMA */ + header_length = sizeof(struct smbdirect_data_transfer); + /* If this is a packet without payload, don't send padding */ + if (!iter) + header_length = offsetof(struct smbdirect_data_transfer, padding); + + packet = smbdirect_send_io_payload(request); + request->sge[0].addr = ib_dma_map_single(sc->ib.dev, + (void *)packet, + header_length, + DMA_TO_DEVICE); + if (ib_dma_mapping_error(sc->ib.dev, request->sge[0].addr)) { + rc = -EIO; + goto err_dma; + } + + request->sge[0].length = header_length; + request->sge[0].lkey = sc->ib.pd->local_dma_lkey; + request->num_sge = 1; + /* Fill in the data payload to find out how much data we can add */ if (iter) { struct smb_extract_to_rdma extract = { - .nr_sge = 1, + .nr_sge = request->num_sge, .max_sge = SMBDIRECT_SEND_IO_MAX_SGE, .sge = request->sge, .device = sc->ib.dev, @@ -1180,11 +1200,9 @@ wait_send_queue: *_remaining_data_length -= data_length; } else { data_length = 0; - request->num_sge = 1; } /* Fill in the packet header */ - packet = smbdirect_send_io_payload(request); packet->credits_requested = cpu_to_le16(sp->send_credit_target); new_credits = manage_credits_prior_sending(sc); @@ -1211,25 +1229,6 @@ wait_send_queue: le32_to_cpu(packet->data_length), le32_to_cpu(packet->remaining_data_length)); - /* Map the packet to DMA */ - header_length = sizeof(struct smbdirect_data_transfer); - /* If this is a packet without payload, don't send padding */ - if (!data_length) - header_length = offsetof(struct smbdirect_data_transfer, padding); - - request->sge[0].addr = ib_dma_map_single(sc->ib.dev, - (void *)packet, - header_length, - DMA_TO_DEVICE); - if (ib_dma_mapping_error(sc->ib.dev, request->sge[0].addr)) { - rc = -EIO; - request->sge[0].addr = 0; - goto err_dma; - } - - request->sge[0].length = header_length; - request->sge[0].lkey = sc->ib.pd->local_dma_lkey; - rc = smbd_post_send(sc, request); if (!rc) return 0; -- 2.47.3