nfs: Modernize Direct I/O path

It would be nice to avoid the overly long lines, but otherwise this looks good.

Nit: capitalization of the patch subjects is inconsistent. You probably one to stick to one version or another.

Otherwise this looks good to me.

Introduce a centralized helper, nfs_release_request_list, to handle the bulk release of nfs_page requests from a list.

This serves as a preparatory step for two upcoming improvements:

1. Pin-Aware Cleanup: As we migrate to iov_iter_extract_* API, requests will hold pins (GUP) instead of standard references. The helper ensures that the correct unpinning logic gets applied consistently across all requests in a list.

2. Folio Support: In subsequent patches where nfs_page structures will cover multi-page folios, this helper provides a clean infrastructure to unlock these larger units of I/O in bulk during completion, similat to the pattern in bio_release_pages.

Additionally, refactor nfs_read_sync_pgio_error() to utilize this new helper.

Signed-off-by Pranjal Shrivastava <[email protected]>

---
 fs/nfs/direct.c          |  8 +-------
 fs/nfs/pagelist.c        | 18 ++++++++++++++++++
 include/linux/nfs_page.h |  4 ++--
 3 files changed, 21 insertions(+), 9 deletions(-)

fs/nfs/direct.c +1 -7

index 19792a38c924..96995736fac2 100644
@@ -314,13 +314,7 @@ static void nfs_direct_read_completion(struct nfs_pgio_header *hdr)
 
 static void nfs_read_sync_pgio_error(struct list_head *head, int error)
 {
-	struct nfs_page *req;
-
-	while (!list_empty(head)) {
-		req = nfs_list_entry(head->next);
-		nfs_list_remove_request(req);
-		nfs_release_request(req);
-	}
+	nfs_release_request_list(head);
 }
 
 static void nfs_direct_pgio_init(struct nfs_pgio_header *hdr)

fs/nfs/pagelist.c +2 -0

index 7d51e10fe97a..569bac4faff7 100644
@@ -622,6 +622,24 @@ void nfs_release_request(struct nfs_page *req)
 }
 EXPORT_SYMBOL_GPL(nfs_release_request);
 
+/*
+ * nfs_release_request_list - Release a list of NFS read/write requests

Quoted 10 lines · Pranjal Shrivastava

Introduce a centralized helper, nfs_release_request_list, to handle the bulk release of nfs_page requests from a list.

This serves as a preparatory step for two upcoming improvements:

1. Pin-Aware Cleanup: As we migrate to iov_iter_extract_* API, requests will hold pins (GUP) instead of standard references. The helper ensures that the correct unpinning logic gets applied consistently across all requests in a list.

Quoted 4 lines

2. Folio Support: In subsequent patches where nfs_page structures will cover multi-page folios, this helper provides a clean infrastructure to unlock these larger units of I/O in bulk during completion, similat to the pattern in bio_release_pages.

Quoted 40 lines

Additionally, refactor nfs_read_sync_pgio_error() to utilize this new helper.

Signed-off-by Pranjal Shrivastava <[email protected]>

---
 fs/nfs/direct.c          |  8 +-------
 fs/nfs/pagelist.c        | 18 ++++++++++++++++++
 include/linux/nfs_page.h |  4 ++--
 3 files changed, 21 insertions(+), 9 deletions(-)

fs/nfs/direct.c +1 -7

index 19792a38c924..96995736fac2 100644
@@ -314,13 +314,7 @@ static void nfs_direct_read_completion(struct nfs_pgio_header *hdr)
 
 static void nfs_read_sync_pgio_error(struct list_head *head, int error)
 {
-     struct nfs_page *req;
-
-     while (!list_empty(head)) {
-             req = nfs_list_entry(head->next);
-             nfs_list_remove_request(req);
-             nfs_release_request(req);
-     }
+     nfs_release_request_list(head);
 }
 
 static void nfs_direct_pgio_init(struct nfs_pgio_header *hdr)

fs/nfs/pagelist.c +2 -0

index 7d51e10fe97a..569bac4faff7 100644
@@ -622,6 +622,24 @@ void nfs_release_request(struct nfs_page *req)
 }
 EXPORT_SYMBOL_GPL(nfs_release_request);
 
+/*
+ * nfs_release_request_list - Release a list of NFS read/write requests

fs/nfs/pagelist.c void nfs_release_request(struct nfs_page *req) · line 636

Quoted 10 lines

fs/nfs/pagelist.c +10 -0

+ * @head: list of requests to release
+ *
+ * Removes each request from the list and drops it's refcount.
+ */
+void nfs_release_request_list(struct list_head *head)
+{
+     struct nfs_page *req;
+
+     while (!list_empty(head)) {
+             req = nfs_list_entry(head->next);

req could/should be local here. Or you switch to list_first_or_null, which some folks prefer.

fs/nfs/pagelist.c void nfs_release_request(struct nfs_page *req) · line 638

Quoted 2 lines

fs/nfs/pagelist.c +2 -0

+extern void nfs_release_request(struct nfs_page *req);
+extern void nfs_release_request_list(struct list_head *head);

Please drop the superflous externs for new code.

Quoted 12 lines · Christoph Hellwig

Quoted 10 lines · Pranjal Shrivastava

Introduce a centralized helper, nfs_release_request_list, to handle the bulk release of nfs_page requests from a list.

This serves as a preparatory step for two upcoming improvements:

1. Pin-Aware Cleanup: As we migrate to iov_iter_extract_* API, requests will hold pins (GUP) instead of standard references. The helper ensures that the correct unpinning logic gets applied consistently across all requests in a list.

Quoted 4 lines

Quoted 4 lines

2. Folio Support: In subsequent patches where nfs_page structures will cover multi-page folios, this helper provides a clean infrastructure to unlock these larger units of I/O in bulk during completion, similat to the pattern in bio_release_pages.

nit: similar -> similar

Quoted 16 lines

fs/nfs/pagelist.c void nfs_release_request(struct nfs_page *req) · line 636

Quoted 12 lines

fs/nfs/pagelist.c +12 -0

+/*
+ * nfs_release_request_list - Release a list of NFS read/write requests
+ * @head: list of requests to release
+ *
+ * Removes each request from the list and drops it's refcount.
+ */
+void nfs_release_request_list(struct list_head *head)
+{
+     struct nfs_page *req;
+
+     while (!list_empty(head)) {
+             req = nfs_list_entry(head->next);

req could/should be local here. Or you switch to list_first_or_null, which some folks prefer.

Quoted 5 lines

include/linux/nfs_page.h extern struct nfs_page *nfs_page_create_from_folio(struct nfs_open_context *ctx, · line 140

Quoted 2 lines

include/linux/nfs_page.h +2 -0

+extern void nfs_release_request(struct nfs_page *req);
+extern void nfs_release_request_list(struct list_head *head);

Please drop the superflous externs for new code.

Small nit + fix christoph's comment,
else looks ok

Reviewed-by Shivaji Kant <[email protected]>

Quoted 18 lines · Pranjal Shrivastava

Introduce a centralized helper, nfs_release_request_list, to handle the bulk release of nfs_page requests from a list.

This serves as a preparatory step for two upcoming improvements:

1. Pin-Aware Cleanup: As we migrate to iov_iter_extract_* API, requests will hold pins (GUP) instead of standard references. The helper ensures that the correct unpinning logic gets applied consistently across all requests in a list.

2. Folio Support: In subsequent patches where nfs_page structures will cover multi-page folios, this helper provides a clean infrastructure to unlock these larger units of I/O in bulk during completion, similat to the pattern in bio_release_pages.

Additionally, refactor nfs_read_sync_pgio_error() to utilize this new helper.

Quoted 7 lines

fs/nfs/pagelist.c +7 -0

+/*
+ * nfs_release_request_list - Release a list of NFS read/write requests
+ * @head: list of requests to release
+ *
+ * Removes each request from the list and drops it's refcount.
+ */
+void nfs_release_request_list(struct list_head *head)

fs/nfs/pagelist.c void nfs_release_request(struct nfs_page *req) · line 636

Quoted 5 lines

fs/nfs/pagelist.c +5 -0

+{
+	struct nfs_page *req;
+
+	while (!list_empty(head)) {
+		req = nfs_list_entry(head->next);

req could/should be local here. Or you switch to list_first_or_null, which some folks prefer.

include/linux/nfs_page.h extern struct nfs_page *nfs_page_create_from_folio(struct nfs_open_context *ctx, · line 140

Quoted 2 lines

include/linux/nfs_page.h +2 -0

+extern void nfs_release_request(struct nfs_page *req);
+extern void nfs_release_request_list(struct list_head *head);

Please drop the superflous externs for new code.

Introduce nfs_direct_extract_pages() in direct.c to centralize page extraction and request creation for the Direct I/O path. The helper manages extraction from the iters and builds a list of nfs_page requests

Refactor nfs_direct_read_schedule_iovec() and nfs_direct_write_schedule_iovec() to utilize the new helper, unifying the extraction logic on both paths.

Signed-off-by Pranjal Shrivastava <[email protected]>

---
 fs/nfs/direct.c | 127 ++++++++++++++++++++++++------------------------
 1 file changed, 64 insertions(+), 63 deletions(-)

fs/nfs/direct.c +64 -64

index b9ac0a67693c..d31e4720ffff 100644
@@ -178,6 +178,50 @@ static void nfs_direct_release_pages(struct page **pages, unsigned int npages,
        }
 }
 
+static ssize_t nfs_direct_extract_pages(struct nfs_direct_req *dreq,
+                                        struct iov_iter *iter,
+                                        size_t size, loff_t *pos,
+                                        struct list_head *list)
+{
+       bool pinned = iov_iter_extract_will_pin(iter);
+       struct page **pagevec = NULL;
+       ssize_t result, bytes = 0;
+       unsigned int npages, i;
+       size_t pgbase;
+
+       result = iov_iter_extract_pages(iter, &pagevec, size, ~0U, 0, &pgbase);
+       if (result <= 0)
+               return result;
+
+       npages = (result + pgbase + PAGE_SIZE - 1) >> PAGE_SHIFT;
+       for (i = 0; i < npages; i++) {
+               struct nfs_page *req;
+               unsigned int req_len = min_t(size_t, result - bytes, PAGE_SIZE - pgbase);
+
+               req = nfs_page_create_from_page(dreq->ctx, pagevec[i],
+                                               pinned, pgbase, *pos,
+                                               req_len);
+               if (IS_ERR(req)) {
+                       if (!bytes)
+                               bytes = PTR_ERR(req);
+                       break;
+               }
+
+               list_add_tail(&req->wb_list, list);
+               pgbase = 0;
+               bytes += req_len;
+               *pos += req_len;
+       }
+
+       if (i < npages) {
+               iov_iter_revert(iter, result - bytes);
+               nfs_direct_release_pages(pagevec + i, npages - i, pinned);
+       }
+
+       kvfree(pagevec);
+       return bytes;
+}
+
 void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo,
                              struct nfs_direct_req *dreq)
 {

@@ -346,6 +390,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
        ssize_t result = -EINVAL;
        size_t requested_bytes = 0;
        size_t rsize = max_t(size_t, NFS_SERVER(inode)->rsize, PAGE_SIZE);
+       LIST_HEAD(nfs_page_list);
 
        nfs_pageio_init_read(&desc, dreq->inode, false,
                             &nfs_direct_read_completion_ops);

@@ -354,43 +399,23 @@ 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 = NULL;
-               size_t bytes;
-               size_t pgbase;
-               unsigned npages, i;
-               bool pinned = iov_iter_extract_will_pin(iter);
-
-               result = iov_iter_extract_pages(iter, &pagevec,
-                                               rsize, ~0U, 0, &pgbase);
+               result = nfs_direct_extract_pages(dreq, iter, rsize, &pos, &nfs_page_list);
                if (result < 0)
                        break;
 
-               bytes = result;
-               npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE;
-               for (i = 0; i < npages; i++) {
-                       struct nfs_page *req;
-                       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],
-                                                       pinned, pgbase, pos,
-                                                       req_len);
-                       if (IS_ERR(req)) {
-                               result = PTR_ERR(req);
-                               break;
-                       }
+               while (!list_empty(&nfs_page_list)) {
+                       struct nfs_page *req = nfs_list_entry(nfs_page_list.next);
+                       size_t req_len = req->wb_bytes;
+
+                       nfs_list_remove_request(req);
                        if (!nfs_pageio_add_request(&desc, req)) {
                                result = desc.pg_error;
                                nfs_release_request(req);
+                               nfs_release_request_list(&nfs_page_list);
                                break;
                        }
-                       pgbase = 0;
-                       bytes -= req_len;
                        requested_bytes += req_len;
-                       pos += req_len;
                }
-               if (i < npages)
-                       nfs_direct_release_pages(pagevec + i, npages - i, pinned);
-               kvfree(pagevec);
                if (result < 0)
                        break;
        }

@@ -881,6 +906,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
        ssize_t result = 0;
        size_t requested_bytes = 0;
        size_t wsize = max_t(size_t, NFS_SERVER(inode)->wsize, PAGE_SIZE);
+       LIST_HEAD(nfs_page_list);
        bool defer = false;
 
        trace_nfs_direct_write_schedule_iovec(dreq);

@@ -893,55 +919,32 @@ 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 = NULL;
-               size_t bytes;
-               size_t pgbase;
-               unsigned npages, i;
-               bool pinned = iov_iter_extract_will_pin(iter);
-
-               result = iov_iter_extract_pages(iter, &pagevec,
-                                               wsize, ~0U, 0, &pgbase);
+               result = nfs_direct_extract_pages(dreq, iter, wsize, &pos, &nfs_page_list);
                if (result < 0)
                        break;
 
-               bytes = result;
-               npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE;
-               for (i = 0; i < npages; i++) {
-                       struct nfs_page *req;
-                       unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase);
-
-                       req = nfs_page_create_from_page(dreq->ctx, pagevec[i],
-                                                       pinned, pgbase, pos,
-                                                       req_len);
-                       if (IS_ERR(req)) {
-                               result = PTR_ERR(req);
-                               break;
-                       }
-
-                       if (desc.pg_error < 0) {
-                               nfs_free_request(req);
-                               result = desc.pg_error;
-                               break;
-                       }
-
-                       pgbase = 0;
-                       bytes -= req_len;
-                       requested_bytes += req_len;
-                       pos += req_len;
+               while (!list_empty(&nfs_page_list)) {
+                       struct nfs_page *req = nfs_list_entry(nfs_page_list.next);
+                       size_t req_len = req->wb_bytes;
 
+                       nfs_list_remove_request(req);
                        if (defer) {
                                nfs_mark_request_commit(req, NULL, &cinfo, 0);
+                               requested_bytes += req_len;
                                continue;
                        }
 
                        nfs_lock_request(req);
-                       if (nfs_pageio_add_request(&desc, req))
+                       if (nfs_pageio_add_request(&desc, req)) {
+                               requested_bytes += req_len;
                                continue;
+                       }
 
                        /* Exit on hard errors */
                        if (desc.pg_error < 0 && desc.pg_error != -EAGAIN) {
                                result = desc.pg_error;
                                nfs_unlock_and_release_request(req);
+                               nfs_release_request_list(&nfs_page_list);
                                break;
                        }
 

@@ -952,12 +955,10 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
                        spin_unlock(&dreq->lock);
                        nfs_unlock_request(req);
                        nfs_mark_request_commit(req, NULL, &cinfo, 0);
+                       requested_bytes += req_len;
                        desc.pg_error = 0;
                        defer = true;
                }
-               if (i < npages)
-                       nfs_direct_release_pages(pagevec + i, npages - i, pinned);
-               kvfree(pagevec);
                if (result < 0)
                        break;
        }
--

2.55.0.229.g6434b31f56-goog

Introduce nfs_direct_extract_pages() in direct.c to centralize page extraction and request creation for the Direct I/O path. The helper manages extraction from the iters and builds a list of nfs_page requests

Refactor nfs_direct_read_schedule_iovec() and nfs_direct_write_schedule_iovec() to utilize the new helper, unifying the extraction logic on both paths.

Signed-off-by Pranjal Shrivastava <[email protected]>

---
 fs/nfs/direct.c | 127 ++++++++++++++++++++++++---------------------- --

 1 file changed, 64 insertions(+), 63 deletions(-)

fs/nfs/direct.c +0 -0

index b9ac0a67693c..d31e4720ffff 100644
@@ -178,6 +178,50 @@ static void nfs_direct_release_pages(struct page
 **pages, unsigned int npages,
  	}
  }

fs/nfs/direct.c +12 -0

+static ssize_t nfs_direct_extract_pages(struct nfs_direct_req *dreq,
+					 struct iov_iter *iter,
+					 size_t size, loff_t *pos,
+					 struct list_head *list)
+{
+	bool pinned = iov_iter_extract_will_pin(iter);
+	struct page **pagevec = NULL;
+	ssize_t result, bytes = 0;
+	unsigned int npages, i;
+	size_t pgbase;
+
+	result = iov_iter_extract_pages(iter, &pagevec, size, ~0U,

0, &pgbase);

fs/nfs/direct.c +7 -0

+	if (result <= 0)
+		return result;
+
+	npages = (result + pgbase + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	for (i = 0; i < npages; i++) {
+		struct nfs_page *req;
+		unsigned int req_len = min_t(size_t, result - bytes,

PAGE_SIZE - pgbase);

fs/nfs/direct.c +2 -0

+
+		req = nfs_page_create_from_page(dreq->ctx,

pagevec[i],

fs/nfs/direct.c +1 -0

+						pinned, pgbase,

*pos,

fs/nfs/direct.c +5 -0

+						req_len);
+		if (IS_ERR(req)) {
+			if (!bytes)
+				bytes = PTR_ERR(req);
+			break;

fs/nfs/direct.c +1 -0

+		nfs_direct_release_pages(pagevec + i, npages - i,

pinned);

fs/nfs/direct.c +6 -0

+	}
+
+	kvfree(pagevec);
+	return bytes;
+}
+

 void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo, struct nfs_direct_req *dreq) {

fs/nfs/direct.c +1 -0

@@ -346,6 +390,7 @@ static ssize_t
 nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
  	ssize_t result = -EINVAL;
  	size_t requested_bytes = 0;
  	size_t rsize = max_t(size_t, NFS_SERVER(inode)->rsize,
 PAGE_SIZE);
+	LIST_HEAD(nfs_page_list);

  nfs_pageio_init_read(&desc, dreq->inode, false, &nfs_direct_read_completion_ops);

fs/nfs/direct.c +0 -0

@@ -354,43 +399,23 @@ static ssize_t
 nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
  	inode_dio_begin(inode);

  while (iov_iter_count(iter)) {

fs/nfs/direct.c +0 -8

-		struct page **pagevec = NULL;
-		size_t bytes;
-		size_t pgbase;
-		unsigned npages, i;
-		bool pinned = iov_iter_extract_will_pin(iter);
-
-		result = iov_iter_extract_pages(iter, &pagevec,
-						rsize, ~0U, 0,

&pgbase);

fs/nfs/direct.c +1 -0

+		result = nfs_direct_extract_pages(dreq, iter, rsize,

&pos, &nfs_page_list);
  if (result < 0)
  break;

fs/nfs/direct.c +0 -2

-		bytes = result;
-		npages = (result + pgbase + PAGE_SIZE - 1) /

PAGE_SIZE;

fs/nfs/direct.c +0 -3

-		for (i = 0; i < npages; i++) {
-			struct nfs_page *req;
-			unsigned int req_len = min_t(size_t, bytes,

PAGE_SIZE - pgbase);

fs/nfs/direct.c +0 -1

-			/* XXX do we need to do the eof zeroing

found in async_filler? */

fs/nfs/direct.c +0 -1

-			req = nfs_page_create_from_page(dreq->ctx,

pagevec[i],

fs/nfs/direct.c +0 -1

-							pinned,

pgbase, pos,

fs/nfs/direct.c +2 -5

-							req_len);
-			if (IS_ERR(req)) {
-				result = PTR_ERR(req);
-				break;
-			}
+		while (!list_empty(&nfs_page_list)) {
+			struct nfs_page *req =

nfs_list_entry(nfs_page_list.next);

fs/nfs/direct.c +3 -0

+			size_t req_len = req->wb_bytes;
+
+			nfs_list_remove_request(req);

  if (!nfs_pageio_add_request(&desc, req)) { result = desc.pg_error; nfs_release_request(req);

fs/nfs/direct.c +1 -0

+				nfs_release_request_list(&nfs_page_l

ist);
  break;
  }

fs/nfs/direct.c +0 -2

-			pgbase = 0;
-			bytes -= req_len;

  requested_bytes += req_len;

fs/nfs/direct.c +0 -1

-			pos += req_len;

  }

fs/nfs/direct.c +0 -4

-		if (i < npages)
-			nfs_direct_release_pages(pagevec + i, npages
- i, pinned);
-		kvfree(pagevec);

  if (result < 0)
  break;
  }

fs/nfs/direct.c +1 -0

@@ -881,6 +906,7 @@ static ssize_t
 nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
  	ssize_t result = 0;
  	size_t requested_bytes = 0;
  	size_t wsize = max_t(size_t, NFS_SERVER(inode)->wsize,
 PAGE_SIZE);
+	LIST_HEAD(nfs_page_list);
  	bool defer = false;

trace_nfs_direct_write_schedule_iovec(dreq);

fs/nfs/direct.c +0 -0

@@ -893,55 +919,32 @@ 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)) {

fs/nfs/direct.c +0 -8

-		struct page **pagevec = NULL;
-		size_t bytes;
-		size_t pgbase;
-		unsigned npages, i;
-		bool pinned = iov_iter_extract_will_pin(iter);
-
-		result = iov_iter_extract_pages(iter, &pagevec,
-						wsize, ~0U, 0,

&pgbase);

fs/nfs/direct.c +1 -0

+		result = nfs_direct_extract_pages(dreq, iter, wsize,

&pos, &nfs_page_list);
  if (result < 0)
  break;

fs/nfs/direct.c +0 -2

-		bytes = result;
-		npages = (result + pgbase + PAGE_SIZE - 1) /

PAGE_SIZE;

fs/nfs/direct.c +0 -3

-		for (i = 0; i < npages; i++) {
-			struct nfs_page *req;
-			unsigned int req_len = min_t(size_t, bytes,

PAGE_SIZE - pgbase);

fs/nfs/direct.c +0 -2

-
-			req = nfs_page_create_from_page(dreq->ctx,

pagevec[i],

fs/nfs/direct.c +0 -1

-							pinned,

pgbase, pos,

fs/nfs/direct.c +2 -16

-							req_len);
-			if (IS_ERR(req)) {
-				result = PTR_ERR(req);
-				break;
-			}
-
-			if (desc.pg_error < 0) {
-				nfs_free_request(req);
-				result = desc.pg_error;
-				break;
-			}
-
-			pgbase = 0;
-			bytes -= req_len;
-			requested_bytes += req_len;
-			pos += req_len;
+		while (!list_empty(&nfs_page_list)) {
+			struct nfs_page *req =

nfs_list_entry(nfs_page_list.next);

fs/nfs/direct.c +1 -0

+			size_t req_len = req->wb_bytes;

fs/nfs/direct.c +1 -0

+			nfs_list_remove_request(req);

  if (defer) { nfs_mark_request_commit(req, NULL, &cinfo, 0);

fs/nfs/direct.c +1 -0

+				requested_bytes += req_len;

  continue;
  }

  nfs_lock_request(req);

fs/nfs/direct.c +2 -1

-			if (nfs_pageio_add_request(&desc, req))
+			if (nfs_pageio_add_request(&desc, req)) {
+				requested_bytes += req_len;

  continue;

fs/nfs/direct.c +1 -0

+			}

  /* Exit on hard errors */
  if (desc.pg_error < 0 && desc.pg_error != - EAGAIN) {
  result = desc.pg_error; nfs_unlock_and_release_request(req);

fs/nfs/direct.c +1 -0

+				nfs_release_request_list(&nfs_page_l

ist);
  break;
  }

fs/nfs/direct.c +1 -4

@@ -952,12 +955,10 @@ static ssize_t
 nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
  			spin_unlock(&dreq->lock);
  			nfs_unlock_request(req);
  			nfs_mark_request_commit(req, NULL, &cinfo,
 0);
+			requested_bytes += req_len;
  			desc.pg_error = 0;
  			defer = true;
  		}
-		if (i < npages)
-			nfs_direct_release_pages(pagevec + i, npages
- i, pinned);
-		kvfree(pagevec);

  if (result < 0)
  break;
  }

Quoted 59 lines

Introduce nfs_direct_extract_pages() in direct.c to centralize page extraction and request creation for the Direct I/O path. The helper manages extraction from the iters and builds a list of nfs_page requests

Refactor nfs_direct_read_schedule_iovec() and nfs_direct_write_schedule_iovec() to utilize the new helper, unifying the extraction logic on both paths.

Signed-off-by Pranjal Shrivastava <[email protected]>

---
 fs/nfs/direct.c | 127 ++++++++++++++++++++++++---------------------- --

 1 file changed, 64 insertions(+), 63 deletions(-)

fs/nfs/direct.c +0 -0

index b9ac0a67693c..d31e4720ffff 100644
@@ -178,6 +178,50 @@ static void nfs_direct_release_pages(struct page
 **pages, unsigned int npages,
  	}
  }

fs/nfs/direct.c +12 -0

+static ssize_t nfs_direct_extract_pages(struct nfs_direct_req *dreq,
+					 struct iov_iter *iter,
+					 size_t size, loff_t *pos,
+					 struct list_head *list)
+{
+	bool pinned = iov_iter_extract_will_pin(iter);
+	struct page **pagevec = NULL;
+	ssize_t result, bytes = 0;
+	unsigned int npages, i;
+	size_t pgbase;
+
+	result = iov_iter_extract_pages(iter, &pagevec, size, ~0U,

0, &pgbase);

fs/nfs/direct.c +7 -0

+	if (result <= 0)
+		return result;
+
+	npages = (result + pgbase + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	for (i = 0; i < npages; i++) {
+		struct nfs_page *req;
+		unsigned int req_len = min_t(size_t, result - bytes,

PAGE_SIZE - pgbase);

fs/nfs/direct.c +2 -0

+
+		req = nfs_page_create_from_page(dreq->ctx,

pagevec[i],

fs/nfs/direct.c +1 -0

+						pinned, pgbase,

*pos,

fs/nfs/direct.c +9 -0

+						req_len);
+		if (IS_ERR(req)) {
+			if (!bytes)
+				bytes = PTR_ERR(req);
+			break;
+		}
+
+		list_add_tail(&req->wb_list, list);
+		pgbase = 0;

fs/nfs/direct.c static void nfs_direct_release_pages(struct page **pages, unsigned int npages, · line 217

Quoted 6 lines

fs/nfs/direct.c +6 -0

+		bytes += req_len;
+		*pos += req_len;
+	}
+
+	if (i < npages) {
+		iov_iter_revert(iter, result - bytes);

Oopsable if bytes == PTR_ERR(req)

Quoted 2 lines

fs/nfs/direct.c +1 -0

+		nfs_direct_release_pages(pagevec + i, npages - i,

pinned);

See what happens above with swap over NFS (which sets pinned = false).