[Patch] encapsulate shmem access to shmem_inode_info

Christoph Rohland
2001-05-04T19:40:32Z

Hi,

On 24 Apr 2001, Christoph Rohland wrote:
> Hi Al,
>
> On Tue, 24 Apr 2001, Alexander Viro wrote:
>> So yes, IMO having such patches available _is_ a good thing. And in
>> 2.5 we definitely want them in the tree. If encapsulation part gets
>> there during 2.4 and separate allocation is available for all of
>> them it will be easier to do without PITA in process.
>
> OK I will do that for tmpfs soon. And I will do the symlink inlining
> with that patch.

Here comes the patch to encapsulate all accesses to struct
shmem_inode_info into a macro. It is now trivial to allocate the
private part independently from the inode.

Greetings
Christoph

P.S: The symlink inlining will come in a separate patch

diff -uNr 2.4.4-mmap_write/include/linux/shmem_fs.h 2.4.4-mmap_write-SHMEM_I/include/linux/shmem_fs.h
--- 2.4.4-mmap_write/include/linux/shmem_fs.h Tue May 1 20:02:00 2001
+++ 2.4.4-mmap_write-SHMEM_I/include/linux/shmem_fs.h Tue May 1 20:06:10 2001
@@ -18,14 +18,15 @@
} swp_entry_t;

struct shmem_inode_info {
- spinlock_t lock;
- struct semaphore sem;
- unsigned long max_index;
- swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* for the first blocks */
- swp_entry_t **i_indirect; /* doubly indirect blocks */
- unsigned long swapped;
- int locked; /* into memory */
+ spinlock_t lock;
+ struct semaphore sem;
+ unsigned long max_index;
+ swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* for the first blocks */
+ swp_entry_t **i_indirect; /* doubly indirect blocks */
+ unsigned long swapped;
+ int locked; /* into memory */
struct list_head list;
+ struct inode *inode;
};

struct shmem_sb_info {
@@ -35,5 +36,7 @@
unsigned long free_inodes; /* How many are left for allocation */
spinlock_t stat_lock;
};
+
+#define SHMEM_I(inode) (&inode->u.shmem_i)

#endif
diff -uNr 2.4.4-mmap_write/ipc/shm.c 2.4.4-mmap_write-SHMEM_I/ipc/shm.c
--- 2.4.4-mmap_write/ipc/shm.c Wed Apr 11 12:36:47 2001
+++ 2.4.4-mmap_write-SHMEM_I/ipc/shm.c Tue May 1 20:06:10 2001
@@ -348,6 +348,7 @@

static void shm_get_stat (unsigned long *rss, unsigned long *swp)
{
+ struct shmem_inode_info *info;
int i;

*rss = 0;
@@ -361,10 +362,11 @@
if(shp == NULL)
continue;
inode = shp->shm_file->f_dentry->d_inode;
- spin_lock (&inode->u.shmem_i.lock);
+ info = SHMEM_I(inode);
+ spin_lock (&info->lock);
*rss += inode->i_mapping->nrpages;
- *swp += inode->u.shmem_i.swapped;
- spin_unlock (&inode->u.shmem_i.lock);
+ *swp += info->swapped;
+ spin_unlock (&info->lock);
}
}

diff -uNr 2.4.4-mmap_write/mm/shmem.c 2.4.4-mmap_write-SHMEM_I/mm/shmem.c
--- 2.4.4-mmap_write/mm/shmem.c Tue May 1 20:02:00 2001
+++ 2.4.4-mmap_write-SHMEM_I/mm/shmem.c Wed May 2 16:46:00 2001
@@ -73,7 +73,7 @@
unsigned long freed;

freed = (inode->i_blocks/BLOCKS_PER_PAGE) -
- (inode->i_mapping->nrpages + inode->u.shmem_i.swapped);
+ (inode->i_mapping->nrpages + SHMEM_I(inode)->swapped);
if (freed){
struct shmem_sb_info * info = &inode->i_sb->u.shmem_sb;
inode->i_blocks -= freed*BLOCKS_PER_PAGE;
@@ -159,7 +159,7 @@
unsigned long index, start;
unsigned long freed = 0;
swp_entry_t **base, **ptr, **last;
- struct shmem_inode_info * info = &inode->u.shmem_i;
+ struct shmem_inode_info * info = SHMEM_I(inode);

down(&info->sem);
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
@@ -206,7 +206,7 @@
struct shmem_sb_info *info = &inode->i_sb->u.shmem_sb;

spin_lock (&shmem_ilock);
- list_del (&inode->u.shmem_i.list);
+ list_del (&SHMEM_I(inode)->list);
spin_unlock (&shmem_ilock);
inode->i_size = 0;
shmem_truncate (inode);
@@ -239,7 +239,7 @@
goto out;

inode = page->mapping->host;
- info = &inode->u.shmem_i;
+ info = SHMEM_I(inode);
swap = __get_swap_page(2);
error = -ENOMEM;
if (!swap.val)
@@ -407,7 +407,7 @@
page_cache_release(*ptr);
}

- info = &inode->u.shmem_i;
+ info = SHMEM_I(inode);
down (&info->sem);
/* retest we may have slept */

@@ -415,7 +415,7 @@
if (inode->i_size < (loff_t) idx * PAGE_CACHE_SIZE)
goto failed;

- *ptr = shmem_getpage_locked(&inode->u.shmem_i, inode, idx);
+ *ptr = shmem_getpage_locked(info, inode, idx);
if (IS_ERR (*ptr))
goto failed;

@@ -462,7 +462,7 @@
void shmem_lock(struct file * file, int lock)
{
struct inode * inode = file->f_dentry->d_inode;
- struct shmem_inode_info * info = &inode->u.shmem_i;
+ struct shmem_inode_info * info = SHMEM_I(inode);
struct page * page;
unsigned long idx, size;

@@ -521,7 +521,8 @@
inode->i_rdev = to_kdev_t(dev);
inode->i_mapping->a_ops = &shmem_aops;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
- info = &inode->u.shmem_i;
+ info = SHMEM_I(inode);
+ info->inode = inode;
spin_lock_init (&info->lock);
sema_init (&info->sem, 1);
switch (mode & S_IFMT) {
@@ -542,7 +543,7 @@
break;
}
spin_lock (&shmem_ilock);
- list_add (&inode->u.shmem_i.list, &shmem_inodes);
+ list_add (&SHMEM_I(inode)->list, &shmem_inodes);
spin_unlock (&shmem_ilock);
}
return inode;
@@ -629,7 +630,7 @@
__get_user(dummy, buf+bytes-1);
}

- info = &inode->u.shmem_i;
+ info = SHMEM_I(inode);
down (&info->sem);
page = shmem_getpage_locked(info, inode, index);
up (&info->sem);
@@ -658,8 +659,8 @@
buf += bytes;
if (pos > inode->i_size)
inode->i_size = pos;
- if (inode->u.shmem_i.max_index <= index)
- inode->u.shmem_i.max_index = index+1;
+ if (info->max_index <= index)
+ info->max_index = index+1;

}
unlock:
@@ -940,7 +941,7 @@

inode = dentry->d_inode;
down(&inode->i_sem);
- page = shmem_getpage_locked(&inode->u.shmem_i, inode, 0);
+ page = shmem_getpage_locked(SHMEM_I(inode), inode, 0);
if (IS_ERR(page))
goto fail;
kaddr = kmap(page);
@@ -1220,12 +1221,11 @@
return -1;
}

-static int shmem_unuse_inode (struct inode *inode, swp_entry_t entry, struct page *page)
+static int shmem_unuse_inode (struct shmem_inode_info *info, swp_entry_t entry, struct page *page)
{
swp_entry_t **base, **ptr;
unsigned long idx;
int offset;
- struct shmem_inode_info *info = &inode->u.shmem_i;

idx = 0;
spin_lock (&info->lock);
@@ -1246,7 +1246,7 @@
spin_unlock (&info->lock);
return 0;
found:
- add_to_page_cache(page, inode->i_mapping, offset + idx);
+ add_to_page_cache(page, info->inode->i_mapping, offset + idx);
set_page_dirty(page);
SetPageUptodate(page);
UnlockPage(page);
@@ -1261,13 +1261,13 @@
void shmem_unuse(swp_entry_t entry, struct page *page)
{
struct list_head *p;
- struct inode * inode;
+ struct shmem_inode_info * info;

spin_lock (&shmem_ilock);
list_for_each(p, &shmem_inodes) {
- inode = list_entry(p, struct inode, u.shmem_i.list);
+ info = list_entry(p, struct shmem_inode_info, list);

- if (shmem_unuse_inode(inode, entry, page))
+ if (shmem_unuse_inode(info, entry, page))
break;
}
spin_unlock (&shmem_ilock);