On Mon, May 19, 2025 at 9:57 AM Herbert Xu herbert@gondor.apana.org.au wrote:
On Wed, May 14, 2025 at 10:40:42AM +0530, Bharat Bhushan wrote:
@@ -429,22 +431,50 @@ otx2_sg_info_create(struct pci_dev *pdev, struct otx2_cpt_req_info *req, return NULL; }
g_sz_bytes = ((req->in_cnt + 3) / 4) *sizeof(struct otx2_cpt_sglist_component);s_sz_bytes = ((req->out_cnt + 3) / 4) *sizeof(struct otx2_cpt_sglist_component);
/* Allocate memory to meet below alignment requirement:* ----------------------------------* | struct otx2_cpt_inst_info |* | (No alignment required) |* | -----------------------------|* | | padding for 8B alignment |* |----------------------------------|* | SG List Gather/Input memory |* | Length = multiple of 32Bytes |* | Alignment = 8Byte |* |----------------------------------|* | SG List Scatter/Output memory |* | Length = multiple of 32Bytes |* | Alignment = 8Byte |* | (padding for below alignment) |* | -----------------------------|* | | padding for 32B alignment |* |----------------------------------|* | Result response memory |* ----------------------------------*/
dlen = g_sz_bytes + s_sz_bytes + SG_LIST_HDR_SIZE;align_dlen = ALIGN(dlen, align);info_len = ALIGN(sizeof(*info), align);total_mem_len = align_dlen + info_len + sizeof(union otx2_cpt_res_s);
info_len = sizeof(*info);g_len = ((req->in_cnt + 3) / 4) *sizeof(struct otx2_cpt_sglist_component);s_len = ((req->out_cnt + 3) / 4) *sizeof(struct otx2_cpt_sglist_component);dlen = g_len + s_len + SG_LIST_HDR_SIZE;/* Allocate extra memory for SG and response address alignment */total_mem_len = ALIGN(info_len, OTX2_CPT_DPTR_RPTR_ALIGN) + dlen;
This add extra memory for 8-byte (OTX2_CPT_DPTR_RPTR_ALIGN) alignment
total_mem_len = ALIGN(total_mem_len, OTX2_CPT_RES_ADDR_ALIGN) +sizeof(union otx2_cpt_res_s);
This add extra memory for 32-byte (OTX2_CPT_RES_ADDR_ALIGN)) In case not observed, OTX2_CPT_RES_ADDR_ALIGN is not the same as OTX2_CPT_DPTR_RPTR_ALIGN.
This doesn't look right. It would be correct if kzalloc returned a 32-byte aligned pointer to start with. But it doesn't anymore, which is why you're making this patch in the first place :)
So you need to add extra memory to bridge the gap between what it returns and what you expect. Since it returns 8-byte aligned memory, and you expect 32-byte aligned pointers, you should add 24 bytes.
IOW the calculation should be:
total_mem_len = ALIGN(info_len, OTX2_CPT_DPTR_RPTR_ALIGN) + dlen; total_mem_len = ALIGN(total_mem_len, OTX2_CPT_DPTR_RPTR_ALIGN); total_mem_len += (OTX2_CPT_RES_ADDR_ALIGN - 1) & ~(OTX2_CPT_DPTR_RPTR_ALIGN - 1);info = kzalloc(total_mem_len, gfp); if (unlikely(!info)) return NULL; info->dlen = dlen;
info->in_buffer = (u8 *)info + info_len;
info->in_buffer = PTR_ALIGN((u8 *)info + info_len,OTX2_CPT_DPTR_RPTR_ALIGN);info->out_buffer = info->in_buffer + 8 + g_len;I presume the 8 here corresponds to SG_LIST_HDR_SIZE from the dlen calculation above. If so please spell it out as otherwise it's just confusing.
Yes, this is for SG_LIST_HDR_SIZE, will use same here.
Thanks -Bharat
Cheers,
Email: Herbert Xu herbert@gondor.apana.org.au Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt