[PATCH v4 23/31] nfs: simplify swap
From: Dave Kleikamp
Date: Thu Nov 22 2012 - 14:23:18 EST
swap_writepage can now call nfs's write_iter f_op, eliminating the need to
implement for the special-case direct_IO a_op. There is no longer a need to
pass the uio flag through the direct write path.
Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Cc: linux-nfs@xxxxxxxxxxxxxxx
Cc: Rik van Riel <riel@xxxxxxxxxx>
---
fs/nfs/direct.c | 94 +++++++++++++++++---------------------------------
fs/nfs/file.c | 4 +--
include/linux/nfs_fs.h | 4 +--
mm/page_io.c | 13 ++++---
4 files changed, 42 insertions(+), 73 deletions(-)
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 6754588..b8be1e1 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -118,29 +118,18 @@ static inline int put_dreq(struct nfs_direct_req *dreq)
* @nr_segs: size of iovec array
*
* The presence of this routine in the address space ops vector means
- * the NFS client supports direct I/O. However, for most direct IO, we
- * shunt off direct read and write requests before the VFS gets them,
- * so this method is only ever called for swap.
+ * the NFS client supports direct I/O. However, we shunt off direct
+ * read and write requests before the VFS gets them, so this method
+ * should never be called.
*/
ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
loff_t pos)
{
-#ifndef CONFIG_NFS_SWAP
dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n",
iocb->ki_filp->f_path.dentry->d_name.name,
(long long) pos, iter->nr_segs);
return -EINVAL;
-#else
- VM_BUG_ON(iocb->ki_left != PAGE_SIZE);
- VM_BUG_ON(iocb->ki_nbytes != PAGE_SIZE);
-
- if (rw == READ || rw == KERNEL_READ)
- return nfs_file_direct_read(iocb, iter, pos,
- rw == READ ? true : false);
- return nfs_file_direct_write(iocb, iter, pos,
- rw == WRITE ? true : false);
-#endif /* CONFIG_NFS_SWAP */
}
static void nfs_direct_release_pages(struct page **pages, unsigned int npages)
@@ -325,7 +314,7 @@ static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = {
*/
static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *desc,
const struct iovec *iov,
- loff_t pos, bool uio)
+ loff_t pos)
{
struct nfs_direct_req *dreq = desc->pg_dreq;
struct nfs_open_context *ctx = dreq->ctx;
@@ -353,20 +342,12 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *de
GFP_KERNEL);
if (!pagevec)
break;
- if (uio) {
- down_read(¤t->mm->mmap_sem);
- result = get_user_pages(current, current->mm, user_addr,
+ down_read(¤t->mm->mmap_sem);
+ result = get_user_pages(current, current->mm, user_addr,
npages, 1, 0, pagevec, NULL);
- up_read(¤t->mm->mmap_sem);
- if (result < 0)
- break;
- } else {
- WARN_ON(npages != 1);
- result = get_kernel_page(user_addr, 1, pagevec);
- if (WARN_ON(result != 1))
- break;
- }
-
+ up_read(¤t->mm->mmap_sem);
+ if (result < 0)
+ break;
if ((unsigned)result < npages) {
bytes = result * PAGE_SIZE;
if (bytes <= pgbase) {
@@ -416,7 +397,7 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *de
static ssize_t nfs_direct_do_schedule_read_iovec(
struct nfs_pageio_descriptor *desc, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos, bool uio)
+ unsigned long nr_segs, loff_t pos)
{
ssize_t result = -EINVAL;
size_t requested_bytes = 0;
@@ -424,7 +405,7 @@ static ssize_t nfs_direct_do_schedule_read_iovec(
for (seg = 0; seg < nr_segs; seg++) {
const struct iovec *vec = &iov[seg];
- result = nfs_direct_read_schedule_segment(desc, vec, pos, uio);
+ result = nfs_direct_read_schedule_segment(desc, vec, pos);
if (result < 0)
break;
requested_bytes += result;
@@ -479,8 +460,7 @@ static ssize_t nfs_direct_do_schedule_read_bvec(
}
static ssize_t nfs_direct_read_schedule(struct nfs_direct_req *dreq,
- struct iov_iter *iter, loff_t pos,
- bool uio)
+ struct iov_iter *iter, loff_t pos)
{
struct nfs_pageio_descriptor desc;
ssize_t result;
@@ -491,10 +471,8 @@ static ssize_t nfs_direct_read_schedule(struct nfs_direct_req *dreq,
desc.pg_dreq = dreq;
if (iov_iter_has_iovec(iter)) {
- if (uio)
- dreq->flags = NFS_ODIRECT_MARK_DIRTY;
result = nfs_direct_do_schedule_read_iovec(&desc,
- iov_iter_iovec(iter), iter->nr_segs, pos, uio);
+ iov_iter_iovec(iter), iter->nr_segs, pos);
} else if (iov_iter_has_bvec(iter)) {
result = nfs_direct_do_schedule_read_bvec(&desc,
iov_iter_bvec(iter), iter->nr_segs, pos);
@@ -518,7 +496,7 @@ static ssize_t nfs_direct_read_schedule(struct nfs_direct_req *dreq,
}
static ssize_t nfs_direct_read(struct kiocb *iocb, struct iov_iter *iter,
- loff_t pos, bool uio)
+ loff_t pos)
{
ssize_t result = -ENOMEM;
struct inode *inode = iocb->ki_filp->f_mapping->host;
@@ -542,7 +520,7 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, struct iov_iter *iter,
dreq->iocb = iocb;
NFS_I(inode)->read_io += iov_iter_count(iter);
- result = nfs_direct_read_schedule(dreq, iter, pos, uio);
+ result = nfs_direct_read_schedule(dreq, iter, pos);
if (!result)
result = nfs_direct_wait(dreq);
out_release:
@@ -707,7 +685,7 @@ static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode
*/
static ssize_t nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor *desc,
const struct iovec *iov,
- loff_t pos, bool uio)
+ loff_t pos)
{
struct nfs_direct_req *dreq = desc->pg_dreq;
struct nfs_open_context *ctx = dreq->ctx;
@@ -735,19 +713,12 @@ static ssize_t nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor *d
if (!pagevec)
break;
- if (uio) {
- down_read(¤t->mm->mmap_sem);
- result = get_user_pages(current, current->mm, user_addr,
- npages, 0, 0, pagevec, NULL);
- up_read(¤t->mm->mmap_sem);
- if (result < 0)
- break;
- } else {
- WARN_ON(npages != 1);
- result = get_kernel_page(user_addr, 0, pagevec);
- if (WARN_ON(result != 1))
- break;
- }
+ down_read(¤t->mm->mmap_sem);
+ result = get_user_pages(current, current->mm, user_addr,
+ npages, 0, 0, pagevec, NULL);
+ up_read(¤t->mm->mmap_sem);
+ if (result < 0)
+ break;
if ((unsigned)result < npages) {
bytes = result * PAGE_SIZE;
@@ -878,7 +849,7 @@ static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = {
static ssize_t nfs_direct_do_schedule_write_iovec(
struct nfs_pageio_descriptor *desc, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos, bool uio)
+ unsigned long nr_segs, loff_t pos)
{
ssize_t result = -EINVAL;
size_t requested_bytes = 0;
@@ -887,7 +858,7 @@ static ssize_t nfs_direct_do_schedule_write_iovec(
for (seg = 0; seg < nr_segs; seg++) {
const struct iovec *vec = &iov[seg];
result = nfs_direct_write_schedule_segment(desc, vec,
- pos, uio);
+ pos);
if (result < 0)
break;
requested_bytes += result;
@@ -943,8 +914,7 @@ static ssize_t nfs_direct_do_schedule_write_bvec(
}
static ssize_t nfs_direct_write_schedule(struct nfs_direct_req *dreq,
- struct iov_iter *iter, loff_t pos,
- bool uio)
+ struct iov_iter *iter, loff_t pos)
{
struct nfs_pageio_descriptor desc;
struct inode *inode = dreq->inode;
@@ -960,7 +930,7 @@ static ssize_t nfs_direct_write_schedule(struct nfs_direct_req *dreq,
if (iov_iter_has_iovec(iter)) {
result = nfs_direct_do_schedule_write_iovec(&desc,
- iov_iter_iovec(iter), iter->nr_segs, pos, uio);
+ iov_iter_iovec(iter), iter->nr_segs, pos);
} else if (iov_iter_has_bvec(iter)) {
result = nfs_direct_do_schedule_write_bvec(&desc,
iov_iter_bvec(iter), iter->nr_segs, pos);
@@ -985,7 +955,7 @@ static ssize_t nfs_direct_write_schedule(struct nfs_direct_req *dreq,
}
static ssize_t nfs_direct_write(struct kiocb *iocb, struct iov_iter *iter,
- loff_t pos, bool uio)
+ loff_t pos)
{
ssize_t result = -ENOMEM;
struct inode *inode = iocb->ki_filp->f_mapping->host;
@@ -1008,7 +978,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, struct iov_iter *iter,
if (!is_sync_kiocb(iocb))
dreq->iocb = iocb;
- result = nfs_direct_write_schedule(dreq, iter, pos, uio);
+ result = nfs_direct_write_schedule(dreq, iter, pos);
if (!result)
result = nfs_direct_wait(dreq);
out_release:
@@ -1038,7 +1008,7 @@ out:
* cache.
*/
ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
- loff_t pos, bool uio)
+ loff_t pos)
{
ssize_t retval = -EINVAL;
struct file *file = iocb->ki_filp;
@@ -1063,7 +1033,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
task_io_account_read(count);
- retval = nfs_direct_read(iocb, iter, pos, uio);
+ retval = nfs_direct_read(iocb, iter, pos);
if (retval > 0)
iocb->ki_pos = pos + retval;
@@ -1093,7 +1063,7 @@ out:
* is no atomic O_APPEND write facility in the NFS protocol.
*/
ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter,
- loff_t pos, bool uio)
+ loff_t pos)
{
ssize_t retval = -EINVAL;
struct file *file = iocb->ki_filp;
@@ -1125,7 +1095,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter,
task_io_account_write(count);
- retval = nfs_direct_write(iocb, iter, pos, uio);
+ retval = nfs_direct_write(iocb, iter, pos);
if (retval > 0) {
struct inode *inode = mapping->host;
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 1b7d325..b93f44f 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -179,7 +179,7 @@ nfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
ssize_t result;
if (iocb->ki_filp->f_flags & O_DIRECT)
- return nfs_file_direct_read(iocb, iter, pos, true);
+ return nfs_file_direct_read(iocb, iter, pos);
dprintk("NFS: read_iter(%s/%s, %lu@%lu)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
@@ -619,7 +619,7 @@ ssize_t nfs_file_write_iter(struct kiocb *iocb, struct iov_iter *iter,
size_t count = iov_iter_count(iter);
if (iocb->ki_filp->f_flags & O_DIRECT)
- return nfs_file_direct_write(iocb, iter, pos, true);
+ return nfs_file_direct_write(iocb, iter, pos);
dprintk("NFS: write_iter(%s/%s, %lu@%lld)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 9f8e8a9..6033367 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -446,9 +446,9 @@ extern int nfs3_removexattr (struct dentry *, const char *name);
*/
extern ssize_t nfs_direct_IO(int, struct kiocb *, struct iov_iter *, loff_t);
extern ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
- loff_t pos, bool uio);
+ loff_t pos);
extern ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter,
- loff_t pos, bool uio);
+ loff_t pos);
/*
* linux/fs/nfs/dir.c
diff --git a/mm/page_io.c b/mm/page_io.c
index 33da274..60a5503 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -203,14 +203,14 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
if (sis->flags & SWP_FILE) {
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 bvec = {
+ .bv_page = kmap(page),
+ .bv_len = PAGE_SIZE,
+ .bv_offset = 0,
};
struct iov_iter iter;
- iov_iter_init(&iter, &iov, 1, PAGE_SIZE, 0);
+ iov_iter_init_bvec(&iter, &bvec, 1, PAGE_SIZE, 0);
init_sync_kiocb(&kiocb, swap_file);
kiocb.ki_pos = page_file_offset(page);
@@ -218,8 +218,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
kiocb.ki_nbytes = PAGE_SIZE;
unlock_page(page);
- ret = mapping->a_ops->direct_IO(KERNEL_WRITE, &kiocb, &iter,
- kiocb.ki_pos);
+ ret = swap_file->f_op->write_iter(&kiocb, &iter, kiocb.ki_pos);
kunmap(page);
if (ret == PAGE_SIZE) {
count_vm_event(PSWPOUT);
--
1.8.0
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/