On Sat, Oct 01, 2022 at 05:23:25PM -0700, ira.weiny@intel.com wrote:
kiov = kcalloc(page_count, sizeof(*kiov), GFP_KERNEL); @@ -38,12 +39,12 @@ static int shm_get_kernel_pages(unsigned long start, size_t page_count, for (n = 0; n < page_count; n++) { kiov[n].iov_base = (void *)(start + n * PAGE_SIZE); kiov[n].iov_len = PAGE_SIZE;
pages[n] = virt_to_page(kiov[n].iov_base);get_page(pages[n]);
- rc = get_kernel_pages(kiov, page_count, 0, pages); kfree(kiov);
IDGI. The only thing in kiov[...] you are every reading is ->iov_base. And you fetch it once, right after the assignment.
Why bother with allocating the array at all? pages[n] = virt_to_page((void *)start + n * PAGE_SIZE); would do just as well, not to mention the fact that since you reject vmalloc and kmap, you might simply do
page = virt_to_page(start); for (int n = 0; n < page_count; n++) get_page(pages[n] = page + n);
instead...