KVM: Remove kvmfs in favor of the anonymous inodes source

kvm uses a pseudo filesystem, kvmfs, to generate inodes, a job that the
new anonymous inodes source does much better.

Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 5603000573ec0bbcd6018970585ed6990760d58c..26ca90f74fc7f6de0b3e17357a22c2eca1fc4f05 100644 (file)
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -43,6 +43,7 @@
 #include <linux/sched.h>
 #include <linux/cpumask.h>
 #include <linux/smp.h>
+#include <linux/anon_inodes.h>
 
 #include "x86_emulate.h"
 #include "segment_descriptor.h"
@@ -81,8 +82,6 @@ static struct kvm_stats_debugfs_item {
 
 static struct dentry *debugfs_dir;
 
-struct vfsmount *kvmfs_mnt;
-
 #define MAX_IO_MSRS 256
 
 #define CR0_RESEVED_BITS 0xffffffff1ffaffc0ULL
@@ -104,55 +103,6 @@ struct segment_descriptor_64 {
 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
                           unsigned long arg);
 
-static struct inode *kvmfs_inode(struct file_operations *fops)
-{
-       int error = -ENOMEM;
-       struct inode *inode = new_inode(kvmfs_mnt->mnt_sb);
-
-       if (!inode)
-               goto eexit_1;
-
-       inode->i_fop = fops;
-
-       /*
-        * Mark the inode dirty from the very beginning,
-        * that way it will never be moved to the dirty
-        * list because mark_inode_dirty() will think
-        * that it already _is_ on the dirty list.
-        */
-       inode->i_state = I_DIRTY;
-       inode->i_mode = S_IRUSR | S_IWUSR;
-       inode->i_uid = current->fsuid;
-       inode->i_gid = current->fsgid;
-       inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
-       return inode;
-
-eexit_1:
-       return ERR_PTR(error);
-}
-
-static struct file *kvmfs_file(struct inode *inode, void *private_data)
-{
-       struct file *file = get_empty_filp();
-
-       if (!file)
-               return ERR_PTR(-ENFILE);
-
-       file->f_path.mnt = mntget(kvmfs_mnt);
-       file->f_path.dentry = d_alloc_anon(inode);
-       if (!file->f_path.dentry)
-               return ERR_PTR(-ENOMEM);
-       file->f_mapping = inode->i_mapping;
-
-       file->f_pos = 0;
-       file->f_flags = O_RDWR;
-       file->f_op = inode->i_fop;
-       file->f_mode = FMODE_READ | FMODE_WRITE;
-       file->f_version = 0;
-       file->private_data = private_data;
-       return file;
-}
-
 unsigned long segment_base(u16 selector)
 {
        struct descriptor_table gdt;
@@ -2413,34 +2363,12 @@ static int create_vcpu_fd(struct kvm_vcpu *vcpu)
        struct inode *inode;
        struct file *file;
 
+       r = anon_inode_getfd(&fd, &inode, &file,
+                            "kvm-vcpu", &kvm_vcpu_fops, vcpu);
+       if (r)
+               return r;
        atomic_inc(&vcpu->kvm->filp->f_count);
-       inode = kvmfs_inode(&kvm_vcpu_fops);
-       if (IS_ERR(inode)) {
-               r = PTR_ERR(inode);
-               goto out1;
-       }
-
-       file = kvmfs_file(inode, vcpu);
-       if (IS_ERR(file)) {
-               r = PTR_ERR(file);
-               goto out2;
-       }
-
-       r = get_unused_fd();
-       if (r < 0)
-               goto out3;
-       fd = r;
-       fd_install(fd, file);
-
        return fd;
-
-out3:
-       fput(file);
-out2:
-       iput(inode);
-out1:
-       fput(vcpu->kvm->filp);
-       return r;
 }
 
 /*
@@ -2905,41 +2833,18 @@ static int kvm_dev_ioctl_create_vm(void)
        struct file *file;
        struct kvm *kvm;
 
-       inode = kvmfs_inode(&kvm_vm_fops);
-       if (IS_ERR(inode)) {
-               r = PTR_ERR(inode);
-               goto out1;
-       }
-
        kvm = kvm_create_vm();
-       if (IS_ERR(kvm)) {
-               r = PTR_ERR(kvm);
-               goto out2;
+       if (IS_ERR(kvm))
+               return PTR_ERR(kvm);
+       r = anon_inode_getfd(&fd, &inode, &file, "kvm-vm", &kvm_vm_fops, kvm);
+       if (r) {
+               kvm_destroy_vm(kvm);
+               return r;
        }
 
-       file = kvmfs_file(inode, kvm);
-       if (IS_ERR(file)) {
-               r = PTR_ERR(file);
-               goto out3;
-       }
        kvm->filp = file;
 
-       r = get_unused_fd();
-       if (r < 0)
-               goto out4;
-       fd = r;
-       fd_install(fd, file);
-
        return fd;
-
-out4:
-       fput(file);
-out3:
-       kvm_destroy_vm(kvm);
-out2:
-       iput(inode);
-out1:
-       return r;
 }
 
 static long kvm_dev_ioctl(struct file *filp,
@@ -3211,18 +3116,6 @@ static struct sys_device kvm_sysdev = {
 
 hpa_t bad_page_address;
 
-static int kvmfs_get_sb(struct file_system_type *fs_type, int flags,
-                       const char *dev_name, void *data, struct vfsmount *mnt)
-{
-       return get_sb_pseudo(fs_type, "kvm:", NULL, KVMFS_SUPER_MAGIC, mnt);
-}
-
-static struct file_system_type kvm_fs_type = {
-       .name           = "kvmfs",
-       .get_sb         = kvmfs_get_sb,
-       .kill_sb        = kill_anon_super,
-};
-
 int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module)
 {
        int r;
@@ -3307,14 +3200,6 @@ static __init int kvm_init(void)
        if (r)
                goto out4;
 
-       r = register_filesystem(&kvm_fs_type);
-       if (r)
-               goto out3;
-
-       kvmfs_mnt = kern_mount(&kvm_fs_type);
-       r = PTR_ERR(kvmfs_mnt);
-       if (IS_ERR(kvmfs_mnt))
-               goto out2;
        kvm_init_debug();
 
        kvm_init_msr_list();
@@ -3331,10 +3216,6 @@ static __init int kvm_init(void)
 
 out:
        kvm_exit_debug();
-       mntput(kvmfs_mnt);
-out2:
-       unregister_filesystem(&kvm_fs_type);
-out3:
        kvm_mmu_module_exit();
 out4:
        return r;
@@ -3344,8 +3225,6 @@ static __exit void kvm_exit(void)
 {
        kvm_exit_debug();
        __free_page(pfn_to_page(bad_page_address >> PAGE_SHIFT));
-       mntput(kvmfs_mnt);
-       unregister_filesystem(&kvm_fs_type);
        kvm_mmu_module_exit();
 }
 

diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index 40fe3a3222e499251abda536332f52a5dea2d884..edc67486238f353ee58803cf5e829548104496f5 100644 (file)
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -139,6 +139,7 @@ err_put_filp:
        put_filp(file);
        return error;
 }
+EXPORT_SYMBOL_GPL(anon_inode_getfd);
 
 /*
  * A single inode exist for all anon_inode files. Contrary to pipes,

diff --git a/include/linux/magic.h b/include/linux/magic.h
index 9d713c03e3da681664b31fb55e0ecb82df5cc072..36cc20dfd1427398daaad3a7b2fc0faeaaa04e93 100644 (file)
--- a/include/linux/magic.h
+++ b/include/linux/magic.h
@@ -13,7 +13,6 @@
 #define HPFS_SUPER_MAGIC       0xf995e849
 #define ISOFS_SUPER_MAGIC      0x9660
 #define JFFS2_SUPER_MAGIC      0x72b6
-#define KVMFS_SUPER_MAGIC      0x19700426
 #define ANON_INODE_FS_MAGIC    0x09041934
 
 #define MINIX_SUPER_MAGIC      0x137F          /* original minix fs */