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-rw-r--r--mm/shmem.c110
1 files changed, 89 insertions, 21 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 0ed075215e5..5d0de96c978 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -14,31 +14,39 @@
* Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
* Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
*
+ * tiny-shmem:
+ * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com>
+ *
* This file is released under the GPL.
*/
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/vfs.h>
+#include <linux/mount.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/swap.h>
+
+static struct vfsmount *shm_mnt;
+
+#ifdef CONFIG_SHMEM
/*
* This virtual memory filesystem is heavily based on the ramfs. It
* extends ramfs by the ability to use swap and honor resource limits
* which makes it a completely usable filesystem.
*/
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/fs.h>
#include <linux/xattr.h>
#include <linux/exportfs.h>
#include <linux/generic_acl.h>
-#include <linux/mm.h>
#include <linux/mman.h>
-#include <linux/file.h>
-#include <linux/swap.h>
#include <linux/pagemap.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/backing-dev.h>
#include <linux/shmem_fs.h>
-#include <linux/mount.h>
#include <linux/writeback.h>
#include <linux/vfs.h>
#include <linux/blkdev.h>
@@ -920,7 +928,11 @@ found:
error = 1;
if (!inode)
goto out;
- /* Precharge page using GFP_KERNEL while we can wait */
+ /*
+ * Charge page using GFP_KERNEL while we can wait.
+ * Charged back to the user(not to caller) when swap account is used.
+ * add_to_page_cache() will be called with GFP_NOWAIT.
+ */
error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
if (error)
goto out;
@@ -1312,15 +1324,19 @@ repeat:
} else {
shmem_swp_unmap(entry);
spin_unlock(&info->lock);
- unlock_page(swappage);
- page_cache_release(swappage);
if (error == -ENOMEM) {
/* allow reclaim from this memory cgroup */
- error = mem_cgroup_shrink_usage(current->mm,
+ error = mem_cgroup_shrink_usage(swappage,
+ current->mm,
gfp);
- if (error)
+ if (error) {
+ unlock_page(swappage);
+ page_cache_release(swappage);
goto failed;
+ }
}
+ unlock_page(swappage);
+ page_cache_release(swappage);
goto repeat;
}
} else if (sgp == SGP_READ && !filepage) {
@@ -1371,7 +1387,7 @@ repeat:
/* Precharge page while we can wait, compensate after */
error = mem_cgroup_cache_charge(filepage, current->mm,
- gfp & ~__GFP_HIGHMEM);
+ GFP_KERNEL);
if (error) {
page_cache_release(filepage);
shmem_unacct_blocks(info->flags, 1);
@@ -1444,7 +1460,6 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
if (error)
return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
- mark_page_accessed(vmf->page);
return ret | VM_FAULT_LOCKED;
}
@@ -1513,8 +1528,8 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
inode = new_inode(sb);
if (inode) {
inode->i_mode = mode;
- inode->i_uid = current->fsuid;
- inode->i_gid = current->fsgid;
+ inode->i_uid = current_fsuid();
+ inode->i_gid = current_fsgid();
inode->i_blocks = 0;
inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
@@ -2278,8 +2293,8 @@ static int shmem_fill_super(struct super_block *sb,
sbinfo->max_blocks = 0;
sbinfo->max_inodes = 0;
sbinfo->mode = S_IRWXUGO | S_ISVTX;
- sbinfo->uid = current->fsuid;
- sbinfo->gid = current->fsgid;
+ sbinfo->uid = current_fsuid();
+ sbinfo->gid = current_fsgid();
sbinfo->mpol = NULL;
sb->s_fs_info = sbinfo;
@@ -2486,7 +2501,6 @@ static struct file_system_type tmpfs_fs_type = {
.get_sb = shmem_get_sb,
.kill_sb = kill_litter_super,
};
-static struct vfsmount *shm_mnt;
static int __init init_tmpfs(void)
{
@@ -2525,7 +2539,51 @@ out4:
shm_mnt = ERR_PTR(error);
return error;
}
-module_init(init_tmpfs)
+
+#else /* !CONFIG_SHMEM */
+
+/*
+ * tiny-shmem: simple shmemfs and tmpfs using ramfs code
+ *
+ * This is intended for small system where the benefits of the full
+ * shmem code (swap-backed and resource-limited) are outweighed by
+ * their complexity. On systems without swap this code should be
+ * effectively equivalent, but much lighter weight.
+ */
+
+#include <linux/ramfs.h>
+
+static struct file_system_type tmpfs_fs_type = {
+ .name = "tmpfs",
+ .get_sb = ramfs_get_sb,
+ .kill_sb = kill_litter_super,
+};
+
+static int __init init_tmpfs(void)
+{
+ BUG_ON(register_filesystem(&tmpfs_fs_type) != 0);
+
+ shm_mnt = kern_mount(&tmpfs_fs_type);
+ BUG_ON(IS_ERR(shm_mnt));
+
+ return 0;
+}
+
+int shmem_unuse(swp_entry_t entry, struct page *page)
+{
+ return 0;
+}
+
+#define shmem_file_operations ramfs_file_operations
+#define shmem_vm_ops generic_file_vm_ops
+#define shmem_get_inode ramfs_get_inode
+#define shmem_acct_size(a, b) 0
+#define shmem_unacct_size(a, b) do {} while (0)
+#define SHMEM_MAX_BYTES LLONG_MAX
+
+#endif /* CONFIG_SHMEM */
+
+/* common code */
/**
* shmem_file_setup - get an unlinked file living in tmpfs
@@ -2569,12 +2627,20 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
if (!inode)
goto close_file;
+#ifdef CONFIG_SHMEM
SHMEM_I(inode)->flags = flags & VM_ACCOUNT;
+#endif
d_instantiate(dentry, inode);
inode->i_size = size;
inode->i_nlink = 0; /* It is unlinked */
init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
- &shmem_file_operations);
+ &shmem_file_operations);
+
+#ifndef CONFIG_MMU
+ error = ramfs_nommu_expand_for_mapping(inode, size);
+ if (error)
+ goto close_file;
+#endif
return file;
close_file:
@@ -2606,3 +2672,5 @@ int shmem_zero_setup(struct vm_area_struct *vma)
vma->vm_ops = &shmem_vm_ops;
return 0;
}
+
+module_init(init_tmpfs)
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-01 11:47:00 +0000