Merge tag '6.3-rc-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs client updates from Steve French:
 "The largest subset of this is from David Howells et al: making the
  cifs/smb3 driver pass iov_iters down to the lowest layers, directly to
  the network transport rather than passing lists of pages around,
  helping multiple areas:

   - Pin user pages, thereby fixing the race between concurrent DIO read
     and fork, where the pages containing the DIO read buffer may end up
     belonging to the child process and not the parent - with the result
     that the parent might not see the retrieved data.

   - cifs shouldn't take refs on pages extracted from non-user-backed
     iterators (eg. KVEC). With these changes, cifs will apply the
     appropriate cleanup.

   - Making it easier to transition to using folios in cifs rather than
     pages by dealing with them through BVEC and XARRAY iterators.

   - Allowing cifs to use the new splice function

  The remainder are:

   - fixes for stable, including various fixes for uninitialized memory,
     wrong length field causing mount issue to very old servers,
     important directory lease fixes and reconnect fixes

   - cleanups (unused code removal, change one element array usage, and
     a change form strtobool to kstrtobool, and Kconfig cleanups)

   - SMBDIRECT (RDMA) fixes including iov_iter integration and UAF fixes

   - reconnect fixes

   - multichannel fixes, including improving channel allocation (to
     least used channel)

   - remove the last use of lock_page_killable by moving to
     folio_lock_killable"

* tag '6.3-rc-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: (46 commits)
  update internal module version number for cifs.ko
  cifs: update ip_addr for ses only for primary chan setup
  cifs: use tcon allocation functions even for dummy tcon
  cifs: use the least loaded channel for sending requests
  cifs: DIO to/from KVEC-type iterators should now work
  cifs: Remove unused code
  cifs: Build the RDMA SGE list directly from an iterator
  cifs: Change the I/O paths to use an iterator rather than a page list
  cifs: Add a function to read into an iter from a socket
  cifs: Add some helper functions
  cifs: Add a function to Hash the contents of an iterator
  cifs: Add a function to build an RDMA SGE list from an iterator
  netfs: Add a function to extract an iterator into a scatterlist
  netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator
  cifs: Implement splice_read to pass down ITER_BVEC not ITER_PIPE
  splice: Export filemap/direct_splice_read()
  iov_iter: Add a function to extract a page list from an iterator
  iov_iter: Define flags to qualify page extraction.
  splice: Add a func to do a splice from an O_DIRECT file without ITER_PIPE
  splice: Add a func to do a splice from a buffered file without ITER_PIPE
  ...

1 files changed, 33 insertions, 2 deletions

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 73b1d5d1e4f1..27e3fd942960 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -13,6 +13,8 @@
 struct page;
 struct pipe_inode_info;
 
+typedef unsigned int __bitwise iov_iter_extraction_t;
+
 struct kvec {
 	void *iov_base; /* and that should *never* hold a userland pointer */
 	size_t iov_len;
@@ -252,12 +254,12 @@ void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *
 		     loff_t start, size_t count);
 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
 		size_t maxsize, unsigned maxpages, size_t *start,
-		unsigned gup_flags);
+		iov_iter_extraction_t extraction_flags);
 ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
 			size_t maxsize, unsigned maxpages, size_t *start);
 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 		struct page ***pages, size_t maxsize, size_t *start,
-		unsigned gup_flags);
+		iov_iter_extraction_t extraction_flags);
 ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages,
 			size_t maxsize, size_t *start);
 int iov_iter_npages(const struct iov_iter *i, int maxpages);
@@ -360,5 +362,34 @@ static inline void iov_iter_ubuf(struct iov_iter *i, unsigned int direction,
 		.count = count
 	};
 }
+/* Flags for iov_iter_get/extract_pages*() */
+/* Allow P2PDMA on the extracted pages */
+#define ITER_ALLOW_P2PDMA	((__force iov_iter_extraction_t)0x01)
+
+ssize_t iov_iter_extract_pages(struct iov_iter *i, struct page ***pages,
+			       size_t maxsize, unsigned int maxpages,
+			       iov_iter_extraction_t extraction_flags,
+			       size_t *offset0);
+
+/**
+ * iov_iter_extract_will_pin - Indicate how pages from the iterator will be retained
+ * @iter: The iterator
+ *
+ * Examine the iterator and indicate by returning true or false as to how, if
+ * at all, pages extracted from the iterator will be retained by the extraction
+ * function.
+ *
+ * %true indicates that the pages will have a pin placed in them that the
+ * caller must unpin.  This is must be done for DMA/async DIO to force fork()
+ * to forcibly copy a page for the child (the parent must retain the original
+ * page).
+ *
+ * %false indicates that no measures are taken and that it's up to the caller
+ * to retain the pages.
+ */
+static inline bool iov_iter_extract_will_pin(const struct iov_iter *iter)
+{
+	return user_backed_iter(iter);
+}
 
 #endif