From a2bb86ade0bc14446b3b5872c1513fdd35a15dbf Mon Sep 17 00:00:00 2001 From: Pranjal Shrivastava Date: Fri, 14 Aug 2026 14:32:54 +0000 Subject: [PATCH] nfs: migrate direct I/O to iov_iter_extract_pages Migrate the NFS Direct I/O path away from the legacy iov_iter_get_pages_alloc2() API to the modern iov_iter_extract_pages API. The transition aligns NFS with the modern VFS extraction model and serves as a preparatory step for supporting requirements such as page pinning via GUP for DMA. The migration fixes a bug in the Direct I/O loop where pages were being unpinned immediately after request creation. With the new extraction model, pins are held until the I/O is complete. Manual release in the loop is correspondingly updated to only clean up failed pages. Signed-off-by: Pranjal Shrivastava Reviewed-by: Shivaji Kant Reviewed-by: Christoph Hellwig Signed-off-by: Anna Schumaker --- fs/nfs/direct.c | 37 +++++++++++++++++++------------------ 1 file changed, 19 insertions(+), 18 deletions(-) diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 8b094f8ef087..59642e886a36 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -148,14 +148,8 @@ static void nfs_direct_file_adjust_size_locked(struct inode *inode, static void nfs_direct_release_pages(struct page **pages, unsigned int npages, bool pinned) { - unsigned int i; - - if (pinned) { + if (pinned) unpin_user_pages(pages, npages); - } else { - for (i = 0; i < npages; i++) - put_page(pages[i]); - } } void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo, @@ -334,16 +328,17 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, inode_dio_begin(inode); while (iov_iter_count(iter)) { - struct page **pagevec; + struct page **pagevec = NULL; size_t bytes; size_t pgbase; unsigned npages, i; + bool pinned = iov_iter_extract_will_pin(iter); - result = iov_iter_get_pages_alloc2(iter, &pagevec, - rsize, &pgbase); + result = iov_iter_extract_pages(iter, &pagevec, + rsize, ~0U, 0, &pgbase); if (result < 0) break; - + bytes = result; npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE; for (i = 0; i < npages; i++) { @@ -351,7 +346,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); /* XXX do we need to do the eof zeroing found in async_filler? */ req = nfs_page_create_from_page(dreq->ctx, pagevec[i], - false, pgbase, pos, + pinned, pgbase, pos, req_len); if (IS_ERR(req)) { result = PTR_ERR(req); @@ -360,6 +355,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, if (!nfs_pageio_add_request(&desc, req)) { result = desc.pg_error; nfs_release_request(req); + i++; break; } pgbase = 0; @@ -367,7 +363,8 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, requested_bytes += req_len; pos += req_len; } - nfs_direct_release_pages(pagevec, npages, false); + if (i < npages) + nfs_direct_release_pages(pagevec + i, npages - i, pinned); kvfree(pagevec); if (result < 0) break; @@ -871,13 +868,14 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, NFS_I(inode)->write_io += iov_iter_count(iter); while (iov_iter_count(iter)) { - struct page **pagevec; + struct page **pagevec = NULL; size_t bytes; size_t pgbase; unsigned npages, i; + bool pinned = iov_iter_extract_will_pin(iter); - result = iov_iter_get_pages_alloc2(iter, &pagevec, - wsize, &pgbase); + result = iov_iter_extract_pages(iter, &pagevec, + wsize, ~0U, 0, &pgbase); if (result < 0) break; @@ -888,7 +886,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); req = nfs_page_create_from_page(dreq->ctx, pagevec[i], - false, pgbase, pos, + pinned, pgbase, pos, req_len); if (IS_ERR(req)) { result = PTR_ERR(req); @@ -898,6 +896,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, if (desc.pg_error < 0) { nfs_free_request(req); result = desc.pg_error; + i++; break; } @@ -919,6 +918,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, if (desc.pg_error < 0 && desc.pg_error != -EAGAIN) { result = desc.pg_error; nfs_unlock_and_release_request(req); + i++; break; } @@ -932,7 +932,8 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, desc.pg_error = 0; defer = true; } - nfs_direct_release_pages(pagevec, npages, false); + if (i < npages) + nfs_direct_release_pages(pagevec + i, npages - i, pinned); kvfree(pagevec); if (result < 0) break;