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authorLinus Torvalds <torvalds@linux-foundation.org>2014-06-12 21:30:18 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-12 21:30:18 +0400
commit16b9057804c02e2d351e9c8f606e909b43cbd9e7 (patch)
treea3ac6e1d9d57a8abf4267e5ead3f2de1309335eb /mm
parent5c02c392cd2320e8d612376d6b72b6548a680923 (diff)
parentc2338f2dc7c1e9f6202f370c64ffd7f44f3d4b51 (diff)
downloadlinux-16b9057804c02e2d351e9c8f606e909b43cbd9e7.tar.xz
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro: "This the bunch that sat in -next + lock_parent() fix. This is the minimal set; there's more pending stuff. In particular, I really hope to get acct.c fixes merged this cycle - we need that to deal sanely with delayed-mntput stuff. In the next pile, hopefully - that series is fairly short and localized (kernel/acct.c, fs/super.c and fs/namespace.c). In this pile: more iov_iter work. Most of prereqs for ->splice_write with sane locking order are there and Kent's dio rewrite would also fit nicely on top of this pile" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (70 commits) lock_parent: don't step on stale ->d_parent of all-but-freed one kill generic_file_splice_write() ceph: switch to iter_file_splice_write() shmem: switch to iter_file_splice_write() nfs: switch to iter_splice_write_file() fs/splice.c: remove unneeded exports ocfs2: switch to iter_file_splice_write() ->splice_write() via ->write_iter() bio_vec-backed iov_iter optimize copy_page_{to,from}_iter() bury generic_file_aio_{read,write} lustre: get rid of messing with iovecs ceph: switch to ->write_iter() ceph_sync_direct_write: stop poking into iov_iter guts ceph_sync_read: stop poking into iov_iter guts new helper: copy_page_from_iter() fuse: switch to ->write_iter() btrfs: switch to ->write_iter() ocfs2: switch to ->write_iter() xfs: switch to ->write_iter() ...
Diffstat (limited to 'mm')
-rw-r--r--mm/filemap.c158
-rw-r--r--mm/iov_iter.c595
-rw-r--r--mm/page_io.c21
-rw-r--r--mm/process_vm_access.c10
-rw-r--r--mm/shmem.c26
-rw-r--r--mm/vmscan.c2
6 files changed, 626 insertions, 186 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 7fadf1c62838..dafb06f70a09 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1665,96 +1665,42 @@ out:
return written ? written : error;
}
-/*
- * Performs necessary checks before doing a write
- * @iov: io vector request
- * @nr_segs: number of segments in the iovec
- * @count: number of bytes to write
- * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE
- *
- * Adjust number of segments and amount of bytes to write (nr_segs should be
- * properly initialized first). Returns appropriate error code that caller
- * should return or zero in case that write should be allowed.
- */
-int generic_segment_checks(const struct iovec *iov,
- unsigned long *nr_segs, size_t *count, int access_flags)
-{
- unsigned long seg;
- size_t cnt = 0;
- for (seg = 0; seg < *nr_segs; seg++) {
- const struct iovec *iv = &iov[seg];
-
- /*
- * If any segment has a negative length, or the cumulative
- * length ever wraps negative then return -EINVAL.
- */
- cnt += iv->iov_len;
- if (unlikely((ssize_t)(cnt|iv->iov_len) < 0))
- return -EINVAL;
- if (access_ok(access_flags, iv->iov_base, iv->iov_len))
- continue;
- if (seg == 0)
- return -EFAULT;
- *nr_segs = seg;
- cnt -= iv->iov_len; /* This segment is no good */
- break;
- }
- *count = cnt;
- return 0;
-}
-EXPORT_SYMBOL(generic_segment_checks);
-
/**
- * generic_file_aio_read - generic filesystem read routine
+ * generic_file_read_iter - generic filesystem read routine
* @iocb: kernel I/O control block
- * @iov: io vector request
- * @nr_segs: number of segments in the iovec
- * @pos: current file position
+ * @iter: destination for the data read
*
- * This is the "read()" routine for all filesystems
+ * This is the "read_iter()" routine for all filesystems
* that can use the page cache directly.
*/
ssize_t
-generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos)
+generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
{
- struct file *filp = iocb->ki_filp;
- ssize_t retval;
- size_t count;
+ struct file *file = iocb->ki_filp;
+ ssize_t retval = 0;
loff_t *ppos = &iocb->ki_pos;
- struct iov_iter i;
-
- count = 0;
- retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
- if (retval)
- return retval;
- iov_iter_init(&i, iov, nr_segs, count, 0);
+ loff_t pos = *ppos;
/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
- if (filp->f_flags & O_DIRECT) {
+ if (file->f_flags & O_DIRECT) {
+ struct address_space *mapping = file->f_mapping;
+ struct inode *inode = mapping->host;
+ size_t count = iov_iter_count(iter);
loff_t size;
- struct address_space *mapping;
- struct inode *inode;
- mapping = filp->f_mapping;
- inode = mapping->host;
if (!count)
goto out; /* skip atime */
size = i_size_read(inode);
retval = filemap_write_and_wait_range(mapping, pos,
- pos + iov_length(iov, nr_segs) - 1);
+ pos + count - 1);
if (!retval) {
- retval = mapping->a_ops->direct_IO(READ, iocb,
- iov, pos, nr_segs);
+ struct iov_iter data = *iter;
+ retval = mapping->a_ops->direct_IO(READ, iocb, &data, pos);
}
+
if (retval > 0) {
*ppos = pos + retval;
- count -= retval;
- /*
- * If we did a short DIO read we need to skip the
- * section of the iov that we've already read data into.
- */
- iov_iter_advance(&i, retval);
+ iov_iter_advance(iter, retval);
}
/*
@@ -1765,17 +1711,17 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
* and return. Otherwise fallthrough to buffered io for
* the rest of the read.
*/
- if (retval < 0 || !count || *ppos >= size) {
- file_accessed(filp);
+ if (retval < 0 || !iov_iter_count(iter) || *ppos >= size) {
+ file_accessed(file);
goto out;
}
}
- retval = do_generic_file_read(filp, ppos, &i, retval);
+ retval = do_generic_file_read(file, ppos, iter, retval);
out:
return retval;
}
-EXPORT_SYMBOL(generic_file_aio_read);
+EXPORT_SYMBOL(generic_file_read_iter);
#ifdef CONFIG_MMU
/**
@@ -2386,9 +2332,7 @@ int pagecache_write_end(struct file *file, struct address_space *mapping,
EXPORT_SYMBOL(pagecache_write_end);
ssize_t
-generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
- unsigned long *nr_segs, loff_t pos,
- size_t count, size_t ocount)
+generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
@@ -2396,11 +2340,9 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
ssize_t written;
size_t write_len;
pgoff_t end;
+ struct iov_iter data;
- if (count != ocount)
- *nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count);
-
- write_len = iov_length(iov, *nr_segs);
+ write_len = iov_iter_count(from);
end = (pos + write_len - 1) >> PAGE_CACHE_SHIFT;
written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1);
@@ -2427,7 +2369,8 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
}
}
- written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs);
+ data = *from;
+ written = mapping->a_ops->direct_IO(WRITE, iocb, &data, pos);
/*
* Finally, try again to invalidate clean pages which might have been
@@ -2444,6 +2387,7 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
if (written > 0) {
pos += written;
+ iov_iter_advance(from, written);
if (pos > i_size_read(inode) && !S_ISBLK(inode->i_mode)) {
i_size_write(inode, pos);
mark_inode_dirty(inode);
@@ -2568,10 +2512,9 @@ again:
EXPORT_SYMBOL(generic_perform_write);
/**
- * __generic_file_aio_write - write data to a file
+ * __generic_file_write_iter - write data to a file
* @iocb: IO state structure (file, offset, etc.)
- * @iov: vector with data to write
- * @nr_segs: number of segments in the vector
+ * @from: iov_iter with data to write
*
* This function does all the work needed for actually writing data to a
* file. It does all basic checks, removes SUID from the file, updates
@@ -2585,26 +2528,16 @@ EXPORT_SYMBOL(generic_perform_write);
* A caller has to handle it. This is mainly due to the fact that we want to
* avoid syncing under i_mutex.
*/
-ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs)
+ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct address_space * mapping = file->f_mapping;
- size_t ocount; /* original count */
- size_t count; /* after file limit checks */
struct inode *inode = mapping->host;
loff_t pos = iocb->ki_pos;
ssize_t written = 0;
ssize_t err;
ssize_t status;
- struct iov_iter from;
-
- ocount = 0;
- err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
- if (err)
- return err;
-
- count = ocount;
+ size_t count = iov_iter_count(from);
/* We can write back this queue in page reclaim */
current->backing_dev_info = mapping->backing_dev_info;
@@ -2615,6 +2548,8 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
if (count == 0)
goto out;
+ iov_iter_truncate(from, count);
+
err = file_remove_suid(file);
if (err)
goto out;
@@ -2623,17 +2558,13 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
if (err)
goto out;
- iov_iter_init(&from, iov, nr_segs, count, 0);
-
/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
if (unlikely(file->f_flags & O_DIRECT)) {
loff_t endbyte;
- written = generic_file_direct_write(iocb, iov, &from.nr_segs, pos,
- count, ocount);
+ written = generic_file_direct_write(iocb, from, pos);
if (written < 0 || written == count)
goto out;
- iov_iter_advance(&from, written);
/*
* direct-io write to a hole: fall through to buffered I/O
@@ -2642,7 +2573,7 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
pos += written;
count -= written;
- status = generic_perform_write(file, &from, pos);
+ status = generic_perform_write(file, from, pos);
/*
* If generic_perform_write() returned a synchronous error
* then we want to return the number of bytes which were
@@ -2674,7 +2605,7 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
*/
}
} else {
- written = generic_perform_write(file, &from, pos);
+ written = generic_perform_write(file, from, pos);
if (likely(written >= 0))
iocb->ki_pos = pos + written;
}
@@ -2682,30 +2613,25 @@ out:
current->backing_dev_info = NULL;
return written ? written : err;
}
-EXPORT_SYMBOL(__generic_file_aio_write);
+EXPORT_SYMBOL(__generic_file_write_iter);
/**
- * generic_file_aio_write - write data to a file
+ * generic_file_write_iter - write data to a file
* @iocb: IO state structure
- * @iov: vector with data to write
- * @nr_segs: number of segments in the vector
- * @pos: position in file where to write
+ * @from: iov_iter with data to write
*
- * This is a wrapper around __generic_file_aio_write() to be used by most
+ * This is a wrapper around __generic_file_write_iter() to be used by most
* filesystems. It takes care of syncing the file in case of O_SYNC file
* and acquires i_mutex as needed.
*/
-ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos)
+ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
ssize_t ret;
- BUG_ON(iocb->ki_pos != pos);
-
mutex_lock(&inode->i_mutex);
- ret = __generic_file_aio_write(iocb, iov, nr_segs);
+ ret = __generic_file_write_iter(iocb, from);
mutex_unlock(&inode->i_mutex);
if (ret > 0) {
@@ -2717,7 +2643,7 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
}
return ret;
}
-EXPORT_SYMBOL(generic_file_aio_write);
+EXPORT_SYMBOL(generic_file_write_iter);
/**
* try_to_release_page() - release old fs-specific metadata on a page
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 10e46cd721de..7b5dbd1517b5 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -1,8 +1,10 @@
#include <linux/export.h>
#include <linux/uio.h>
#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
-size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
+static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
size_t skip, copy, left, wanted;
@@ -72,13 +74,97 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
}
kunmap(page);
done:
+ if (skip == iov->iov_len) {
+ iov++;
+ skip = 0;
+ }
+ i->count -= wanted - bytes;
+ i->nr_segs -= iov - i->iov;
+ i->iov = iov;
+ i->iov_offset = skip;
+ return wanted - bytes;
+}
+
+static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes,
+ struct iov_iter *i)
+{
+ size_t skip, copy, left, wanted;
+ const struct iovec *iov;
+ char __user *buf;
+ void *kaddr, *to;
+
+ if (unlikely(bytes > i->count))
+ bytes = i->count;
+
+ if (unlikely(!bytes))
+ return 0;
+
+ wanted = bytes;
+ iov = i->iov;
+ skip = i->iov_offset;
+ buf = iov->iov_base + skip;
+ copy = min(bytes, iov->iov_len - skip);
+
+ if (!fault_in_pages_readable(buf, copy)) {
+ kaddr = kmap_atomic(page);
+ to = kaddr + offset;
+
+ /* first chunk, usually the only one */
+ left = __copy_from_user_inatomic(to, buf, copy);
+ copy -= left;
+ skip += copy;
+ to += copy;
+ bytes -= copy;
+
+ while (unlikely(!left && bytes)) {
+ iov++;
+ buf = iov->iov_base;
+ copy = min(bytes, iov->iov_len);
+ left = __copy_from_user_inatomic(to, buf, copy);
+ copy -= left;
+ skip = copy;
+ to += copy;
+ bytes -= copy;
+ }
+ if (likely(!bytes)) {
+ kunmap_atomic(kaddr);
+ goto done;
+ }
+ offset = to - kaddr;
+ buf += copy;
+ kunmap_atomic(kaddr);
+ copy = min(bytes, iov->iov_len - skip);
+ }
+ /* Too bad - revert to non-atomic kmap */
+ kaddr = kmap(page);
+ to = kaddr + offset;
+ left = __copy_from_user(to, buf, copy);
+ copy -= left;
+ skip += copy;
+ to += copy;
+ bytes -= copy;
+ while (unlikely(!left && bytes)) {
+ iov++;
+ buf = iov->iov_base;
+ copy = min(bytes, iov->iov_len);
+ left = __copy_from_user(to, buf, copy);
+ copy -= left;
+ skip = copy;
+ to += copy;
+ bytes -= copy;
+ }
+ kunmap(page);
+done:
+ if (skip == iov->iov_len) {
+ iov++;
+ skip = 0;
+ }
i->count -= wanted - bytes;
i->nr_segs -= iov - i->iov;
i->iov = iov;
i->iov_offset = skip;
return wanted - bytes;
}
-EXPORT_SYMBOL(copy_page_to_iter);
static size_t __iovec_copy_from_user_inatomic(char *vaddr,
const struct iovec *iov, size_t base, size_t bytes)
@@ -107,7 +193,7 @@ static size_t __iovec_copy_from_user_inatomic(char *vaddr,
* were successfully copied. If a fault is encountered then return the number of
* bytes which were copied.
*/
-size_t iov_iter_copy_from_user_atomic(struct page *page,
+static size_t copy_from_user_atomic_iovec(struct page *page,
struct iov_iter *i, unsigned long offset, size_t bytes)
{
char *kaddr;
@@ -127,36 +213,8 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
return copied;
}
-EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
-
-/*
- * This has the same sideeffects and return value as
- * iov_iter_copy_from_user_atomic().
- * The difference is that it attempts to resolve faults.
- * Page must not be locked.
- */
-size_t iov_iter_copy_from_user(struct page *page,
- struct iov_iter *i, unsigned long offset, size_t bytes)
-{
- char *kaddr;
- size_t copied;
-
- kaddr = kmap(page);
- if (likely(i->nr_segs == 1)) {
- int left;
- char __user *buf = i->iov->iov_base + i->iov_offset;
- left = __copy_from_user(kaddr + offset, buf, bytes);
- copied = bytes - left;
- } else {
- copied = __iovec_copy_from_user_inatomic(kaddr + offset,
- i->iov, i->iov_offset, bytes);
- }
- kunmap(page);
- return copied;
-}
-EXPORT_SYMBOL(iov_iter_copy_from_user);
-void iov_iter_advance(struct iov_iter *i, size_t bytes)
+static void advance_iovec(struct iov_iter *i, size_t bytes)
{
BUG_ON(i->count < bytes);
@@ -191,7 +249,6 @@ void iov_iter_advance(struct iov_iter *i, size_t bytes)
i->nr_segs = nr_segs;
}
}
-EXPORT_SYMBOL(iov_iter_advance);
/*
* Fault in the first iovec of the given iov_iter, to a maximum length
@@ -204,21 +261,483 @@ EXPORT_SYMBOL(iov_iter_advance);
*/
int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
{
- char __user *buf = i->iov->iov_base + i->iov_offset;
- bytes = min(bytes, i->iov->iov_len - i->iov_offset);
- return fault_in_pages_readable(buf, bytes);
+ if (!(i->type & ITER_BVEC)) {
+ char __user *buf = i->iov->iov_base + i->iov_offset;
+ bytes = min(bytes, i->iov->iov_len - i->iov_offset);
+ return fault_in_pages_readable(buf, bytes);
+ }
+ return 0;
}
EXPORT_SYMBOL(iov_iter_fault_in_readable);
+static unsigned long alignment_iovec(const struct iov_iter *i)
+{
+ const struct iovec *iov = i->iov;
+ unsigned long res;
+ size_t size = i->count;
+ size_t n;
+
+ if (!size)
+ return 0;
+
+ res = (unsigned long)iov->iov_base + i->iov_offset;
+ n = iov->iov_len - i->iov_offset;
+ if (n >= size)
+ return res | size;
+ size -= n;
+ res |= n;
+ while (size > (++iov)->iov_len) {
+ res |= (unsigned long)iov->iov_base | iov->iov_len;
+ size -= iov->iov_len;
+ }
+ res |= (unsigned long)iov->iov_base | size;
+ return res;
+}
+
+void iov_iter_init(struct iov_iter *i, int direction,
+ const struct iovec *iov, unsigned long nr_segs,
+ size_t count)
+{
+ /* It will get better. Eventually... */
+ if (segment_eq(get_fs(), KERNEL_DS))
+ direction |= ITER_KVEC;
+ i->type = direction;
+ i->iov = iov;
+ i->nr_segs = nr_segs;
+ i->iov_offset = 0;
+ i->count = count;
+}
+EXPORT_SYMBOL(iov_iter_init);
+
+static ssize_t get_pages_iovec(struct iov_iter *i,
+ struct page **pages, size_t maxsize,
+ size_t *start)
+{
+ size_t offset = i->iov_offset;
+ const struct iovec *iov = i->iov;
+ size_t len;
+ unsigned long addr;
+ int n;
+ int res;
+
+ len = iov->iov_len - offset;
+ if (len > i->count)
+ len = i->count;
+ if (len > maxsize)
+ len = maxsize;
+ addr = (unsigned long)iov->iov_base + offset;
+ len += *start = addr & (PAGE_SIZE - 1);
+ addr &= ~(PAGE_SIZE - 1);
+ n = (len + PAGE_SIZE - 1) / PAGE_SIZE;
+ res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
+ if (unlikely(res < 0))
+ return res;
+ return (res == n ? len : res * PAGE_SIZE) - *start;
+}
+
+static ssize_t get_pages_alloc_iovec(struct iov_iter *i,
+ struct page ***pages, size_t maxsize,
+ size_t *start)
+{
+ size_t offset = i->iov_offset;
+ const struct iovec *iov = i->iov;
+ size_t len;
+ unsigned long addr;
+ void *p;
+ int n;
+ int res;
+
+ len = iov->iov_len - offset;
+ if (len > i->count)
+ len = i->count;
+ if (len > maxsize)
+ len = maxsize;
+ addr = (unsigned long)iov->iov_base + offset;
+ len += *start = addr & (PAGE_SIZE - 1);
+ addr &= ~(PAGE_SIZE - 1);
+ n = (len + PAGE_SIZE - 1) / PAGE_SIZE;
+
+ p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
+ if (!p)
+ p = vmalloc(n * sizeof(struct page *));
+ if (!p)
+ return -ENOMEM;
+
+ res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
+ if (unlikely(res < 0)) {
+ kvfree(p);
+ return res;
+ }
+ *pages = p;
+ return (res == n ? len : res * PAGE_SIZE) - *start;
+}
+
+static int iov_iter_npages_iovec(const struct iov_iter *i, int maxpages)
+{
+ size_t offset = i->iov_offset;
+ size_t size = i->count;
+ const struct iovec *iov = i->iov;
+ int npages = 0;
+ int n;
+
+ for (n = 0; size && n < i->nr_segs; n++, iov++) {
+ unsigned long addr = (unsigned long)iov->iov_base + offset;
+ size_t len = iov->iov_len - offset;
+ offset = 0;
+ if (unlikely(!len)) /* empty segment */
+ continue;
+ if (len > size)
+ len = size;
+ npages += (addr + len + PAGE_SIZE - 1) / PAGE_SIZE
+ - addr / PAGE_SIZE;
+ if (npages >= maxpages) /* don't bother going further */
+ return maxpages;
+ size -= len;
+ offset = 0;
+ }
+ return min(npages, maxpages);
+}
+
+static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
+{
+ char *from = kmap_atomic(page);
+ memcpy(to, from + offset, len);
+ kunmap_atomic(from);
+}
+
+static void memcpy_to_page(struct page *page, size_t offset, char *from, size_t len)
+{
+ char *to = kmap_atomic(page);
+ memcpy(to + offset, from, len);
+ kunmap_atomic(to);
+}
+
+static size_t copy_page_to_iter_bvec(struct page *page, size_t offset, size_t bytes,
+ struct iov_iter *i)
+{
+ size_t skip, copy, wanted;
+ const struct bio_vec *bvec;
+ void *kaddr, *from;
+
+ if (unlikely(bytes > i->count))
+ bytes = i->count;
+
+ if (unlikely(!bytes))
+ return 0;
+
+ wanted = bytes;
+ bvec = i->bvec;
+ skip = i->iov_offset;
+ copy = min_t(size_t, bytes, bvec->bv_len - skip);
+
+ kaddr = kmap_atomic(page);
+ from = kaddr + offset;
+ memcpy_to_page(bvec->bv_page, skip + bvec->bv_offset, from, copy);
+ skip += copy;
+ from += copy;
+ bytes -= copy;
+ while (bytes) {
+ bvec++;
+ copy = min(bytes, (size_t)bvec->bv_len);
+ memcpy_to_page(bvec->bv_page, bvec->bv_offset, from, copy);
+ skip = copy;
+ from += copy;
+ bytes -= copy;
+ }
+ kunmap_atomic(kaddr);
+ if (skip == bvec->bv_len) {
+ bvec++;
+ skip = 0;
+ }
+ i->count -= wanted - bytes;
+ i->nr_segs -= bvec - i->bvec;
+ i->bvec = bvec;
+ i->iov_offset = skip;
+ return wanted - bytes;
+}
+
+static size_t copy_page_from_iter_bvec(struct page *page, size_t offset, size_t bytes,
+ struct iov_iter *i)
+{
+ size_t skip, copy, wanted;
+ const struct bio_vec *bvec;
+ void *kaddr, *to;
+
+ if (unlikely(bytes > i->count))
+ bytes = i->count;
+
+ if (unlikely(!bytes))
+ return 0;
+
+ wanted = bytes;
+ bvec = i->bvec;
+ skip = i->iov_offset;
+
+ kaddr = kmap_atomic(page);
+
+ to = kaddr + offset;
+
+ copy = min(bytes, bvec->bv_len - skip);
+
+ memcpy_from_page(to, bvec->bv_page, bvec->bv_offset + skip, copy);
+
+ to += copy;
+ skip += copy;
+ bytes -= copy;
+
+ while (bytes) {
+ bvec++;
+ copy = min(bytes, (size_t)bvec->bv_len);
+ memcpy_from_page(to, bvec->bv_page, bvec->bv_offset, copy);
+ skip = copy;
+ to += copy;
+ bytes -= copy;
+ }
+ kunmap_atomic(kaddr);
+ if (skip == bvec->bv_len) {
+ bvec++;
+ skip = 0;
+ }
+ i->count -= wanted;
+ i->nr_segs -= bvec - i->bvec;
+ i->bvec = bvec;
+ i->iov_offset = skip;
+ return wanted;
+}
+
+static size_t copy_from_user_bvec(struct page *page,
+ struct iov_iter *i, unsigned long offset, size_t bytes)
+{
+ char *kaddr;
+ size_t left;
+ const struct bio_vec *bvec;
+ size_t base = i->iov_offset;
+
+ kaddr = kmap_atomic(page);
+ for (left = bytes, bvec = i->bvec; left; bvec++, base = 0) {
+ size_t copy = min(left, bvec->bv_len - base);
+ if (!bvec->bv_len)
+ continue;
+ memcpy_from_page(kaddr + offset, bvec->bv_page,
+ bvec->bv_offset + base, copy);
+ offset += copy;
+ left -= copy;
+ }
+ kunmap_atomic(kaddr);
+ return bytes;
+}
+
+static void advance_bvec(struct iov_iter *i, size_t bytes)
+{
+ BUG_ON(i->count < bytes);
+
+ if (likely(i->nr_segs == 1)) {
+ i->iov_offset += bytes;
+ i->count -= bytes;
+ } else {
+ const struct bio_vec *bvec = i->bvec;
+ size_t base = i->iov_offset;
+ unsigned long nr_segs = i->nr_segs;
+
+ /*
+ * The !iov->iov_len check ensures we skip over unlikely
+ * zero-length segments (without overruning the iovec).
+ */
+ while (bytes || unlikely(i->count && !bvec->bv_len)) {
+ int copy;
+
+ copy = min(bytes, bvec->bv_len - base);
+ BUG_ON(!i->count || i->count < copy);
+ i->count -= copy;
+ bytes -= copy;
+ base += copy;
+ if (bvec->bv_len == base) {
+ bvec++;
+ nr_segs--;
+ base = 0;
+ }
+ }
+ i->bvec = bvec;
+ i->iov_offset = base;
+ i->nr_segs = nr_segs;
+ }
+}
+
+static unsigned long alignment_bvec(const struct iov_iter *i)
+{
+ const struct bio_vec *bvec = i->bvec;
+ unsigned long res;
+ size_t size = i->count;
+ size_t n;
+
+ if (!size)
+ return 0;
+
+ res = bvec->bv_offset + i->iov_offset;
+ n = bvec->bv_len - i->iov_offset;
+ if (n >= size)
+ return res | size;
+ size -= n;
+ res |= n;
+ while (size > (++bvec)->bv_len) {
+ res |= bvec->bv_offset | bvec->bv_len;
+ size -= bvec->bv_len;
+ }
+ res |= bvec->bv_offset | size;
+ return res;
+}
+
+static ssize_t get_pages_bvec(struct iov_iter *i,
+ struct page **pages, size_t maxsize,
+ size_t *start)
+{
+ const struct bio_vec *bvec = i->bvec;
+ size_t len = bvec->bv_len - i->iov_offset;
+ if (len > i->count)
+ len = i->count;
+ if (len > maxsize)
+ len = maxsize;
+ *start = bvec->bv_offset + i->iov_offset;
+
+ get_page(*pages = bvec->bv_page);
+
+ return len;
+}
+
+static ssize_t get_pages_alloc_bvec(struct iov_iter *i,
+ struct page ***pages, size_t maxsize,
+ size_t *start)
+{
+ const struct bio_vec *bvec = i->bvec;
+ size_t len = bvec->bv_len - i->iov_offset;
+ if (len > i->count)
+ len = i->count;
+ if (len > maxsize)
+ len = maxsize;
+ *start = bvec->bv_offset + i->iov_offset;
+
+ *pages = kmalloc(sizeof(struct page *), GFP_KERNEL);
+ if (!*pages)
+ return -ENOMEM;
+
+ get_page(**pages = bvec->bv_page);
+
+ return len;
+}
+
+static int iov_iter_npages_bvec(const struct iov_iter *i, int maxpages)
+{
+ size_t offset = i->iov_offset;
+ size_t size = i->count;
+ const struct bio_vec *bvec = i->bvec;
+ int npages = 0;
+ int n;
+
+ for (n = 0; size && n < i->nr_segs; n++, bvec++) {
+ size_t len = bvec->bv_len - offset;
+ offset = 0;
+ if (unlikely(!len)) /* empty segment */
+ continue;
+ if (len > size)
+ len = size;
+ npages++;
+ if (npages >= maxpages) /* don't bother going further */
+ return maxpages;
+ size -= len;
+ offset = 0;
+ }
+ return min(npages, maxpages);
+}
+
+size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
+ struct iov_iter *i)
+{
+ if (i->type & ITER_BVEC)
+ return copy_page_to_iter_bvec(page, offset, bytes, i);
+ else
+ return copy_page_to_iter_iovec(page, offset, bytes, i);
+}
+EXPORT_SYMBOL(copy_page_to_iter);
+
+size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
+ struct iov_iter *i)
+{
+ if (i->type & ITER_BVEC)
+ return copy_page_from_iter_bvec(page, offset, bytes, i);
+ else
+ return copy_page_from_iter_iovec(page, offset, bytes, i);
+}
+EXPORT_SYMBOL(copy_page_from_iter);
+
+size_t iov_iter_copy_from_user_atomic(struct page *page,
+ struct iov_iter *i, unsigned long offset, size_t bytes)
+{
+ if (i->type & ITER_BVEC)
+ return copy_from_user_bvec(page, i, offset, bytes);
+ else
+ return copy_from_user_atomic_iovec(page, i, offset, bytes);
+}
+EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
+
+void iov_iter_advance(struct iov_iter *i, size_t size)
+{
+ if (i->type & ITER_BVEC)
+ advance_bvec(i, size);
+ else
+ advance_iovec(i, size);
+}
+EXPORT_SYMBOL(iov_iter_advance);
+
/*
* Return the count of just the current iov_iter segment.
*/
size_t iov_iter_single_seg_count(const struct iov_iter *i)
{
- const struct iovec *iov = i->iov;
if (i->nr_segs == 1)
return i->count;
+ else if (i->type & ITER_BVEC)
+ return min(i->count, i->iov->iov_len - i->iov_offset);
else
- return min(i->count, iov->iov_len - i->iov_offset);
+ return min(i->count, i->bvec->bv_len - i->iov_offset);
}
EXPORT_SYMBOL(iov_iter_single_seg_count);
+
+unsigned long iov_iter_alignment(const struct iov_iter *i)
+{
+ if (i->type & ITER_BVEC)
+ return alignment_bvec(i);
+ else
+ return alignment_iovec(i);
+}
+EXPORT_SYMBOL(iov_iter_alignment);
+
+ssize_t iov_iter_get_pages(struct iov_iter *i,
+ struct page **pages, size_t maxsize,
+ size_t *start)
+{
+ if (i->type & ITER_BVEC)
+ return get_pages_bvec(i, pages, maxsize, start);
+ else
+ return get_pages_iovec(i, pages, maxsize, start);
+}
+EXPORT_SYMBOL(iov_iter_get_pages);
+
+ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
+ struct page ***pages, size_t maxsize,
+ size_t *start)
+{
+ if (i->type & ITER_BVEC)
+ return get_pages_alloc_bvec(i, pages, maxsize, start);
+ else
+ return get_pages_alloc_iovec(i, pages, maxsize, start);
+}
+EXPORT_SYMBOL(iov_iter_get_pages_alloc);
+
+int iov_iter_npages(const struct iov_iter *i, int maxpages)
+{
+ if (i->type & ITER_BVEC)
+ return iov_iter_npages_bvec(i, maxpages);
+ else
+ return iov_iter_npages_iovec(i, maxpages);
+}
+EXPORT_SYMBOL(iov_iter_npages);
diff --git a/mm/page_io.c b/mm/page_io.c
index 58b50d2901fe..243a9b76e5ce 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -264,9 +264,17 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
struct kiocb kiocb;
struct file *swap_file = sis->swap_file;
struct address_space *mapping = swap_file->f_mapping;
- struct iovec iov = {
- .iov_base = kmap(page),
- .iov_len = PAGE_SIZE,
+ struct bio_vec bv = {
+ .bv_page = page,
+ .bv_len = PAGE_SIZE,
+ .bv_offset = 0
+ };
+ struct iov_iter from = {
+ .type = ITER_BVEC | WRITE,
+ .count = PAGE_SIZE,
+ .iov_offset = 0,
+ .nr_segs = 1,
+ .bvec = &bv
};
init_sync_kiocb(&kiocb, swap_file);
@@ -275,10 +283,9 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
set_page_writeback(page);
unlock_page(page);
- ret = mapping->a_ops->direct_IO(KERNEL_WRITE,
- &kiocb, &iov,
- kiocb.ki_pos, 1);
- kunmap(page);
+ ret = mapping->a_ops->direct_IO(ITER_BVEC | WRITE,
+ &kiocb, &from,
+ kiocb.ki_pos);
if (ret == PAGE_SIZE) {
count_vm_event(PSWPOUT);
ret = 0;
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 8505c9262b35..5077afcd9e11 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -46,11 +46,7 @@ static int process_vm_rw_pages(struct page **pages,
copy = len;
if (vm_write) {
- if (copy > iov_iter_count(iter))
- copy = iov_iter_count(iter);
- copied = iov_iter_copy_from_user(page, iter,
- offset, copy);
- iov_iter_advance(iter, copied);
+ copied = copy_page_from_iter(page, offset, copy, iter);
set_page_dirty_lock(page);
} else {
copied = copy_page_to_iter(page, offset, copy, iter);
@@ -278,7 +274,7 @@ static ssize_t process_vm_rw(pid_t pid,
if (rc <= 0)
goto free_iovecs;
- iov_iter_init(&iter, iov_l, liovcnt, rc, 0);
+ iov_iter_init(&iter, vm_write ? WRITE : READ, iov_l, liovcnt, rc);
rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,
iovstack_r, &iov_r);
@@ -341,7 +337,7 @@ compat_process_vm_rw(compat_pid_t pid,
&iov_l);
if (rc <= 0)
goto free_iovecs;
- iov_iter_init(&iter, iov_l, liovcnt, rc, 0);
+ iov_iter_init(&iter, vm_write ? WRITE : READ, iov_l, liovcnt, rc);
rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,
UIO_FASTIOV, iovstack_r,
&iov_r);
diff --git a/mm/shmem.c b/mm/shmem.c
index 5402481c28d1..f484c276e994 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1406,8 +1406,7 @@ shmem_write_end(struct file *file, struct address_space *mapping,
return copied;
}
-static ssize_t shmem_file_aio_read(struct kiocb *iocb,
- const struct iovec *iov, unsigned long nr_segs, loff_t pos)
+static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
@@ -1416,15 +1415,8 @@ static ssize_t shmem_file_aio_read(struct kiocb *iocb,
unsigned long offset;
enum sgp_type sgp = SGP_READ;
int error = 0;
- ssize_t retval;
- size_t count;
+ ssize_t retval = 0;
loff_t *ppos = &iocb->ki_pos;
- struct iov_iter iter;
-
- retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
- if (retval)
- return retval;
- iov_iter_init(&iter, iov, nr_segs, count, 0);
/*
* Might this read be for a stacking filesystem? Then when reading
@@ -1500,14 +1492,14 @@ static ssize_t shmem_file_aio_read(struct kiocb *iocb,
* Ok, we have the page, and it's up-to-date, so
* now we can copy it to user space...
*/
- ret = copy_page_to_iter(page, offset, nr, &iter);
+ ret = copy_page_to_iter(page, offset, nr, to);
retval += ret;
offset += ret;
index += offset >> PAGE_CACHE_SHIFT;
offset &= ~PAGE_CACHE_MASK;
page_cache_release(page);
- if (!iov_iter_count(&iter))
+ if (!iov_iter_count(to))
break;
if (ret < nr) {
error = -EFAULT;
@@ -2629,13 +2621,13 @@ static const struct file_operations shmem_file_operations = {
.mmap = shmem_mmap,
#ifdef CONFIG_TMPFS
.llseek = shmem_file_llseek,
- .read = do_sync_read,
- .write = do_sync_write,
- .aio_read = shmem_file_aio_read,
- .aio_write = generic_file_aio_write,
+ .read = new_sync_read,
+ .write = new_sync_write,
+ .read_iter = shmem_file_read_iter,
+ .write_iter = generic_file_write_iter,
.fsync = noop_fsync,
.splice_read = shmem_file_splice_read,
- .splice_write = generic_file_splice_write,
+ .splice_write = iter_file_splice_write,
.fallocate = shmem_fallocate,
#endif
};
diff --git a/mm/vmscan.c b/mm/vmscan.c
index e01ded365440..0f16ffe8eb67 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -464,7 +464,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
* stalls if we need to run get_block(). We could test
* PagePrivate for that.
*
- * If this process is currently in __generic_file_aio_write() against
+ * If this process is currently in __generic_file_write_iter() against
* this page's queue, we can perform writeback even if that
* will block.
*