fs: replace mmap hook with .mmap_prepare for simple mappings

Since commit c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file
callback"), the f_op->mmap() hook has been deprecated in favour of
f_op->mmap_prepare().

This callback is invoked in the mmap() logic far earlier, so error handling
can be performed more safely without complicated and bug-prone state
unwinding required should an error arise.

This hook also avoids passing a pointer to a not-yet-correctly-established
VMA avoiding any issues with referencing this data structure.

It rather provides a pointer to the new struct vm_area_desc descriptor type
which contains all required state and allows easy setting of required
parameters without any consideration needing to be paid to locking or
reference counts.

Note that nested filesystems like overlayfs are compatible with an
.mmap_prepare() callback since commit bb666b7c2707 ("mm: add mmap_prepare()
compatibility layer for nested file systems").

In this patch we apply this change to file systems with relatively simple
mmap() hook logic - exfat, ceph, f2fs, bcachefs, zonefs, btrfs, ocfs2,
orangefs, nilfs2, romfs, ramfs and aio.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Link: https://lore.kernel.org/f528ac4f35b9378931bd800920fee53fc0c5c74d.1750099179.git.lorenzo.stoakes@oracle.com
Acked-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/aio.c b/fs/aio.c
index 793b7b15ec4bc23745e7ec4c74392cde8fe7fb9b..7fc7b6221312c399e9c131a0a29c9d62f9073bfe 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -392,15 +392,15 @@ static const struct vm_operations_struct aio_ring_vm_ops = {
 #endif
 };
 
-static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
+static int aio_ring_mmap_prepare(struct vm_area_desc *desc)
 {
-       vm_flags_set(vma, VM_DONTEXPAND);
-       vma->vm_ops = &aio_ring_vm_ops;
+       desc->vm_flags |= VM_DONTEXPAND;
+       desc->vm_ops = &aio_ring_vm_ops;
        return 0;
 }
 
 static const struct file_operations aio_ring_fops = {
-       .mmap = aio_ring_mmap,
+       .mmap_prepare = aio_ring_mmap_prepare,
 };
 
 #if IS_ENABLED(CONFIG_MIGRATION)

diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index 3063a8ddc2dfae1852c9bfdea999beeece1a6510..9c2238edc0e3be6edb6a17ffdd012b61714f3f73 100644 (file)
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -1553,11 +1553,11 @@ static const struct vm_operations_struct bch_vm_ops = {
        .page_mkwrite   = bch2_page_mkwrite,
 };
 
-static int bch2_mmap(struct file *file, struct vm_area_struct *vma)
+static int bch2_mmap_prepare(struct vm_area_desc *desc)
 {
-       file_accessed(file);
+       file_accessed(desc->file);
 
-       vma->vm_ops = &bch_vm_ops;
+       desc->vm_ops = &bch_vm_ops;
        return 0;
 }
 
@@ -1740,7 +1740,7 @@ static const struct file_operations bch_file_operations = {
        .llseek         = bch2_llseek,
        .read_iter      = bch2_read_iter,
        .write_iter     = bch2_write_iter,
-       .mmap           = bch2_mmap,
+       .mmap_prepare   = bch2_mmap_prepare,
        .get_unmapped_area = thp_get_unmapped_area,
        .fsync          = bch2_fsync,
        .splice_read    = filemap_splice_read,

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 8ce6f45f45e0bbfb1fb743ec90dd81e678d792d7..06bd30b35b954bc249cafdb1de81108fd9d3f5df 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1978,15 +1978,16 @@ static const struct vm_operations_struct btrfs_file_vm_ops = {
        .page_mkwrite   = btrfs_page_mkwrite,
 };
 
-static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
+static int btrfs_file_mmap_prepare(struct vm_area_desc *desc)
 {
+       struct file *filp = desc->file;
        struct address_space *mapping = filp->f_mapping;
 
        if (!mapping->a_ops->read_folio)
                return -ENOEXEC;
 
        file_accessed(filp);
-       vma->vm_ops = &btrfs_file_vm_ops;
+       desc->vm_ops = &btrfs_file_vm_ops;
 
        return 0;
 }
@@ -3765,7 +3766,7 @@ const struct file_operations btrfs_file_operations = {
        .splice_read    = filemap_splice_read,
        .write_iter     = btrfs_file_write_iter,
        .splice_write   = iter_file_splice_write,
-       .mmap           = btrfs_file_mmap,
+       .mmap_prepare   = btrfs_file_mmap_prepare,
        .open           = btrfs_file_open,
        .release        = btrfs_release_file,
        .get_unmapped_area = thp_get_unmapped_area,

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 60a621b00c656dbcc4aa637a25c87a1a94c330ab..3a6459356e705b6df378697e00fafd76e1df26eb 100644 (file)
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -2330,13 +2330,13 @@ static const struct vm_operations_struct ceph_vmops = {
        .page_mkwrite   = ceph_page_mkwrite,
 };
 
-int ceph_mmap(struct file *file, struct vm_area_struct *vma)
+int ceph_mmap_prepare(struct vm_area_desc *desc)
 {
-       struct address_space *mapping = file->f_mapping;
+       struct address_space *mapping = desc->file->f_mapping;
 
        if (!mapping->a_ops->read_folio)
                return -ENOEXEC;
-       vma->vm_ops = &ceph_vmops;
+       desc->vm_ops = &ceph_vmops;
        return 0;
 }
 

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index a7254cab44cc2e24186f5aa67169f11857e7b8de..8c06dc4655a8f53924fd5f9720ca33e6d6e9b854 100644 (file)
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -3171,7 +3171,7 @@ const struct file_operations ceph_file_fops = {
        .llseek = ceph_llseek,
        .read_iter = ceph_read_iter,
        .write_iter = ceph_write_iter,
-       .mmap = ceph_mmap,
+       .mmap_prepare = ceph_mmap_prepare,
        .fsync = ceph_fsync,
        .lock = ceph_lock,
        .setlease = simple_nosetlease,

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index bb0db0cc8003947c5ff8595a5aba3c74d8c0632d..cf176aab0f82399aa4f8ea0fd16fb61f40c73030 100644 (file)
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1286,7 +1286,7 @@ extern void __ceph_touch_fmode(struct ceph_inode_info *ci,
 /* addr.c */
 extern const struct address_space_operations ceph_aops;
 extern const struct netfs_request_ops ceph_netfs_ops;
-extern int ceph_mmap(struct file *file, struct vm_area_struct *vma);
+int ceph_mmap_prepare(struct vm_area_desc *desc);
 extern int ceph_uninline_data(struct file *file);
 extern int ceph_pool_perm_check(struct inode *inode, int need);
 extern void ceph_pool_perm_destroy(struct ceph_mds_client* mdsc);

diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 841a5b18e3dfdb3566ec28ca7096a28713b17ffa..fbd37245f8c437409ca571fccfcce5a42acea3f8 100644 (file)
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -683,13 +683,15 @@ static const struct vm_operations_struct exfat_file_vm_ops = {
        .page_mkwrite   = exfat_page_mkwrite,
 };
 
-static int exfat_file_mmap(struct file *file, struct vm_area_struct *vma)
+static int exfat_file_mmap_prepare(struct vm_area_desc *desc)
 {
-       if (unlikely(exfat_forced_shutdown(file_inode(file)->i_sb)))
+       struct file *file = desc->file;
+
+       if (unlikely(exfat_forced_shutdown(file_inode(desc->file)->i_sb)))
                return -EIO;
 
        file_accessed(file);
-       vma->vm_ops = &exfat_file_vm_ops;
+       desc->vm_ops = &exfat_file_vm_ops;
        return 0;
 }
 
@@ -710,7 +712,7 @@ const struct file_operations exfat_file_operations = {
 #ifdef CONFIG_COMPAT
        .compat_ioctl = exfat_compat_ioctl,
 #endif
-       .mmap           = exfat_file_mmap,
+       .mmap_prepare   = exfat_file_mmap_prepare,
        .fsync          = exfat_file_fsync,
        .splice_read    = exfat_splice_read,
        .splice_write   = iter_file_splice_write,

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 6bd3de64f2a83d7c1ce5c14d50a6f434ceccac72..7af2b49b7e8a3a2bff89a5e6180659555042d892 100644 (file)
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -532,8 +532,9 @@ static loff_t f2fs_llseek(struct file *file, loff_t offset, int whence)
        return -EINVAL;
 }
 
-static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma)
+static int f2fs_file_mmap_prepare(struct vm_area_desc *desc)
 {
+       struct file *file = desc->file;
        struct inode *inode = file_inode(file);
 
        if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
@@ -543,7 +544,7 @@ static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma)
                return -EOPNOTSUPP;
 
        file_accessed(file);
-       vma->vm_ops = &f2fs_file_vm_ops;
+       desc->vm_ops = &f2fs_file_vm_ops;
 
        f2fs_down_read(&F2FS_I(inode)->i_sem);
        set_inode_flag(inode, FI_MMAP_FILE);
@@ -5376,7 +5377,7 @@ const struct file_operations f2fs_file_operations = {
        .iopoll         = iocb_bio_iopoll,
        .open           = f2fs_file_open,
        .release        = f2fs_release_file,
-       .mmap           = f2fs_file_mmap,
+       .mmap_prepare   = f2fs_file_mmap_prepare,
        .flush          = f2fs_file_flush,
        .fsync          = f2fs_sync_file,
        .fallocate      = f2fs_fallocate,

diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
index 0e3fc5ba33c73d7f22deefc1cb68ee8395a1efa4..1b8d754db44d44d25dcd13f008d266ec83c74d3f 100644 (file)
--- a/fs/nilfs2/file.c
+++ b/fs/nilfs2/file.c
@@ -125,10 +125,10 @@ static const struct vm_operations_struct nilfs_file_vm_ops = {
        .page_mkwrite   = nilfs_page_mkwrite,
 };
 
-static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
+static int nilfs_file_mmap_prepare(struct vm_area_desc *desc)
 {
-       file_accessed(file);
-       vma->vm_ops = &nilfs_file_vm_ops;
+       file_accessed(desc->file);
+       desc->vm_ops = &nilfs_file_vm_ops;
        return 0;
 }
 
@@ -144,7 +144,7 @@ const struct file_operations nilfs_file_operations = {
 #ifdef CONFIG_COMPAT
        .compat_ioctl   = nilfs_compat_ioctl,
 #endif /* CONFIG_COMPAT */
-       .mmap           = nilfs_file_mmap,
+       .mmap_prepare   = nilfs_file_mmap_prepare,
        .open           = generic_file_open,
        /* .release     = nilfs_release_file, */
        .fsync          = nilfs_sync_file,

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 2056cf08ac1e896c5d8b3e4285dd6b6fa6793ffe..21d797ccccd068c46a923f2ec255d470fc8cad3f 100644 (file)
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2800,7 +2800,7 @@ const struct inode_operations ocfs2_special_file_iops = {
  */
 const struct file_operations ocfs2_fops = {
        .llseek         = ocfs2_file_llseek,
-       .mmap           = ocfs2_mmap,
+       .mmap_prepare   = ocfs2_mmap_prepare,
        .fsync          = ocfs2_sync_file,
        .release        = ocfs2_file_release,
        .open           = ocfs2_file_open,
@@ -2850,7 +2850,7 @@ const struct file_operations ocfs2_dops = {
  */
 const struct file_operations ocfs2_fops_no_plocks = {
        .llseek         = ocfs2_file_llseek,
-       .mmap           = ocfs2_mmap,
+       .mmap_prepare   = ocfs2_mmap_prepare,
        .fsync          = ocfs2_sync_file,
        .release        = ocfs2_file_release,
        .open           = ocfs2_file_open,

diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
index 6a314e9f2b4931ca3e1fb3e250019731b7d8f643..50e2faf64c1976f073290b128a14e48fbb0a334e 100644 (file)
--- a/fs/ocfs2/mmap.c
+++ b/fs/ocfs2/mmap.c
@@ -159,8 +159,9 @@ static const struct vm_operations_struct ocfs2_file_vm_ops = {
        .page_mkwrite   = ocfs2_page_mkwrite,
 };
 
-int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
+int ocfs2_mmap_prepare(struct vm_area_desc *desc)
 {
+       struct file *file = desc->file;
        int ret = 0, lock_level = 0;
 
        ret = ocfs2_inode_lock_atime(file_inode(file),
@@ -171,7 +172,7 @@ int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
        }
        ocfs2_inode_unlock(file_inode(file), lock_level);
 out:
-       vma->vm_ops = &ocfs2_file_vm_ops;
+       desc->vm_ops = &ocfs2_file_vm_ops;
        return 0;
 }
 

diff --git a/fs/ocfs2/mmap.h b/fs/ocfs2/mmap.h
index 1051507cc6841156d631879f759e0c57bfcb7cee..d21c30de6b8c27fb0f258bd54a8240c7565199bd 100644 (file)
--- a/fs/ocfs2/mmap.h
+++ b/fs/ocfs2/mmap.h
@@ -2,6 +2,6 @@
 #ifndef OCFS2_MMAP_H
 #define OCFS2_MMAP_H
 
-int ocfs2_mmap(struct file *file, struct vm_area_struct *vma);
+int ocfs2_mmap_prepare(struct vm_area_desc *desc);
 
 #endif  /* OCFS2_MMAP_H */

diff --git a/fs/orangefs/file.c b/fs/orangefs/file.c
index 90c49c0de243f3fbcc1f76792aea669e24639a31..919f99b16834160dd8cc87faf9b8802aa02796cf 100644 (file)
--- a/fs/orangefs/file.c
+++ b/fs/orangefs/file.c
@@ -398,8 +398,9 @@ static const struct vm_operations_struct orangefs_file_vm_ops = {
 /*
  * Memory map a region of a file.
  */
-static int orangefs_file_mmap(struct file *file, struct vm_area_struct *vma)
+static int orangefs_file_mmap_prepare(struct vm_area_desc *desc)
 {
+       struct file *file = desc->file;
        int ret;
 
        ret = orangefs_revalidate_mapping(file_inode(file));
@@ -410,10 +411,11 @@ static int orangefs_file_mmap(struct file *file, struct vm_area_struct *vma)
                     "orangefs_file_mmap: called on %pD\n", file);
 
        /* set the sequential readahead hint */
-       vm_flags_mod(vma, VM_SEQ_READ, VM_RAND_READ);
+       desc->vm_flags |= VM_SEQ_READ;
+       desc->vm_flags &= ~VM_RAND_READ;
 
        file_accessed(file);
-       vma->vm_ops = &orangefs_file_vm_ops;
+       desc->vm_ops = &orangefs_file_vm_ops;
        return 0;
 }
 
@@ -574,7 +576,7 @@ const struct file_operations orangefs_file_operations = {
        .read_iter      = orangefs_file_read_iter,
        .write_iter     = orangefs_file_write_iter,
        .lock           = orangefs_lock,
-       .mmap           = orangefs_file_mmap,
+       .mmap_prepare   = orangefs_file_mmap_prepare,
        .open           = generic_file_open,
        .splice_read    = orangefs_file_splice_read,
        .splice_write   = iter_file_splice_write,

diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
index 7a6d980e614dbe3a1de7d9018e6e004fae1fd311..77b8ca2757e0d698a9281b48637ade61dd2fdfff 100644 (file)
--- a/fs/ramfs/file-nommu.c
+++ b/fs/ramfs/file-nommu.c
@@ -28,7 +28,7 @@ static unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
                                                   unsigned long len,
                                                   unsigned long pgoff,
                                                   unsigned long flags);
-static int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma);
+static int ramfs_nommu_mmap_prepare(struct vm_area_desc *desc);
 
 static unsigned ramfs_mmap_capabilities(struct file *file)
 {
@@ -38,7 +38,7 @@ static unsigned ramfs_mmap_capabilities(struct file *file)
 
 const struct file_operations ramfs_file_operations = {
        .mmap_capabilities      = ramfs_mmap_capabilities,
-       .mmap                   = ramfs_nommu_mmap,
+       .mmap_prepare           = ramfs_nommu_mmap_prepare,
        .get_unmapped_area      = ramfs_nommu_get_unmapped_area,
        .read_iter              = generic_file_read_iter,
        .write_iter             = generic_file_write_iter,
@@ -262,12 +262,12 @@ out:
 /*
  * set up a mapping for shared memory segments
  */
-static int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma)
+static int ramfs_nommu_mmap_prepare(struct vm_area_desc *desc)
 {
-       if (!is_nommu_shared_mapping(vma->vm_flags))
+       if (!is_nommu_shared_mapping(desc->vm_flags))
                return -ENOSYS;
 
-       file_accessed(file);
-       vma->vm_ops = &generic_file_vm_ops;
+       file_accessed(desc->file);
+       desc->vm_ops = &generic_file_vm_ops;
        return 0;
 }

diff --git a/fs/romfs/mmap-nommu.c b/fs/romfs/mmap-nommu.c
index 4520ca41386768df7a3f3c1ec56ba8e4d6b68d9b..4b77c6dc4418141057718ea208839e35e22eb771 100644 (file)
--- a/fs/romfs/mmap-nommu.c
+++ b/fs/romfs/mmap-nommu.c
@@ -61,9 +61,9 @@ static unsigned long romfs_get_unmapped_area(struct file *file,
  * permit a R/O mapping to be made directly through onto an MTD device if
  * possible
  */
-static int romfs_mmap(struct file *file, struct vm_area_struct *vma)
+static int romfs_mmap_prepare(struct vm_area_desc *desc)
 {
-       return is_nommu_shared_mapping(vma->vm_flags) ? 0 : -ENOSYS;
+       return is_nommu_shared_mapping(desc->vm_flags) ? 0 : -ENOSYS;
 }
 
 static unsigned romfs_mmap_capabilities(struct file *file)
@@ -79,7 +79,7 @@ const struct file_operations romfs_ro_fops = {
        .llseek                 = generic_file_llseek,
        .read_iter              = generic_file_read_iter,
        .splice_read            = filemap_splice_read,
-       .mmap                   = romfs_mmap,
+       .mmap_prepare           = romfs_mmap_prepare,
        .get_unmapped_area      = romfs_get_unmapped_area,
        .mmap_capabilities      = romfs_mmap_capabilities,
 };

diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c
index 42e2c0065bb30dd326cd57856ee7cdb987fddebc..c1848163b378473a5522d9b8d08a39545de583c8 100644 (file)
--- a/fs/zonefs/file.c
+++ b/fs/zonefs/file.c
@@ -312,8 +312,10 @@ static const struct vm_operations_struct zonefs_file_vm_ops = {
        .page_mkwrite   = zonefs_filemap_page_mkwrite,
 };
 
-static int zonefs_file_mmap(struct file *file, struct vm_area_struct *vma)
+static int zonefs_file_mmap_prepare(struct vm_area_desc *desc)
 {
+       struct file *file = desc->file;
+
        /*
         * Conventional zones accept random writes, so their files can support
         * shared writable mappings. For sequential zone files, only read
@@ -321,11 +323,11 @@ static int zonefs_file_mmap(struct file *file, struct vm_area_struct *vma)
         * ordering between msync() and page cache writeback.
         */
        if (zonefs_inode_is_seq(file_inode(file)) &&
-           (vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
+           (desc->vm_flags & VM_SHARED) && (desc->vm_flags & VM_MAYWRITE))
                return -EINVAL;
 
        file_accessed(file);
-       vma->vm_ops = &zonefs_file_vm_ops;
+       desc->vm_ops = &zonefs_file_vm_ops;
 
        return 0;
 }
@@ -850,7 +852,7 @@ const struct file_operations zonefs_file_operations = {
        .open           = zonefs_file_open,
        .release        = zonefs_file_release,
        .fsync          = zonefs_file_fsync,
-       .mmap           = zonefs_file_mmap,
+       .mmap_prepare   = zonefs_file_mmap_prepare,
        .llseek         = zonefs_file_llseek,
        .read_iter      = zonefs_file_read_iter,
        .write_iter     = zonefs_file_write_iter,