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[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>
This commit is contained in:
Carsten Otte 2005-06-23 22:05:28 -07:00 committed by Linus Torvalds
parent 6d79125bba
commit eb6fe0c388
4 changed files with 65 additions and 207 deletions
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8
fs/ext2/file.c
View File

@ -58,17 +58,13 @@ struct file_operations ext2_file_operations = {
#ifdef CONFIG_EXT2_FS_XIP
struct file_operations ext2_xip_file_operations = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = xip_file_aio_read,
.aio_write = xip_file_aio_write,
.read = xip_file_read,
.write = xip_file_write,
.ioctl = ext2_ioctl,
.mmap = xip_file_mmap,
.open = generic_file_open,
.release = ext2_release_file,
.fsync = ext2_sync_file,
.readv = xip_file_readv,
.writev = xip_file_writev,
.sendfile = xip_file_sendfile,
};
#endif

12
include/linux/fs.h
View File

@ -1500,18 +1500,14 @@ extern int generic_file_open(struct inode * inode, struct file * filp);
extern int nonseekable_open(struct inode * inode, struct file * filp);
#ifdef CONFIG_FS_XIP
extern ssize_t xip_file_aio_read(struct kiocb *iocb, char __user *buf,
size_t count, loff_t pos);
extern ssize_t xip_file_readv(struct file *filp, const struct iovec *iov,
unsigned long nr_segs, loff_t *ppos);
extern ssize_t xip_file_read(struct file *filp, char __user *buf, size_t len,
loff_t *ppos);
extern ssize_t xip_file_sendfile(struct file *in_file, loff_t *ppos,
size_t count, read_actor_t actor,
void *target);
extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
extern ssize_t xip_file_aio_write(struct kiocb *iocb, const char __user *buf,
size_t count, loff_t pos);
extern ssize_t xip_file_writev(struct file *file, const struct iovec *iov,
unsigned long nr_segs, loff_t *ppos);
extern ssize_t xip_file_write(struct file *filp, const char __user *buf,
size_t len, loff_t *ppos);
extern int xip_truncate_page(struct address_space *mapping, loff_t from);
#else
static inline int xip_truncate_page(struct address_space *mapping, loff_t from)

2
mm/filemap.h
View File

@ -15,7 +15,7 @@
#include <linux/config.h>
#include <asm/uaccess.h>
extern size_t
size_t
__filemap_copy_from_user_iovec(char *vaddr,
const struct iovec *iov,
size_t base,

250
mm/filemap_xip.c
View File

@ -114,83 +114,28 @@ out:
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 @@ int xip_file_mmap(struct file * file, struct vm_area_struct * vma)
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 @@ do_xip_file_write(struct kiocb *iocb, const struct iovec *iov,
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 @@ do_xip_file_write(struct kiocb *iocb, const struct iovec *iov,
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 @@ do_xip_file_write(struct kiocb *iocb, const struct iovec *iov,
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 @@ do_xip_file_write(struct kiocb *iocb, const struct iovec *iov,
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;
err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
if (err)
goto out;
/* We can write back this queue in page reclaim */
current->backing_dev_info = mapping->backing_dev_info;
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 @@ xip_truncate_page(struct address_space *mapping, loff_t from)
unsigned length;
struct page *page;
void *kaddr;
int err;
BUG_ON(!mapping->a_ops->get_xip_page);
@ -556,17 +427,14 @@ xip_truncate_page(struct address_space *mapping, loff_t from)
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 @@ xip_truncate_page(struct address_space *mapping, loff_t from)
kunmap_atomic(kaddr, KM_USER0);
flush_dcache_page(page);
err = 0;
out:
return err;
return 0;
}
EXPORT_SYMBOL_GPL(xip_truncate_page);