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nfs: migrate direct I/O to iov_iter_extract_pages

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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 <praan@google.com>
Reviewed-by: Shivaji Kant <shivajikant@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <anna.schumaker@hammerspace.com>
This commit is contained in:
Pranjal Shrivastava 2026-08-14 14:32:54 +00:00 committed by Anna Schumaker
parent 43280750bc
commit a2bb86ade0
1 changed files with 19 additions and 18 deletions
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37
fs/nfs/direct.c
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@ -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;