[PATCH] xip: reduce code duplication
This patch reworks filemap_xip.c with the goal to reduce code duplication
from mm/filemap.c. It applies agains 2.6.12-rc6-mm1. Instead of
implementing the aio functions, this one implements the synchronous
read/write functions only. For readv and writev, the generic fallback is
used. For aio, we rely on the application doing the fallback. Since our
"synchronous" function does memcpy immediately anyway, there is no
performance difference between using the fallbacks or implementing each
operation.
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 7d63acd..3b6e384 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -114,83 +114,28 @@
file_accessed(filp);
}
-/*
- * This is the "read()" routine for all filesystems
- * that uses the get_xip_page address space operation.
- */
-static ssize_t
-__xip_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t *ppos)
-{
- struct file *filp = iocb->ki_filp;
- ssize_t retval;
- unsigned long seg;
- size_t count;
-
- count = 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.
- */
- count += iv->iov_len;
- if (unlikely((ssize_t)(count|iv->iov_len) < 0))
- return -EINVAL;
- if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len))
- continue;
- if (seg == 0)
- return -EFAULT;
- nr_segs = seg;
- count -= iv->iov_len; /* This segment is no good */
- break;
- }
-
- retval = 0;
- if (count) {
- 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_xip_mapping_read(filp->f_mapping, &filp->f_ra, filp,
- ppos, &desc, file_read_actor);
- retval += desc.written;
- if (!retval) {
- retval = desc.error;
- break;
- }
- }
- }
- return retval;
-}
-
ssize_t
-xip_file_aio_read(struct kiocb *iocb, char __user *buf, size_t count,
- loff_t pos)
+xip_file_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
- struct iovec local_iov = { .iov_base = buf, .iov_len = count };
+ read_descriptor_t desc;
- BUG_ON(iocb->ki_pos != pos);
- return __xip_file_aio_read(iocb, &local_iov, 1, &iocb->ki_pos);
+ if (!access_ok(VERIFY_WRITE, buf, len))
+ return -EFAULT;
+
+ desc.written = 0;
+ desc.arg.buf = buf;
+ desc.count = len;
+ desc.error = 0;
+
+ do_xip_mapping_read(filp->f_mapping, &filp->f_ra, filp,
+ ppos, &desc, file_read_actor);
+
+ if (desc.written)
+ return desc.written;
+ else
+ return desc.error;
}
-EXPORT_SYMBOL_GPL(xip_file_aio_read);
-
-ssize_t
-xip_file_readv(struct file *filp, const struct iovec *iov,
- unsigned long nr_segs, loff_t *ppos)
-{
- struct kiocb kiocb;
-
- init_sync_kiocb(&kiocb, filp);
- return __xip_file_aio_read(&kiocb, iov, nr_segs, ppos);
-}
-EXPORT_SYMBOL_GPL(xip_file_readv);
+EXPORT_SYMBOL_GPL(xip_file_read);
ssize_t
xip_file_sendfile(struct file *in_file, loff_t *ppos,
@@ -326,25 +271,19 @@
EXPORT_SYMBOL_GPL(xip_file_mmap);
static ssize_t
-do_xip_file_write(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos, loff_t *ppos,
- size_t count)
+__xip_file_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t pos, loff_t *ppos)
{
- struct file *file = iocb->ki_filp;
- struct address_space * mapping = file->f_mapping;
+ struct address_space * mapping = filp->f_mapping;
struct address_space_operations *a_ops = mapping->a_ops;
struct inode *inode = mapping->host;
long status = 0;
struct page *page;
size_t bytes;
- const struct iovec *cur_iov = iov; /* current iovec */
- size_t iov_base = 0; /* offset in the current iovec */
- char __user *buf;
ssize_t written = 0;
BUG_ON(!mapping->a_ops->get_xip_page);
- buf = iov->iov_base;
do {
unsigned long index;
unsigned long offset;
@@ -365,15 +304,14 @@
fault_in_pages_readable(buf, bytes);
page = a_ops->get_xip_page(mapping,
- index*(PAGE_SIZE/512), 0);
+ index*(PAGE_SIZE/512), 0);
if (IS_ERR(page) && (PTR_ERR(page) == -ENODATA)) {
/* we allocate a new page unmap it */
page = a_ops->get_xip_page(mapping,
- index*(PAGE_SIZE/512), 1);
+ index*(PAGE_SIZE/512), 1);
if (!IS_ERR(page))
- /* unmap page at pgoff from all other vmas */
- __xip_unmap(mapping, index);
-
+ /* unmap page at pgoff from all other vmas */
+ __xip_unmap(mapping, index);
}
if (IS_ERR(page)) {
@@ -383,12 +321,7 @@
BUG_ON(!PageUptodate(page));
- if (likely(nr_segs == 1))
- copied = filemap_copy_from_user(page, offset,
- buf, bytes);
- else
- copied = filemap_copy_from_user_iovec(page, offset,
- cur_iov, iov_base, bytes);
+ copied = filemap_copy_from_user(page, offset, buf, bytes);
flush_dcache_page(page);
if (likely(copied > 0)) {
status = copied;
@@ -398,9 +331,6 @@
count -= status;
pos += status;
buf += status;
- if (unlikely(nr_segs > 1))
- filemap_set_next_iovec(&cur_iov,
- &iov_base, status);
}
}
if (unlikely(copied != bytes))
@@ -422,110 +352,52 @@
return written ? written : status;
}
-static ssize_t
-xip_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t *ppos)
+ssize_t
+xip_file_write(struct file *filp, const char __user *buf, size_t len,
+ loff_t *ppos)
{
- 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;
- unsigned long seg;
- loff_t pos;
- ssize_t written;
- ssize_t err;
+ struct address_space *mapping = filp->f_mapping;
+ struct inode *inode = mapping->host;
+ size_t count;
+ loff_t pos;
+ ssize_t ret;
- ocount = 0;
- for (seg = 0; seg < nr_segs; seg++) {
- const struct iovec *iv = &iov[seg];
+ down(&inode->i_sem);
- /*
- * If any segment has a negative length, or the cumulative
- * length ever wraps negative then return -EINVAL.
- */
- ocount += iv->iov_len;
- if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
- return -EINVAL;
- if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
- continue;
- if (seg == 0)
- return -EFAULT;
- nr_segs = seg;
- ocount -= iv->iov_len; /* This segment is no good */
- break;
+ if (!access_ok(VERIFY_READ, buf, len)) {
+ ret=-EFAULT;
+ goto out_up;
}
- count = ocount;
pos = *ppos;
+ count = len;
vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
- written = 0;
+ /* We can write back this queue in page reclaim */
+ current->backing_dev_info = mapping->backing_dev_info;
- err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
- if (err)
- goto out;
-
+ ret = generic_write_checks(filp, &pos, &count, S_ISBLK(inode->i_mode));
+ if (ret)
+ goto out_backing;
if (count == 0)
- goto out;
+ goto out_backing;
- err = remove_suid(file->f_dentry);
- if (err)
- goto out;
+ ret = remove_suid(filp->f_dentry);
+ if (ret)
+ goto out_backing;
inode_update_time(inode, 1);
- /* use execute in place to copy directly to disk */
- written = do_xip_file_write (iocb, iov,
- nr_segs, pos, ppos, count);
- out:
- return written ? written : err;
-}
+ ret = __xip_file_write (filp, buf, count, pos, ppos);
-static ssize_t
-__xip_file_write_nolock(struct file *file, const struct iovec *iov,
- unsigned long nr_segs, loff_t *ppos)
-{
- struct kiocb kiocb;
-
- init_sync_kiocb(&kiocb, file);
- return xip_file_aio_write_nolock(&kiocb, iov, nr_segs, ppos);
-}
-
-ssize_t
-xip_file_aio_write(struct kiocb *iocb, const char __user *buf,
- size_t count, loff_t pos)
-{
- struct file *file = iocb->ki_filp;
- struct address_space *mapping = file->f_mapping;
- struct inode *inode = mapping->host;
- ssize_t ret;
- struct iovec local_iov = { .iov_base = (void __user *)buf,
- .iov_len = count };
-
- BUG_ON(iocb->ki_pos != pos);
-
- down(&inode->i_sem);
- ret = xip_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
+ out_backing:
+ current->backing_dev_info = NULL;
+ out_up:
up(&inode->i_sem);
return ret;
}
-EXPORT_SYMBOL_GPL(xip_file_aio_write);
-
-ssize_t xip_file_writev(struct file *file, const struct iovec *iov,
- unsigned long nr_segs, loff_t *ppos)
-{
- struct address_space *mapping = file->f_mapping;
- struct inode *inode = mapping->host;
- ssize_t ret;
-
- down(&inode->i_sem);
- ret = __xip_file_write_nolock(file, iov, nr_segs, ppos);
- up(&inode->i_sem);
- return ret;
-}
-EXPORT_SYMBOL_GPL(xip_file_writev);
+EXPORT_SYMBOL_GPL(xip_file_write);
/*
* truncate a page used for execute in place
@@ -541,7 +413,6 @@
unsigned length;
struct page *page;
void *kaddr;
- int err;
BUG_ON(!mapping->a_ops->get_xip_page);
@@ -556,17 +427,14 @@
page = mapping->a_ops->get_xip_page(mapping,
index*(PAGE_SIZE/512), 0);
- err = -ENOMEM;
if (!page)
- goto out;
+ return -ENOMEM;
if (unlikely(IS_ERR(page))) {
- if (PTR_ERR(page) == -ENODATA) {
+ if (PTR_ERR(page) == -ENODATA)
/* Hole? No need to truncate */
return 0;
- } else {
- err = PTR_ERR(page);
- goto out;
- }
+ else
+ return PTR_ERR(page);
} else
BUG_ON(!PageUptodate(page));
kaddr = kmap_atomic(page, KM_USER0);
@@ -574,8 +442,6 @@
kunmap_atomic(kaddr, KM_USER0);
flush_dcache_page(page);
- err = 0;
-out:
- return err;
+ return 0;
}
EXPORT_SYMBOL_GPL(xip_truncate_page);
