Move netfs_extract_iter_to_sg() to lib/scatterlist.c

Move netfs_extract_iter_to_sg() to lib/scatterlist.c as it's going to be
used by more than just network filesystems (AF_ALG, for example).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-crypto@vger.kernel.org
cc: linux-cachefs@redhat.com
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: netdev@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c
index 9f09dc3..2ff07ba 100644 (file)
--- a/fs/netfs/iterator.c
+++ b/fs/netfs/iterator.c
@@ -101,270 +101,3 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
        return npages;
 }
 EXPORT_SYMBOL_GPL(netfs_extract_user_iter);
        return npages;
 }
 EXPORT_SYMBOL_GPL(netfs_extract_user_iter);

-
-/*
- * Extract and pin a list of up to sg_max pages from UBUF- or IOVEC-class
- * iterators, and add them to the scatterlist.
- */
-static ssize_t extract_user_to_sg(struct iov_iter *iter,
-                                 ssize_t maxsize,
-                                 struct sg_table *sgtable,
-                                 unsigned int sg_max,
-                                 iov_iter_extraction_t extraction_flags)
-{
-       struct scatterlist *sg = sgtable->sgl + sgtable->nents;
-       struct page **pages;
-       unsigned int npages;
-       ssize_t ret = 0, res;
-       size_t len, off;
-
-       /* We decant the page list into the tail of the scatterlist */
-       pages = (void *)sgtable->sgl +
-               array_size(sg_max, sizeof(struct scatterlist));
-       pages -= sg_max;
-
-       do {
-               res = iov_iter_extract_pages(iter, &pages, maxsize, sg_max,
-                                            extraction_flags, &off);
-               if (res < 0)
-                       goto failed;
-
-               len = res;
-               maxsize -= len;
-               ret += len;
-               npages = DIV_ROUND_UP(off + len, PAGE_SIZE);
-               sg_max -= npages;
-
-               for (; npages > 0; npages--) {
-                       struct page *page = *pages;
-                       size_t seg = min_t(size_t, PAGE_SIZE - off, len);
-
-                       *pages++ = NULL;
-                       sg_set_page(sg, page, seg, off);
-                       sgtable->nents++;
-                       sg++;
-                       len -= seg;
-                       off = 0;
-               }
-       } while (maxsize > 0 && sg_max > 0);
-
-       return ret;
-
-failed:
-       while (sgtable->nents > sgtable->orig_nents)
-               put_page(sg_page(&sgtable->sgl[--sgtable->nents]));
-       return res;
-}
-
-/*
- * Extract up to sg_max pages from a BVEC-type iterator and add them to the
- * scatterlist.  The pages are not pinned.
- */
-static ssize_t extract_bvec_to_sg(struct iov_iter *iter,
-                                 ssize_t maxsize,
-                                 struct sg_table *sgtable,
-                                 unsigned int sg_max,
-                                 iov_iter_extraction_t extraction_flags)
-{
-       const struct bio_vec *bv = iter->bvec;
-       struct scatterlist *sg = sgtable->sgl + sgtable->nents;
-       unsigned long start = iter->iov_offset;
-       unsigned int i;
-       ssize_t ret = 0;
-
-       for (i = 0; i < iter->nr_segs; i++) {
-               size_t off, len;
-
-               len = bv[i].bv_len;
-               if (start >= len) {
-                       start -= len;
-                       continue;
-               }
-
-               len = min_t(size_t, maxsize, len - start);
-               off = bv[i].bv_offset + start;
-
-               sg_set_page(sg, bv[i].bv_page, len, off);
-               sgtable->nents++;
-               sg++;
-               sg_max--;
-
-               ret += len;
-               maxsize -= len;
-               if (maxsize <= 0 || sg_max == 0)
-                       break;
-               start = 0;
-       }
-
-       if (ret > 0)
-               iov_iter_advance(iter, ret);
-       return ret;
-}
-
-/*
- * Extract up to sg_max pages from a KVEC-type iterator and add them to the
- * scatterlist.  This can deal with vmalloc'd buffers as well as kmalloc'd or
- * static buffers.  The pages are not pinned.
- */
-static ssize_t extract_kvec_to_sg(struct iov_iter *iter,
-                                 ssize_t maxsize,
-                                 struct sg_table *sgtable,
-                                 unsigned int sg_max,
-                                 iov_iter_extraction_t extraction_flags)
-{
-       const struct kvec *kv = iter->kvec;
-       struct scatterlist *sg = sgtable->sgl + sgtable->nents;
-       unsigned long start = iter->iov_offset;
-       unsigned int i;
-       ssize_t ret = 0;
-
-       for (i = 0; i < iter->nr_segs; i++) {
-               struct page *page;
-               unsigned long kaddr;
-               size_t off, len, seg;
-
-               len = kv[i].iov_len;
-               if (start >= len) {
-                       start -= len;
-                       continue;
-               }
-
-               kaddr = (unsigned long)kv[i].iov_base + start;
-               off = kaddr & ~PAGE_MASK;
-               len = min_t(size_t, maxsize, len - start);
-               kaddr &= PAGE_MASK;
-
-               maxsize -= len;
-               ret += len;
-               do {
-                       seg = min_t(size_t, len, PAGE_SIZE - off);
-                       if (is_vmalloc_or_module_addr((void *)kaddr))
-                               page = vmalloc_to_page((void *)kaddr);
-                       else
-                               page = virt_to_page(kaddr);
-
-                       sg_set_page(sg, page, len, off);
-                       sgtable->nents++;
-                       sg++;
-                       sg_max--;
-
-                       len -= seg;
-                       kaddr += PAGE_SIZE;
-                       off = 0;
-               } while (len > 0 && sg_max > 0);
-
-               if (maxsize <= 0 || sg_max == 0)
-                       break;
-               start = 0;
-       }
-
-       if (ret > 0)
-               iov_iter_advance(iter, ret);
-       return ret;
-}
-
-/*
- * Extract up to sg_max folios from an XARRAY-type iterator and add them to
- * the scatterlist.  The pages are not pinned.
- */
-static ssize_t extract_xarray_to_sg(struct iov_iter *iter,
-                                   ssize_t maxsize,
-                                   struct sg_table *sgtable,
-                                   unsigned int sg_max,
-                                   iov_iter_extraction_t extraction_flags)
-{
-       struct scatterlist *sg = sgtable->sgl + sgtable->nents;
-       struct xarray *xa = iter->xarray;
-       struct folio *folio;
-       loff_t start = iter->xarray_start + iter->iov_offset;
-       pgoff_t index = start / PAGE_SIZE;
-       ssize_t ret = 0;
-       size_t offset, len;
-       XA_STATE(xas, xa, index);
-
-       rcu_read_lock();
-
-       xas_for_each(&xas, folio, ULONG_MAX) {
-               if (xas_retry(&xas, folio))
-                       continue;
-               if (WARN_ON(xa_is_value(folio)))
-                       break;
-               if (WARN_ON(folio_test_hugetlb(folio)))
-                       break;
-
-               offset = offset_in_folio(folio, start);
-               len = min_t(size_t, maxsize, folio_size(folio) - offset);
-
-               sg_set_page(sg, folio_page(folio, 0), len, offset);
-               sgtable->nents++;
-               sg++;
-               sg_max--;
-
-               maxsize -= len;
-               ret += len;
-               if (maxsize <= 0 || sg_max == 0)
-                       break;
-       }
-
-       rcu_read_unlock();
-       if (ret > 0)
-               iov_iter_advance(iter, ret);
-       return ret;
-}
-
-/**
- * extract_iter_to_sg - Extract pages from an iterator and add to an sglist
- * @iter: The iterator to extract from
- * @maxsize: The amount of iterator to copy
- * @sgtable: The scatterlist table to fill in
- * @sg_max: Maximum number of elements in @sgtable that may be filled
- * @extraction_flags: Flags to qualify the request
- *
- * Extract the page fragments from the given amount of the source iterator and
- * add them to a scatterlist that refers to all of those bits, to a maximum
- * addition of @sg_max elements.
- *
- * The pages referred to by UBUF- and IOVEC-type iterators are extracted and
- * pinned; BVEC-, KVEC- and XARRAY-type are extracted but aren't pinned; PIPE-
- * and DISCARD-type are not supported.
- *
- * No end mark is placed on the scatterlist; that's left to the caller.
- *
- * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA
- * be allowed on the pages extracted.
- *
- * If successful, @sgtable->nents is updated to include the number of elements
- * added and the number of bytes added is returned.  @sgtable->orig_nents is
- * left unaltered.
- *
- * The iov_iter_extract_mode() function should be used to query how cleanup
- * should be performed.
- */
-ssize_t extract_iter_to_sg(struct iov_iter *iter, size_t maxsize,
-                          struct sg_table *sgtable, unsigned int sg_max,
-                          iov_iter_extraction_t extraction_flags)
-{
-       if (maxsize == 0)
-               return 0;
-
-       switch (iov_iter_type(iter)) {
-       case ITER_UBUF:
-       case ITER_IOVEC:
-               return extract_user_to_sg(iter, maxsize, sgtable, sg_max,
-                                         extraction_flags);
-       case ITER_BVEC:
-               return extract_bvec_to_sg(iter, maxsize, sgtable, sg_max,
-                                         extraction_flags);
-       case ITER_KVEC:
-               return extract_kvec_to_sg(iter, maxsize, sgtable, sg_max,
-                                         extraction_flags);
-       case ITER_XARRAY:
-               return extract_xarray_to_sg(iter, maxsize, sgtable, sg_max,
-                                           extraction_flags);
-       default:
-               pr_err("%s(%u) unsupported\n", __func__, iov_iter_type(iter));
-               WARN_ON_ONCE(1);
-               return -EIO;
-       }
-}
-EXPORT_SYMBOL_GPL(extract_iter_to_sg);

diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 55e201c..b11a84f 100644 (file)
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -300,10 +300,6 @@ void netfs_stats_show(struct seq_file *);
 ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
                                struct iov_iter *new,
                                iov_iter_extraction_t extraction_flags);
 ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
                                struct iov_iter *new,
                                iov_iter_extraction_t extraction_flags);

-struct sg_table;
-ssize_t extract_iter_to_sg(struct iov_iter *iter, size_t len,
-                          struct sg_table *sgtable, unsigned int sg_max,
-                          iov_iter_extraction_t extraction_flags);

 
 /**
  * netfs_inode - Get the netfs inode context from the inode
 
 /**
  * netfs_inode - Get the netfs inode context from the inode

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 044c1d8..0ccb983 100644 (file)
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -433,4 +433,9 @@ static inline bool iov_iter_extract_will_pin(const struct iov_iter *iter)
        return user_backed_iter(iter);
 }
 
        return user_backed_iter(iter);
 }
 

+struct sg_table;
+ssize_t extract_iter_to_sg(struct iov_iter *iter, size_t len,
+                          struct sg_table *sgtable, unsigned int sg_max,
+                          iov_iter_extraction_t extraction_flags);
+

 #endif
 #endif

diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 8d7519a..e97d706 100644 (file)
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -9,6 +9,8 @@
 #include <linux/scatterlist.h>
 #include <linux/highmem.h>
 #include <linux/kmemleak.h>
 #include <linux/scatterlist.h>
 #include <linux/highmem.h>
 #include <linux/kmemleak.h>

+#include <linux/bvec.h>
+#include <linux/uio.h>

 
 /**
  * sg_next - return the next scatterlist entry in a list
 
 /**
  * sg_next - return the next scatterlist entry in a list


@@ -1095,3 +1097,270 @@ size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents,
        return offset;
 }
 EXPORT_SYMBOL(sg_zero_buffer);
        return offset;
 }
 EXPORT_SYMBOL(sg_zero_buffer);

+
+/*
+ * Extract and pin a list of up to sg_max pages from UBUF- or IOVEC-class
+ * iterators, and add them to the scatterlist.
+ */
+static ssize_t extract_user_to_sg(struct iov_iter *iter,
+                                 ssize_t maxsize,
+                                 struct sg_table *sgtable,
+                                 unsigned int sg_max,
+                                 iov_iter_extraction_t extraction_flags)
+{
+       struct scatterlist *sg = sgtable->sgl + sgtable->nents;
+       struct page **pages;
+       unsigned int npages;
+       ssize_t ret = 0, res;
+       size_t len, off;
+
+       /* We decant the page list into the tail of the scatterlist */
+       pages = (void *)sgtable->sgl +
+               array_size(sg_max, sizeof(struct scatterlist));
+       pages -= sg_max;
+
+       do {
+               res = iov_iter_extract_pages(iter, &pages, maxsize, sg_max,
+                                            extraction_flags, &off);
+               if (res < 0)
+                       goto failed;
+
+               len = res;
+               maxsize -= len;
+               ret += len;
+               npages = DIV_ROUND_UP(off + len, PAGE_SIZE);
+               sg_max -= npages;
+
+               for (; npages > 0; npages--) {
+                       struct page *page = *pages;
+                       size_t seg = min_t(size_t, PAGE_SIZE - off, len);
+
+                       *pages++ = NULL;
+                       sg_set_page(sg, page, seg, off);
+                       sgtable->nents++;
+                       sg++;
+                       len -= seg;
+                       off = 0;
+               }
+       } while (maxsize > 0 && sg_max > 0);
+
+       return ret;
+
+failed:
+       while (sgtable->nents > sgtable->orig_nents)
+               put_page(sg_page(&sgtable->sgl[--sgtable->nents]));
+       return res;
+}
+
+/*
+ * Extract up to sg_max pages from a BVEC-type iterator and add them to the
+ * scatterlist.  The pages are not pinned.
+ */
+static ssize_t extract_bvec_to_sg(struct iov_iter *iter,
+                                 ssize_t maxsize,
+                                 struct sg_table *sgtable,
+                                 unsigned int sg_max,
+                                 iov_iter_extraction_t extraction_flags)
+{
+       const struct bio_vec *bv = iter->bvec;
+       struct scatterlist *sg = sgtable->sgl + sgtable->nents;
+       unsigned long start = iter->iov_offset;
+       unsigned int i;
+       ssize_t ret = 0;
+
+       for (i = 0; i < iter->nr_segs; i++) {
+               size_t off, len;
+
+               len = bv[i].bv_len;
+               if (start >= len) {
+                       start -= len;
+                       continue;
+               }
+
+               len = min_t(size_t, maxsize, len - start);
+               off = bv[i].bv_offset + start;
+
+               sg_set_page(sg, bv[i].bv_page, len, off);
+               sgtable->nents++;
+               sg++;
+               sg_max--;
+
+               ret += len;
+               maxsize -= len;
+               if (maxsize <= 0 || sg_max == 0)
+                       break;
+               start = 0;
+       }
+
+       if (ret > 0)
+               iov_iter_advance(iter, ret);
+       return ret;
+}
+
+/*
+ * Extract up to sg_max pages from a KVEC-type iterator and add them to the
+ * scatterlist.  This can deal with vmalloc'd buffers as well as kmalloc'd or
+ * static buffers.  The pages are not pinned.
+ */
+static ssize_t extract_kvec_to_sg(struct iov_iter *iter,
+                                 ssize_t maxsize,
+                                 struct sg_table *sgtable,
+                                 unsigned int sg_max,
+                                 iov_iter_extraction_t extraction_flags)
+{
+       const struct kvec *kv = iter->kvec;
+       struct scatterlist *sg = sgtable->sgl + sgtable->nents;
+       unsigned long start = iter->iov_offset;
+       unsigned int i;
+       ssize_t ret = 0;
+
+       for (i = 0; i < iter->nr_segs; i++) {
+               struct page *page;
+               unsigned long kaddr;
+               size_t off, len, seg;
+
+               len = kv[i].iov_len;
+               if (start >= len) {
+                       start -= len;
+                       continue;
+               }
+
+               kaddr = (unsigned long)kv[i].iov_base + start;
+               off = kaddr & ~PAGE_MASK;
+               len = min_t(size_t, maxsize, len - start);
+               kaddr &= PAGE_MASK;
+
+               maxsize -= len;
+               ret += len;
+               do {
+                       seg = min_t(size_t, len, PAGE_SIZE - off);
+                       if (is_vmalloc_or_module_addr((void *)kaddr))
+                               page = vmalloc_to_page((void *)kaddr);
+                       else
+                               page = virt_to_page(kaddr);
+
+                       sg_set_page(sg, page, len, off);
+                       sgtable->nents++;
+                       sg++;
+                       sg_max--;
+
+                       len -= seg;
+                       kaddr += PAGE_SIZE;
+                       off = 0;
+               } while (len > 0 && sg_max > 0);
+
+               if (maxsize <= 0 || sg_max == 0)
+                       break;
+               start = 0;
+       }
+
+       if (ret > 0)
+               iov_iter_advance(iter, ret);
+       return ret;
+}
+
+/*
+ * Extract up to sg_max folios from an XARRAY-type iterator and add them to
+ * the scatterlist.  The pages are not pinned.
+ */
+static ssize_t extract_xarray_to_sg(struct iov_iter *iter,
+                                   ssize_t maxsize,
+                                   struct sg_table *sgtable,
+                                   unsigned int sg_max,
+                                   iov_iter_extraction_t extraction_flags)
+{
+       struct scatterlist *sg = sgtable->sgl + sgtable->nents;
+       struct xarray *xa = iter->xarray;
+       struct folio *folio;
+       loff_t start = iter->xarray_start + iter->iov_offset;
+       pgoff_t index = start / PAGE_SIZE;
+       ssize_t ret = 0;
+       size_t offset, len;
+       XA_STATE(xas, xa, index);
+
+       rcu_read_lock();
+
+       xas_for_each(&xas, folio, ULONG_MAX) {
+               if (xas_retry(&xas, folio))
+                       continue;
+               if (WARN_ON(xa_is_value(folio)))
+                       break;
+               if (WARN_ON(folio_test_hugetlb(folio)))
+                       break;
+
+               offset = offset_in_folio(folio, start);
+               len = min_t(size_t, maxsize, folio_size(folio) - offset);
+
+               sg_set_page(sg, folio_page(folio, 0), len, offset);
+               sgtable->nents++;
+               sg++;
+               sg_max--;
+
+               maxsize -= len;
+               ret += len;
+               if (maxsize <= 0 || sg_max == 0)
+                       break;
+       }
+
+       rcu_read_unlock();
+       if (ret > 0)
+               iov_iter_advance(iter, ret);
+       return ret;
+}
+
+/**
+ * extract_iter_to_sg - Extract pages from an iterator and add to an sglist
+ * @iter: The iterator to extract from
+ * @maxsize: The amount of iterator to copy
+ * @sgtable: The scatterlist table to fill in
+ * @sg_max: Maximum number of elements in @sgtable that may be filled
+ * @extraction_flags: Flags to qualify the request
+ *
+ * Extract the page fragments from the given amount of the source iterator and
+ * add them to a scatterlist that refers to all of those bits, to a maximum
+ * addition of @sg_max elements.
+ *
+ * The pages referred to by UBUF- and IOVEC-type iterators are extracted and
+ * pinned; BVEC-, KVEC- and XARRAY-type are extracted but aren't pinned; PIPE-
+ * and DISCARD-type are not supported.
+ *
+ * No end mark is placed on the scatterlist; that's left to the caller.
+ *
+ * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA
+ * be allowed on the pages extracted.
+ *
+ * If successful, @sgtable->nents is updated to include the number of elements
+ * added and the number of bytes added is returned.  @sgtable->orig_nents is
+ * left unaltered.
+ *
+ * The iov_iter_extract_mode() function should be used to query how cleanup
+ * should be performed.
+ */
+ssize_t extract_iter_to_sg(struct iov_iter *iter, size_t maxsize,
+                          struct sg_table *sgtable, unsigned int sg_max,
+                          iov_iter_extraction_t extraction_flags)
+{
+       if (maxsize == 0)
+               return 0;
+
+       switch (iov_iter_type(iter)) {
+       case ITER_UBUF:
+       case ITER_IOVEC:
+               return extract_user_to_sg(iter, maxsize, sgtable, sg_max,
+                                         extraction_flags);
+       case ITER_BVEC:
+               return extract_bvec_to_sg(iter, maxsize, sgtable, sg_max,
+                                         extraction_flags);
+       case ITER_KVEC:
+               return extract_kvec_to_sg(iter, maxsize, sgtable, sg_max,
+                                         extraction_flags);
+       case ITER_XARRAY:
+               return extract_xarray_to_sg(iter, maxsize, sgtable, sg_max,
+                                           extraction_flags);
+       default:
+               pr_err("%s(%u) unsupported\n", __func__, iov_iter_type(iter));
+               WARN_ON_ONCE(1);
+               return -EIO;
+       }
+}
+EXPORT_SYMBOL_GPL(extract_iter_to_sg);