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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Browse source 
Pull vfs updates from Al Viro:
 "The first vfs pile, with deep apologies for being very late in this
  window.

  Assorted cleanups and fixes, plus a large preparatory part of iov_iter
  work.  There's a lot more of that, but it'll probably go into the next
  merge window - it *does* shape up nicely, removes a lot of
  boilerplate, gets rid of locking inconsistencie between aio_write and
  splice_write and I hope to get Kent's direct-io rewrite merged into
  the same queue, but some of the stuff after this point is having
  (mostly trivial) conflicts with the things already merged into
  mainline and with some I want more testing.

  This one passes LTP and xfstests without regressions, in addition to
  usual beating.  BTW, readahead02 in ltp syscalls testsuite has started
  giving failures since "mm/readahead.c: fix readahead failure for
  memoryless NUMA nodes and limit readahead pages" - might be a false
  positive, might be a real regression..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  missing bits of "splice: fix racy pipe->buffers uses"
  cifs: fix the race in cifs_writev()
  ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
  kill generic_file_buffered_write()
  ocfs2_file_aio_write(): switch to generic_perform_write()
  ceph_aio_write(): switch to generic_perform_write()
  xfs_file_buffered_aio_write(): switch to generic_perform_write()
  export generic_perform_write(), start getting rid of generic_file_buffer_write()
  generic_file_direct_write(): get rid of ppos argument
  btrfs_file_aio_write(): get rid of ppos
  kill the 5th argument of generic_file_buffered_write()
  kill the 4th argument of __generic_file_aio_write()
  lustre: don't open-code kernel_recvmsg()
  ocfs2: don't open-code kernel_recvmsg()
  drbd: don't open-code kernel_recvmsg()
  constify blk_rq_map_user_iov() and friends
  lustre: switch to kernel_sendmsg()
  ocfs2: don't open-code kernel_sendmsg()
  take iov_iter stuff to mm/iov_iter.c
  process_vm_access: tidy up a bit
  ...
This commit is contained in:
Linus Torvalds 2014-04-12 14:49:50 -07:00
commit 5166701b36
76 changed files with 911 additions and 1537 deletions
Download patch file Download diff file Expand all files Collapse all files

3
mm/Makefile
View file

@ -17,7 +17,8 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \
util.o mmzone.o vmstat.o backing-dev.o \
mm_init.o mmu_context.o percpu.o slab_common.o \
compaction.o balloon_compaction.o vmacache.o \
interval_tree.o list_lru.o workingset.o $(mmu-y)
interval_tree.o list_lru.o workingset.o \
iov_iter.o $(mmu-y)
obj-y += init-mm.o

344
mm/filemap.c
View file

@ -77,7 +77,7 @@
* ->mmap_sem
* ->lock_page (access_process_vm)
*
* ->i_mutex (generic_file_buffered_write)
* ->i_mutex (generic_perform_write)
* ->mmap_sem (fault_in_pages_readable->do_page_fault)
*
* bdi->wb.list_lock
@ -1428,7 +1428,8 @@ static void shrink_readahead_size_eio(struct file *filp,
* do_generic_file_read - generic file read routine
* @filp: the file to read
* @ppos: current file position
* @desc: read_descriptor
* @iter: data destination
* @written: already copied
*
* This is a generic file read routine, and uses the
* mapping->a_ops->readpage() function for the actual low-level stuff.
@ -1436,8 +1437,8 @@ static void shrink_readahead_size_eio(struct file *filp,
* This is really ugly. But the goto's actually try to clarify some
* of the logic when it comes to error handling etc.
*/
static void do_generic_file_read(struct file *filp, loff_t *ppos,
read_descriptor_t *desc)
static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos,
struct iov_iter *iter, ssize_t written)
{
struct address_space *mapping = filp->f_mapping;
struct inode *inode = mapping->host;
@ -1447,12 +1448,12 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos,
pgoff_t prev_index;
unsigned long offset; /* offset into pagecache page */
unsigned int prev_offset;
int error;
int error = 0;
index = *ppos >> PAGE_CACHE_SHIFT;
prev_index = ra->prev_pos >> PAGE_CACHE_SHIFT;
prev_offset = ra->prev_pos & (PAGE_CACHE_SIZE-1);
last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
last_index = (*ppos + iter->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
offset = *ppos & ~PAGE_CACHE_MASK;
for (;;) {
@ -1487,7 +1488,7 @@ find_page:
if (!page->mapping)
goto page_not_up_to_date_locked;
if (!mapping->a_ops->is_partially_uptodate(page,
desc, offset))
offset, iter->count))
goto page_not_up_to_date_locked;
unlock_page(page);
}
@ -1537,24 +1538,23 @@ page_ok:
/*
* Ok, we have the page, and it's up-to-date, so
* now we can copy it to user space...
*
* The file_read_actor routine returns how many bytes were
* actually used..
* NOTE! This may not be the same as how much of a user buffer
* we filled up (we may be padding etc), so we can only update
* "pos" here (the actor routine has to update the user buffer
* pointers and the remaining count).
*/
ret = file_read_actor(desc, page, offset, nr);
ret = copy_page_to_iter(page, offset, nr, iter);
offset += ret;
index += offset >> PAGE_CACHE_SHIFT;
offset &= ~PAGE_CACHE_MASK;
prev_offset = offset;
page_cache_release(page);
if (ret == nr && desc->count)
continue;
goto out;
written += ret;
if (!iov_iter_count(iter))
goto out;
if (ret < nr) {
error = -EFAULT;
goto out;
}
continue;
page_not_up_to_date:
/* Get exclusive access to the page ... */
@ -1589,6 +1589,7 @@ readpage:
if (unlikely(error)) {
if (error == AOP_TRUNCATED_PAGE) {
page_cache_release(page);
error = 0;
goto find_page;
}
goto readpage_error;
@ -1619,7 +1620,6 @@ readpage:
readpage_error:
/* UHHUH! A synchronous read error occurred. Report it */
desc->error = error;
page_cache_release(page);
goto out;
@ -1630,16 +1630,17 @@ no_cached_page:
*/
page = page_cache_alloc_cold(mapping);
if (!page) {
desc->error = -ENOMEM;
error = -ENOMEM;
goto out;
}
error = add_to_page_cache_lru(page, mapping,
index, GFP_KERNEL);
if (error) {
page_cache_release(page);
if (error == -EEXIST)
if (error == -EEXIST) {
error = 0;
goto find_page;
desc->error = error;
}
goto out;
}
goto readpage;
@ -1652,44 +1653,7 @@ out:
*ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset;
file_accessed(filp);
}
int file_read_actor(read_descriptor_t *desc, struct page *page,
unsigned long offset, unsigned long size)
{
char *kaddr;
unsigned long left, count = desc->count;
if (size > count)
size = count;
/*
* Faults on the destination of a read are common, so do it before
* taking the kmap.
*/
if (!fault_in_pages_writeable(desc->arg.buf, size)) {
kaddr = kmap_atomic(page);
left = __copy_to_user_inatomic(desc->arg.buf,
kaddr + offset, size);
kunmap_atomic(kaddr);
if (left == 0)
goto success;
}
/* Do it the slow way */
kaddr = kmap(page);
left = __copy_to_user(desc->arg.buf, kaddr + offset, size);
kunmap(page);
if (left) {
size -= left;
desc->error = -EFAULT;
}
success:
desc->count = count - size;
desc->written += size;
desc->arg.buf += size;
return size;
return written ? written : error;
}
/*
@ -1747,14 +1711,15 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
{
struct file *filp = iocb->ki_filp;
ssize_t retval;
unsigned long seg = 0;
size_t count;
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);
/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
if (filp->f_flags & O_DIRECT) {
@ -1776,6 +1741,11 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
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);
}
/*
@ -1792,39 +1762,7 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
}
}
count = retval;
for (seg = 0; seg < nr_segs; seg++) {
read_descriptor_t desc;
loff_t offset = 0;
/*
* If we did a short DIO read we need to skip the section of the
* iov that we've already read data into.
*/
if (count) {
if (count > iov[seg].iov_len) {
count -= iov[seg].iov_len;
continue;
}
offset = count;
count = 0;
}
desc.written = 0;
desc.arg.buf = iov[seg].iov_base + offset;
desc.count = iov[seg].iov_len - offset;
if (desc.count == 0)
continue;
desc.error = 0;
do_generic_file_read(filp, ppos, &desc);
retval += desc.written;
if (desc.error) {
retval = retval ?: desc.error;
break;
}
if (desc.count > 0)
break;
}
retval = do_generic_file_read(filp, ppos, &i, retval);
out:
return retval;
}
@ -2335,150 +2273,6 @@ struct page *read_cache_page_gfp(struct address_space *mapping,
}
EXPORT_SYMBOL(read_cache_page_gfp);
static size_t __iovec_copy_from_user_inatomic(char *vaddr,
const struct iovec *iov, size_t base, size_t bytes)
{
size_t copied = 0, left = 0;
while (bytes) {
char __user *buf = iov->iov_base + base;
int copy = min(bytes, iov->iov_len - base);
base = 0;
left = __copy_from_user_inatomic(vaddr, buf, copy);
copied += copy;
bytes -= copy;
vaddr += copy;
iov++;
if (unlikely(left))
break;
}
return copied - left;
}
/*
* Copy as much as we can into the page and return the number of bytes which
* 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,
struct iov_iter *i, unsigned long offset, size_t bytes)
{
char *kaddr;
size_t copied;
BUG_ON(!in_atomic());
kaddr = kmap_atomic(page);
if (likely(i->nr_segs == 1)) {
int left;
char __user *buf = i->iov->iov_base + i->iov_offset;
left = __copy_from_user_inatomic(kaddr + offset, buf, bytes);
copied = bytes - left;
} else {
copied = __iovec_copy_from_user_inatomic(kaddr + offset,
i->iov, i->iov_offset, bytes);
}
kunmap_atomic(kaddr);
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)
{
BUG_ON(i->count < bytes);
if (likely(i->nr_segs == 1)) {
i->iov_offset += bytes;
i->count -= bytes;
} else {
const struct iovec *iov = i->iov;
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 && !iov->iov_len)) {
int copy;
copy = min(bytes, iov->iov_len - base);
BUG_ON(!i->count || i->count < copy);
i->count -= copy;
bytes -= copy;
base += copy;
if (iov->iov_len == base) {
iov++;
nr_segs--;
base = 0;
}
}
i->iov = iov;
i->iov_offset = base;
i->nr_segs = nr_segs;
}
}
EXPORT_SYMBOL(iov_iter_advance);
/*
* Fault in the first iovec of the given iov_iter, to a maximum length
* of bytes. Returns 0 on success, or non-zero if the memory could not be
* accessed (ie. because it is an invalid address).
*
* writev-intensive code may want this to prefault several iovecs -- that
* would be possible (callers must not rely on the fact that _only_ the
* first iovec will be faulted with the current implementation).
*/
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);
}
EXPORT_SYMBOL(iov_iter_fault_in_readable);
/*
* 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
return min(i->count, iov->iov_len - i->iov_offset);
}
EXPORT_SYMBOL(iov_iter_single_seg_count);
/*
* Performs necessary checks before doing a write
*
@ -2585,7 +2379,7 @@ 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, loff_t *ppos,
unsigned long *nr_segs, loff_t pos,
size_t count, size_t ocount)
{
struct file *file = iocb->ki_filp;
@ -2646,7 +2440,7 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
i_size_write(inode, pos);
mark_inode_dirty(inode);
}
*ppos = pos;
iocb->ki_pos = pos;
}
out:
return written;
@ -2692,7 +2486,7 @@ found:
}
EXPORT_SYMBOL(grab_cache_page_write_begin);
static ssize_t generic_perform_write(struct file *file,
ssize_t generic_perform_write(struct file *file,
struct iov_iter *i, loff_t pos)
{
struct address_space *mapping = file->f_mapping;
@ -2742,9 +2536,7 @@ again:
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
pagefault_disable();
copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
pagefault_enable();
flush_dcache_page(page);
mark_page_accessed(page);
@ -2782,27 +2574,7 @@ again:
return written ? written : status;
}
ssize_t
generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos, loff_t *ppos,
size_t count, ssize_t written)
{
struct file *file = iocb->ki_filp;
ssize_t status;
struct iov_iter i;
iov_iter_init(&i, iov, nr_segs, count, written);
status = generic_perform_write(file, &i, pos);
if (likely(status >= 0)) {
written += status;
*ppos = pos + status;
}
return written ? written : status;
}
EXPORT_SYMBOL(generic_file_buffered_write);
EXPORT_SYMBOL(generic_perform_write);
/**
* __generic_file_aio_write - write data to a file
@ -2824,16 +2596,18 @@ EXPORT_SYMBOL(generic_file_buffered_write);
* avoid syncing under i_mutex.
*/
ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t *ppos)
unsigned long nr_segs)
{
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;
ssize_t written;
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);
@ -2841,12 +2615,9 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
return err;
count = ocount;
pos = *ppos;
/* We can write back this queue in page reclaim */
current->backing_dev_info = mapping->backing_dev_info;
written = 0;
err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
if (err)
goto out;
@ -2862,45 +2633,47 @@ 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;
ssize_t written_buffered;
written = generic_file_direct_write(iocb, iov, &nr_segs, pos,
ppos, count, ocount);
written = generic_file_direct_write(iocb, iov, &from.nr_segs, pos,
count, ocount);
if (written < 0 || written == count)
goto out;
iov_iter_advance(&from, written);
/*
* direct-io write to a hole: fall through to buffered I/O
* for completing the rest of the request.
*/
pos += written;
count -= written;
written_buffered = generic_file_buffered_write(iocb, iov,
nr_segs, pos, ppos, count,
written);
status = generic_perform_write(file, &from, pos);
/*
* If generic_file_buffered_write() retuned a synchronous error
* If generic_perform_write() returned a synchronous error
* then we want to return the number of bytes which were
* direct-written, or the error code if that was zero. Note
* that this differs from normal direct-io semantics, which
* will return -EFOO even if some bytes were written.
*/
if (written_buffered < 0) {
err = written_buffered;
if (unlikely(status < 0) && !written) {
err = status;
goto out;
}
iocb->ki_pos = pos + status;
/*
* We need to ensure that the page cache pages are written to
* disk and invalidated to preserve the expected O_DIRECT
* semantics.
*/
endbyte = pos + written_buffered - written - 1;
endbyte = pos + status - 1;
err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
if (err == 0) {
written = written_buffered;
written += status;
invalidate_mapping_pages(mapping,
pos >> PAGE_CACHE_SHIFT,
endbyte >> PAGE_CACHE_SHIFT);
@ -2911,8 +2684,9 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
*/
}
} else {
written = generic_file_buffered_write(iocb, iov, nr_segs,
pos, ppos, count, written);
written = generic_perform_write(file, &from, pos);
if (likely(written >= 0))
iocb->ki_pos = pos + written;
}
out:
current->backing_dev_info = NULL;
@ -2941,7 +2715,7 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
BUG_ON(iocb->ki_pos != pos);
mutex_lock(&inode->i_mutex);
ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
ret = __generic_file_aio_write(iocb, iov, nr_segs);
mutex_unlock(&inode->i_mutex);
if (ret > 0) {

224
mm/iov_iter.c Normal file
View file

@ -0,0 +1,224 @@
#include <linux/export.h>
#include <linux/uio.h>
#include <linux/pagemap.h>
size_t copy_page_to_iter(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, *from;
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_writeable(buf, copy)) {
kaddr = kmap_atomic(page);
from = kaddr + offset;
/* first chunk, usually the only one */
left = __copy_to_user_inatomic(buf, from, copy);
copy -= left;
skip += copy;
from += copy;
bytes -= copy;
while (unlikely(!left && bytes)) {
iov++;
buf = iov->iov_base;
copy = min(bytes, iov->iov_len);
left = __copy_to_user_inatomic(buf, from, copy);
copy -= left;
skip = copy;
from += copy;
bytes -= copy;
}
if (likely(!bytes)) {
kunmap_atomic(kaddr);
goto done;
}
offset = from - kaddr;
buf += copy;
kunmap_atomic(kaddr);
copy = min(bytes, iov->iov_len - skip);
}
/* Too bad - revert to non-atomic kmap */
kaddr = kmap(page);
from = kaddr + offset;
left = __copy_to_user(buf, from, copy);
copy -= left;
skip += copy;
from += copy;
bytes -= copy;
while (unlikely(!left && bytes)) {
iov++;
buf = iov->iov_base;
copy = min(bytes, iov->iov_len);
left = __copy_to_user(buf, from, copy);
copy -= left;
skip = copy;
from += copy;
bytes -= copy;
}
kunmap(page);
done:
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)
{
size_t copied = 0, left = 0;
while (bytes) {
char __user *buf = iov->iov_base + base;
int copy = min(bytes, iov->iov_len - base);
base = 0;
left = __copy_from_user_inatomic(vaddr, buf, copy);
copied += copy;
bytes -= copy;
vaddr += copy;
iov++;
if (unlikely(left))
break;
}
return copied - left;
}
/*
* Copy as much as we can into the page and return the number of bytes which
* 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,
struct iov_iter *i, unsigned long offset, size_t bytes)
{
char *kaddr;
size_t copied;
kaddr = kmap_atomic(page);
if (likely(i->nr_segs == 1)) {
int left;
char __user *buf = i->iov->iov_base + i->iov_offset;
left = __copy_from_user_inatomic(kaddr + offset, buf, bytes);
copied = bytes - left;
} else {
copied = __iovec_copy_from_user_inatomic(kaddr + offset,
i->iov, i->iov_offset, bytes);
}
kunmap_atomic(kaddr);
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)
{
BUG_ON(i->count < bytes);
if (likely(i->nr_segs == 1)) {
i->iov_offset += bytes;
i->count -= bytes;
} else {
const struct iovec *iov = i->iov;
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 && !iov->iov_len)) {
int copy;
copy = min(bytes, iov->iov_len - base);
BUG_ON(!i->count || i->count < copy);
i->count -= copy;
bytes -= copy;
base += copy;
if (iov->iov_len == base) {
iov++;
nr_segs--;
base = 0;
}
}
i->iov = iov;
i->iov_offset = base;
i->nr_segs = nr_segs;
}
}
EXPORT_SYMBOL(iov_iter_advance);
/*
* Fault in the first iovec of the given iov_iter, to a maximum length
* of bytes. Returns 0 on success, or non-zero if the memory could not be
* accessed (ie. because it is an invalid address).
*
* writev-intensive code may want this to prefault several iovecs -- that
* would be possible (callers must not rely on the fact that _only_ the
* first iovec will be faulted with the current implementation).
*/
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);
}
EXPORT_SYMBOL(iov_iter_fault_in_readable);
/*
* 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
return min(i->count, iov->iov_len - i->iov_offset);
}
EXPORT_SYMBOL(iov_iter_single_seg_count);

246
mm/process_vm_access.c
View file

@ -23,129 +23,44 @@
/**
* process_vm_rw_pages - read/write pages from task specified
* @task: task to read/write from
* @mm: mm for task
* @process_pages: struct pages area that can store at least
* nr_pages_to_copy struct page pointers
* @pa: address of page in task to start copying from/to
* @pages: array of pointers to pages we want to copy
* @start_offset: offset in page to start copying from/to
* @len: number of bytes to copy
* @lvec: iovec array specifying where to copy to/from
* @lvec_cnt: number of elements in iovec array
* @lvec_current: index in iovec array we are up to
* @lvec_offset: offset in bytes from current iovec iov_base we are up to
* @iter: where to copy to/from locally
* @vm_write: 0 means copy from, 1 means copy to
* @nr_pages_to_copy: number of pages to copy
* @bytes_copied: returns number of bytes successfully copied
* Returns 0 on success, error code otherwise
*/
static int process_vm_rw_pages(struct task_struct *task,
struct mm_struct *mm,
struct page **process_pages,
unsigned long pa,
unsigned long start_offset,
unsigned long len,
const struct iovec *lvec,
unsigned long lvec_cnt,
unsigned long *lvec_current,
size_t *lvec_offset,
int vm_write,
unsigned int nr_pages_to_copy,
ssize_t *bytes_copied)
static int process_vm_rw_pages(struct page **pages,
unsigned offset,
size_t len,
struct iov_iter *iter,
int vm_write)
{
int pages_pinned;
void *target_kaddr;
int pgs_copied = 0;
int j;
int ret;
ssize_t bytes_to_copy;
ssize_t rc = 0;
*bytes_copied = 0;
/* Get the pages we're interested in */
down_read(&mm->mmap_sem);
pages_pinned = get_user_pages(task, mm, pa,
nr_pages_to_copy,
vm_write, 0, process_pages, NULL);
up_read(&mm->mmap_sem);
if (pages_pinned != nr_pages_to_copy) {
rc = -EFAULT;
goto end;
}
/* Do the copy for each page */
for (pgs_copied = 0;
(pgs_copied < nr_pages_to_copy) && (*lvec_current < lvec_cnt);
pgs_copied++) {
/* Make sure we have a non zero length iovec */
while (*lvec_current < lvec_cnt
&& lvec[*lvec_current].iov_len == 0)
(*lvec_current)++;
if (*lvec_current == lvec_cnt)
break;
while (len && iov_iter_count(iter)) {
struct page *page = *pages++;
size_t copy = PAGE_SIZE - offset;
size_t copied;
/*
* Will copy smallest of:
* - bytes remaining in page
* - bytes remaining in destination iovec
*/
bytes_to_copy = min_t(ssize_t, PAGE_SIZE - start_offset,
len - *bytes_copied);
bytes_to_copy = min_t(ssize_t, bytes_to_copy,
lvec[*lvec_current].iov_len
- *lvec_offset);
if (copy > len)
copy = len;
target_kaddr = kmap(process_pages[pgs_copied]) + start_offset;
if (vm_write)
ret = copy_from_user(target_kaddr,
lvec[*lvec_current].iov_base
+ *lvec_offset,
bytes_to_copy);
else
ret = copy_to_user(lvec[*lvec_current].iov_base
+ *lvec_offset,
target_kaddr, bytes_to_copy);
kunmap(process_pages[pgs_copied]);
if (ret) {
*bytes_copied += bytes_to_copy - ret;
pgs_copied++;
rc = -EFAULT;
goto end;
}
*bytes_copied += bytes_to_copy;
*lvec_offset += bytes_to_copy;
if (*lvec_offset == lvec[*lvec_current].iov_len) {
/*
* Need to copy remaining part of page into the
* next iovec if there are any bytes left in page
*/
(*lvec_current)++;
*lvec_offset = 0;
start_offset = (start_offset + bytes_to_copy)
% PAGE_SIZE;
if (start_offset)
pgs_copied--;
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);
set_page_dirty_lock(page);
} else {
start_offset = 0;
copied = copy_page_to_iter(page, offset, copy, iter);
}
len -= copied;
if (copied < copy && iov_iter_count(iter))
return -EFAULT;
offset = 0;
}
end:
if (vm_write) {
for (j = 0; j < pages_pinned; j++) {
if (j < pgs_copied)
set_page_dirty_lock(process_pages[j]);
put_page(process_pages[j]);
}
} else {
for (j = 0; j < pages_pinned; j++)
put_page(process_pages[j]);
}
return rc;
return 0;
}
/* Maximum number of pages kmalloc'd to hold struct page's during copy */
@ -155,67 +70,60 @@ end:
* process_vm_rw_single_vec - read/write pages from task specified
* @addr: start memory address of target process
* @len: size of area to copy to/from
* @lvec: iovec array specifying where to copy to/from locally
* @lvec_cnt: number of elements in iovec array
* @lvec_current: index in iovec array we are up to
* @lvec_offset: offset in bytes from current iovec iov_base we are up to
* @iter: where to copy to/from locally
* @process_pages: struct pages area that can store at least
* nr_pages_to_copy struct page pointers
* @mm: mm for task
* @task: task to read/write from
* @vm_write: 0 means copy from, 1 means copy to
* @bytes_copied: returns number of bytes successfully copied
* Returns 0 on success or on failure error code
*/
static int process_vm_rw_single_vec(unsigned long addr,
unsigned long len,
const struct iovec *lvec,
unsigned long lvec_cnt,
unsigned long *lvec_current,
size_t *lvec_offset,
struct iov_iter *iter,
struct page **process_pages,
struct mm_struct *mm,
struct task_struct *task,
int vm_write,
ssize_t *bytes_copied)
int vm_write)
{
unsigned long pa = addr & PAGE_MASK;
unsigned long start_offset = addr - pa;
unsigned long nr_pages;
ssize_t bytes_copied_loop;
ssize_t rc = 0;
unsigned long nr_pages_copied = 0;
unsigned long nr_pages_to_copy;
unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
/ sizeof(struct pages *);
*bytes_copied = 0;
/* Work out address and page range required */
if (len == 0)
return 0;
nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
while ((nr_pages_copied < nr_pages) && (*lvec_current < lvec_cnt)) {
nr_pages_to_copy = min(nr_pages - nr_pages_copied,
max_pages_per_loop);
while (!rc && nr_pages && iov_iter_count(iter)) {
int pages = min(nr_pages, max_pages_per_loop);
size_t bytes;
rc = process_vm_rw_pages(task, mm, process_pages, pa,
start_offset, len,
lvec, lvec_cnt,
lvec_current, lvec_offset,
vm_write, nr_pages_to_copy,
&bytes_copied_loop);
/* Get the pages we're interested in */
down_read(&mm->mmap_sem);
pages = get_user_pages(task, mm, pa, pages,
vm_write, 0, process_pages, NULL);
up_read(&mm->mmap_sem);
if (pages <= 0)
return -EFAULT;
bytes = pages * PAGE_SIZE - start_offset;
if (bytes > len)
bytes = len;
rc = process_vm_rw_pages(process_pages,
start_offset, bytes, iter,
vm_write);
len -= bytes;
start_offset = 0;
*bytes_copied += bytes_copied_loop;
if (rc < 0) {
return rc;
} else {
len -= bytes_copied_loop;
nr_pages_copied += nr_pages_to_copy;
pa += nr_pages_to_copy * PAGE_SIZE;
}
nr_pages -= pages;
pa += pages * PAGE_SIZE;
while (pages)
put_page(process_pages[--pages]);
}
return rc;
@ -228,8 +136,7 @@ static int process_vm_rw_single_vec(unsigned long addr,
/**
* process_vm_rw_core - core of reading/writing pages from task specified
* @pid: PID of process to read/write from/to
* @lvec: iovec array specifying where to copy to/from locally
* @liovcnt: size of lvec array
* @iter: where to copy to/from locally
* @rvec: iovec array specifying where to copy to/from in the other process
* @riovcnt: size of rvec array
* @flags: currently unused
@ -238,8 +145,7 @@ static int process_vm_rw_single_vec(unsigned long addr,
* return less bytes than expected if an error occurs during the copying
* process.
*/
static ssize_t process_vm_rw_core(pid_t pid, const struct iovec *lvec,
unsigned long liovcnt,
static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
const struct iovec *rvec,
unsigned long riovcnt,
unsigned long flags, int vm_write)
@ -250,13 +156,10 @@ static ssize_t process_vm_rw_core(pid_t pid, const struct iovec *lvec,
struct mm_struct *mm;
unsigned long i;
ssize_t rc = 0;
ssize_t bytes_copied_loop;
ssize_t bytes_copied = 0;
unsigned long nr_pages = 0;
unsigned long nr_pages_iov;
unsigned long iov_l_curr_idx = 0;
size_t iov_l_curr_offset = 0;
ssize_t iov_len;
size_t total_len = iov_iter_count(iter);
/*
* Work out how many pages of struct pages we're going to need
@ -310,24 +213,20 @@ static ssize_t process_vm_rw_core(pid_t pid, const struct iovec *lvec,
goto put_task_struct;
}
for (i = 0; i < riovcnt && iov_l_curr_idx < liovcnt; i++) {
for (i = 0; i < riovcnt && iov_iter_count(iter) && !rc; i++)
rc = process_vm_rw_single_vec(
(unsigned long)rvec[i].iov_base, rvec[i].iov_len,
lvec, liovcnt, &iov_l_curr_idx, &iov_l_curr_offset,
process_pages, mm, task, vm_write, &bytes_copied_loop);
bytes_copied += bytes_copied_loop;
if (rc != 0) {
/* If we have managed to copy any data at all then
we return the number of bytes copied. Otherwise
we return the error code */
if (bytes_copied)
rc = bytes_copied;
goto put_mm;
}
}
iter, process_pages, mm, task, vm_write);
/* copied = space before - space after */
total_len -= iov_iter_count(iter);
/* If we have managed to copy any data at all then
we return the number of bytes copied. Otherwise
we return the error code */
if (total_len)
rc = total_len;
rc = bytes_copied;
put_mm:
mmput(mm);
put_task_struct:
@ -363,6 +262,7 @@ static ssize_t process_vm_rw(pid_t pid,
struct iovec iovstack_r[UIO_FASTIOV];
struct iovec *iov_l = iovstack_l;
struct iovec *iov_r = iovstack_r;
struct iov_iter iter;
ssize_t rc;
if (flags != 0)
@ -378,13 +278,14 @@ static ssize_t process_vm_rw(pid_t pid,
if (rc <= 0)
goto free_iovecs;
iov_iter_init(&iter, iov_l, liovcnt, rc, 0);
rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,
iovstack_r, &iov_r);
if (rc <= 0)
goto free_iovecs;
rc = process_vm_rw_core(pid, iov_l, liovcnt, iov_r, riovcnt, flags,
vm_write);
rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
free_iovecs:
if (iov_r != iovstack_r)
@ -424,6 +325,7 @@ compat_process_vm_rw(compat_pid_t pid,
struct iovec iovstack_r[UIO_FASTIOV];
struct iovec *iov_l = iovstack_l;
struct iovec *iov_r = iovstack_r;
struct iov_iter iter;
ssize_t rc = -EFAULT;
if (flags != 0)
@ -439,14 +341,14 @@ 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);
rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,
UIO_FASTIOV, iovstack_r,
&iov_r);
if (rc <= 0)
goto free_iovecs;
rc = process_vm_rw_core(pid, iov_l, liovcnt, iov_r, riovcnt, flags,
vm_write);
rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
free_iovecs:
if (iov_r != iovstack_r)

79
mm/shmem.c
View file

@ -1402,13 +1402,25 @@ shmem_write_end(struct file *file, struct address_space *mapping,
return copied;
}
static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
static ssize_t shmem_file_aio_read(struct kiocb *iocb,
const struct iovec *iov, unsigned long nr_segs, loff_t pos)
{
struct inode *inode = file_inode(filp);
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct address_space *mapping = inode->i_mapping;
pgoff_t index;
unsigned long offset;
enum sgp_type sgp = SGP_READ;
int error;
ssize_t retval;
size_t count;
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
@ -1436,10 +1448,10 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
break;
}
desc->error = shmem_getpage(inode, index, &page, sgp, NULL);
if (desc->error) {
if (desc->error == -EINVAL)
desc->error = 0;
error = shmem_getpage(inode, index, &page, sgp, NULL);
if (error) {
if (error == -EINVAL)
error = 0;
break;
}
if (page)
@ -1483,61 +1495,26 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
/*
* Ok, we have the page, and it's up-to-date, so
* now we can copy it to user space...
*
* The actor routine returns how many bytes were actually used..
* NOTE! This may not be the same as how much of a user buffer
* we filled up (we may be padding etc), so we can only update
* "pos" here (the actor routine has to update the user buffer
* pointers and the remaining count).
*/
ret = actor(desc, page, offset, nr);
ret = copy_page_to_iter(page, offset, nr, &iter);
retval += ret;
offset += ret;
index += offset >> PAGE_CACHE_SHIFT;
offset &= ~PAGE_CACHE_MASK;
page_cache_release(page);
if (ret != nr || !desc->count)
if (!iov_iter_count(&iter))
break;
if (ret < nr) {
error = -EFAULT;
break;
}
cond_resched();
}
*ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
file_accessed(filp);
}
static ssize_t shmem_file_aio_read(struct kiocb *iocb,
const struct iovec *iov, unsigned long nr_segs, loff_t pos)
{
struct file *filp = iocb->ki_filp;
ssize_t retval;
unsigned long seg;
size_t count;
loff_t *ppos = &iocb->ki_pos;
retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
if (retval)
return retval;
for (seg = 0; seg < nr_segs; seg++) {
read_descriptor_t desc;
desc.written = 0;
desc.arg.buf = iov[seg].iov_base;
desc.count = iov[seg].iov_len;
if (desc.count == 0)
continue;
desc.error = 0;
do_shmem_file_read(filp, ppos, &desc, file_read_actor);
retval += desc.written;
if (desc.error) {
retval = retval ?: desc.error;
break;
}
if (desc.count > 0)
break;
}
return retval;
file_accessed(file);
return retval ? retval : error;
}
static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
@ -1576,7 +1553,7 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
index = *ppos >> PAGE_CACHE_SHIFT;
loff = *ppos & ~PAGE_CACHE_MASK;
req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
nr_pages = min(req_pages, pipe->buffers);
nr_pages = min(req_pages, spd.nr_pages_max);
spd.nr_pages = find_get_pages_contig(mapping, index,
nr_pages, spd.pages);