Anj Duvnjak reports that the Kodi.tv NFS client is not able to read video files from a v5.10.11 Linux NFS server. The new sendpage-based TCP sendto logic was not attentive to non- zero page_base values. nfsd_splice_read() sets that field when a READ payload starts in the middle of a page. The Linux NFS client rarely emits an NFS READ that is not page- aligned. All of my testing so far has been with Linux clients, so I missed this one. Reported-by: A. Duvnjak <avian@xxxxxxxxxxxxxxxx> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=211471 Fixes: 4a85a6a3320b ("SUNRPC: Handle TCP socket sends with kernel_sendpage() again") Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- net/sunrpc/svcsock.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index c9766d07eb81..5a809c64dc7b 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -1113,14 +1113,15 @@ static int svc_tcp_sendmsg(struct socket *sock, struct msghdr *msg, unsigned int offset, len, remaining; struct bio_vec *bvec; - bvec = xdr->bvec; - offset = xdr->page_base; + bvec = xdr->bvec + (xdr->page_base >> PAGE_SHIFT); + offset = offset_in_page(xdr->page_base); remaining = xdr->page_len; flags = MSG_MORE | MSG_SENDPAGE_NOTLAST; while (remaining > 0) { if (remaining <= PAGE_SIZE && tail->iov_len == 0) flags = 0; - len = min(remaining, bvec->bv_len); + + len = min(remaining, bvec->bv_len - offset); ret = kernel_sendpage(sock, bvec->bv_page, bvec->bv_offset + offset, len, flags);
