From ea8157ab2ae5e914dd427e5cfab533b6da3819cd Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 21 May 2019 07:55:45 +0100 Subject: zsfold: Convert zsfold to use the new mount API Convert the zsfold filesystem to the new internal mount API as the old one will be obsoleted and removed. This allows greater flexibility in communication of mount parameters between userspace, the VFS and the filesystem. See Documentation/filesystems/mount_api.txt for more information. Signed-off-by: David Howells --- include/uapi/linux/magic.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi/linux/magic.h') diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h index f8c00045d537..85c1119d0b0b 100644 --- a/include/uapi/linux/magic.h +++ b/include/uapi/linux/magic.h @@ -91,5 +91,6 @@ #define UDF_SUPER_MAGIC 0x15013346 #define BALLOON_KVM_MAGIC 0x13661366 #define ZSMALLOC_MAGIC 0x58295829 +#define Z3FOLD_MAGIC 0x33 #endif /* __LINUX_MAGIC_H__ */ -- cgit v1.2.3 From ed63bb1d1f8469586006a9ca63c42344401aa2ab Mon Sep 17 00:00:00 2001 From: Greg Hackmann Date: Thu, 13 Jun 2019 15:34:06 -0700 Subject: dma-buf: give each buffer a full-fledged inode By traversing /proc/*/fd and /proc/*/map_files, processes with CAP_ADMIN can get a lot of fine-grained data about how shmem buffers are shared among processes. stat(2) on each entry gives the caller a unique ID (st_ino), the buffer's size (st_size), and even the number of pages currently charged to the buffer (st_blocks / 512). In contrast, all dma-bufs share the same anonymous inode. So while we can count how many dma-buf fds or mappings a process has, we can't get the size of the backing buffers or tell if two entries point to the same dma-buf. On systems with debugfs, we can get a per-buffer breakdown of size and reference count, but can't tell which processes are actually holding the references to each buffer. Replace the singleton inode with full-fledged inodes allocated by alloc_anon_inode(). This involves creating and mounting a mini-pseudo-filesystem for dma-buf, following the example in fs/aio.c. Signed-off-by: Greg Hackmann Signed-off-by: Chenbo Feng Signed-off-by: Sumit Semwal Link: https://patchwork.freedesktop.org/patch/msgid/20190613223408.139221-2-fengc@google.com --- drivers/dma-buf/dma-buf.c | 63 +++++++++++++++++++++++++++++++++++++++++----- include/uapi/linux/magic.h | 1 + 2 files changed, 58 insertions(+), 6 deletions(-) (limited to 'include/uapi/linux/magic.h') diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index f4104a21b069..3612ccededd6 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -34,8 +34,10 @@ #include #include #include +#include #include +#include static inline int is_dma_buf_file(struct file *); @@ -46,6 +48,25 @@ struct dma_buf_list { static struct dma_buf_list db_list; +static const struct dentry_operations dma_buf_dentry_ops = { + .d_dname = simple_dname, +}; + +static struct vfsmount *dma_buf_mnt; + +static struct dentry *dma_buf_fs_mount(struct file_system_type *fs_type, + int flags, const char *name, void *data) +{ + return mount_pseudo(fs_type, "dmabuf:", NULL, &dma_buf_dentry_ops, + DMA_BUF_MAGIC); +} + +static struct file_system_type dma_buf_fs_type = { + .name = "dmabuf", + .mount = dma_buf_fs_mount, + .kill_sb = kill_anon_super, +}; + static int dma_buf_release(struct inode *inode, struct file *file) { struct dma_buf *dmabuf; @@ -342,6 +363,31 @@ static inline int is_dma_buf_file(struct file *file) return file->f_op == &dma_buf_fops; } +static struct file *dma_buf_getfile(struct dma_buf *dmabuf, int flags) +{ + struct file *file; + struct inode *inode = alloc_anon_inode(dma_buf_mnt->mnt_sb); + + if (IS_ERR(inode)) + return ERR_CAST(inode); + + inode->i_size = dmabuf->size; + inode_set_bytes(inode, dmabuf->size); + + file = alloc_file_pseudo(inode, dma_buf_mnt, "dmabuf", + flags, &dma_buf_fops); + if (IS_ERR(file)) + goto err_alloc_file; + file->f_flags = flags & (O_ACCMODE | O_NONBLOCK); + file->private_data = dmabuf; + + return file; + +err_alloc_file: + iput(inode); + return file; +} + /** * DOC: dma buf device access * @@ -436,8 +482,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) } dmabuf->resv = resv; - file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, - exp_info->flags); + file = dma_buf_getfile(dmabuf, exp_info->flags); if (IS_ERR(file)) { ret = PTR_ERR(file); goto err_dmabuf; @@ -1055,8 +1100,8 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) return ret; seq_puts(s, "\nDma-buf Objects:\n"); - seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\n", - "size", "flags", "mode", "count"); + seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\n", + "size", "flags", "mode", "count", "ino"); list_for_each_entry(buf_obj, &db_list.head, list_node) { ret = mutex_lock_interruptible(&buf_obj->lock); @@ -1067,11 +1112,12 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) continue; } - seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n", + seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\n", buf_obj->size, buf_obj->file->f_flags, buf_obj->file->f_mode, file_count(buf_obj->file), - buf_obj->exp_name); + buf_obj->exp_name, + file_inode(buf_obj->file)->i_ino); robj = buf_obj->resv; while (true) { @@ -1167,6 +1213,10 @@ static inline void dma_buf_uninit_debugfs(void) static int __init dma_buf_init(void) { + dma_buf_mnt = kern_mount(&dma_buf_fs_type); + if (IS_ERR(dma_buf_mnt)) + return PTR_ERR(dma_buf_mnt); + mutex_init(&db_list.lock); INIT_LIST_HEAD(&db_list.head); dma_buf_init_debugfs(); @@ -1177,5 +1227,6 @@ subsys_initcall(dma_buf_init); static void __exit dma_buf_deinit(void) { dma_buf_uninit_debugfs(); + kern_unmount(dma_buf_mnt); } __exitcall(dma_buf_deinit); diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h index f8c00045d537..665e18627f78 100644 --- a/include/uapi/linux/magic.h +++ b/include/uapi/linux/magic.h @@ -91,5 +91,6 @@ #define UDF_SUPER_MAGIC 0x15013346 #define BALLOON_KVM_MAGIC 0x13661366 #define ZSMALLOC_MAGIC 0x58295829 +#define DMA_BUF_MAGIC 0x444d4142 /* "DMAB" */ #endif /* __LINUX_MAGIC_H__ */ -- cgit v1.2.3