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@xxxxxxxxxx>
cc: Jeff Layton <jlayton@xxxxxxxxxx>
cc: Steve French <sfrench@xxxxxxxxx>
cc: Shyam Prasad N <nspmangalore@xxxxxxxxx>
cc: Rohith Surabattula <rohiths.msft@xxxxxxxxx>
cc: Jens Axboe <axboe@xxxxxxxxx>
cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
cc: Eric Dumazet <edumazet@xxxxxxxxxx>
cc: Jakub Kicinski <kuba@xxxxxxxxxx>
cc: Paolo Abeni <pabeni@xxxxxxxxxx>
cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
cc: linux-crypto@xxxxxxxxxxxxxxx
cc: linux-cachefs@xxxxxxxxxx
cc: linux-cifs@xxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
cc: netdev@xxxxxxxxxxxxxxx
---
fs/netfs/iterator.c | 267 -----------------------------------------
include/linux/netfs.h | 4 -
include/linux/uio.h | 5 +
lib/scatterlist.c | 269 ++++++++++++++++++++++++++++++++++++++++++
4 files changed, 274 insertions(+), 271 deletions(-)
diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c
index 9f09dc30ceb6..2ff07ba655a0 100644
--- 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);
-
-/*
- * 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 55e201c3a841..b11a84f6c32b 100644
--- 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);
-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
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 044c1d8c230c..0ccb983cf645 100644
--- 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);
}
+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
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 8d7519a8f308..e97d7060329e 100644
--- 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/bvec.h>
+#include <linux/uio.h>
/**
* 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);
+
+/*
+ * 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);
