Hi, On 03/30/2016 09:09 PM, Boris BREZILLON wrote: [...] > +int sg_alloc_table_from_buf(struct sg_table *sgt, const void *buf, size_t len, > + const struct sg_constraints *constraints, > + gfp_t gfp_mask) > +{ > + struct sg_constraints cons = { }; > + size_t remaining, chunk_len; > + const void *sg_buf; > + int i, ret; > + > + if (constraints) > + cons = *constraints; > + > + ret = sg_check_constraints(&cons, buf, len); > + if (ret) > + return ret; > + > + sg_buf = buf; > + remaining = len; > + i = 0; > + sg_for_each_chunk_in_buf(sg_buf, remaining, chunk_len, &cons) > + i++; > + > + ret = sg_alloc_table(sgt, i, gfp_mask); > + if (ret) > + return ret; > + > + sg_buf = buf; > + remaining = len; > + i = 0; > + sg_for_each_chunk_in_buf(sg_buf, remaining, chunk_len, &cons) { > + if (is_vmalloc_addr(sg_buf)) { > + struct page *vm_page; > + > + vm_page = vmalloc_to_page(sg_buf); > + if (!vm_page) { > + ret = -ENOMEM; > + goto err_free_table; > + } > + > + sg_set_page(&sgt->sgl[i], vm_page, chunk_len, > + offset_in_page(sg_buf)); > + } else { > + sg_set_buf(&sgt->sgl[i], sg_buf, chunk_len); > + } > + If the buf address is in PKMAP_BASE - PAGE_OFFSET-1 region (I have observed that JFFS2 FS provides buffers in above region to MTD layer), if CONFIG_DEBUG_SG is set then sg_set_buf() will throw a BUG_ON() as virt_addr_is_valid() will return false. Is there a sane way to handle buffers of PKMAP_BASE region with sg_* APIs? Or, is the function sg_alloc_table_from_buf() not to be used with such buffers? -- Regards Vignesh -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html