[PATCH] hostfs: convert hostfs to use the new mount api

[PATCH] hostfs: convert hostfs to use the new mount api

[Hongbo Li]

Convert the hostfs filesystem to use the new mount API.

Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
 fs/hostfs/hostfs_kern.c | 83 ++++++++++++++++++++++++++++++-----------
 1 file changed, 62 insertions(+), 21 deletions(-)

diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index a73d27c4dd58..24e64dda65df 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -16,11 +16,16 @@
 #include <linux/seq_file.h>
 #include <linux/writeback.h>
 #include <linux/mount.h>
+#include <linux/fs_context.h>
 #include <linux/namei.h>
 #include "hostfs.h"
 #include <init.h>
 #include <kern.h>
 
+struct hostfs_fs_info {
+	char *host_root_path;
+};
+
 struct hostfs_inode_info {
 	int fd;
 	fmode_t mode;
@@ -90,8 +95,10 @@ static char *__dentry_name(struct dentry *dentry, char *name)
 	char *p = dentry_path_raw(dentry, name, PATH_MAX);
 	char *root;
 	size_t len;
+	struct hostfs_fs_info *fsi;
 
-	root = dentry->d_sb->s_fs_info;
+	fsi = dentry->d_sb->s_fs_info;
+	root = fsi->host_root_path;
 	len = strlen(root);
 	if (IS_ERR(p)) {
 		__putname(name);
@@ -196,8 +203,10 @@ static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf)
 	long long f_bavail;
 	long long f_files;
 	long long f_ffree;
+	struct hostfs_fs_info *fsi;
 
-	err = do_statfs(dentry->d_sb->s_fs_info,
+	fsi = dentry->d_sb->s_fs_info;
+	err = do_statfs(fsi->host_root_path,
 			&sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
 			&f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
 			&sf->f_namelen);
@@ -245,7 +254,11 @@ static void hostfs_free_inode(struct inode *inode)
 
 static int hostfs_show_options(struct seq_file *seq, struct dentry *root)
 {
-	const char *root_path = root->d_sb->s_fs_info;
+	struct hostfs_fs_info *fsi;
+	const char *root_path;
+
+	fsi = root->d_sb->s_fs_info;
+	root_path = fsi->host_root_path;
 	size_t offset = strlen(root_ino) + 1;
 
 	if (strlen(root_path) > offset)
@@ -922,10 +935,11 @@ static const struct inode_operations hostfs_link_iops = {
 	.get_link	= hostfs_get_link,
 };
 
-static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
+static int hostfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
+	struct hostfs_fs_info *fsi = sb->s_fs_info;
 	struct inode *root_inode;
-	char *host_root_path, *req_root = d;
+	char *host_root;
 	int err;
 
 	sb->s_blocksize = 1024;
@@ -939,15 +953,15 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 		return err;
 
 	/* NULL is printed as '(null)' by printf(): avoid that. */
-	if (req_root == NULL)
-		req_root = "";
+	if (fc->source == NULL)
+		host_root = "";
 
-	sb->s_fs_info = host_root_path =
-		kasprintf(GFP_KERNEL, "%s/%s", root_ino, req_root);
-	if (host_root_path == NULL)
+	fsi->host_root_path =
+		kasprintf(GFP_KERNEL, "%s/%s", root_ino, host_root);
+	if (fsi->host_root_path == NULL)
 		return -ENOMEM;
 
-	root_inode = hostfs_iget(sb, host_root_path);
+	root_inode = hostfs_iget(sb, fsi->host_root_path);
 	if (IS_ERR(root_inode))
 		return PTR_ERR(root_inode);
 
@@ -955,7 +969,7 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 		char *name;
 
 		iput(root_inode);
-		name = follow_link(host_root_path);
+		name = follow_link(fsi->host_root_path);
 		if (IS_ERR(name))
 			return PTR_ERR(name);
 
@@ -972,11 +986,38 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 	return 0;
 }
 
-static struct dentry *hostfs_read_sb(struct file_system_type *type,
-			  int flags, const char *dev_name,
-			  void *data)
+static int hostfs_fc_get_tree(struct fs_context *fc)
 {
-	return mount_nodev(type, flags, data, hostfs_fill_sb_common);
+	return get_tree_nodev(fc, hostfs_fill_super);
+}
+
+static void hostfs_fc_free(struct fs_context *fc)
+{
+	struct hostfs_fs_info *fsi = fc->s_fs_info;
+
+	if (!fsi)
+		return;
+
+	kfree(fsi->host_root_path);
+	kfree(fsi);
+}
+
+static const struct fs_context_operations hostfs_context_ops = {
+	.get_tree	= hostfs_fc_get_tree,
+	.free		= hostfs_fc_free,
+};
+
+static int hostfs_init_fs_context(struct fs_context *fc)
+{
+	struct hostfs_fs_info *fsi;
+
+	fsi = kzalloc(sizeof(*fsi), GFP_KERNEL);
+	if (!fsi)
+		return -ENOMEM;
+
+	fc->s_fs_info = fsi;
+	fc->ops = &hostfs_context_ops;
+	return 0;
 }
 
 static void hostfs_kill_sb(struct super_block *s)
@@ -986,11 +1027,11 @@ static void hostfs_kill_sb(struct super_block *s)
 }
 
 static struct file_system_type hostfs_type = {
-	.owner 		= THIS_MODULE,
-	.name 		= "hostfs",
-	.mount	 	= hostfs_read_sb,
-	.kill_sb	= hostfs_kill_sb,
-	.fs_flags 	= 0,
+	.owner			= THIS_MODULE,
+	.name			= "hostfs",
+	.init_fs_context	= hostfs_init_fs_context,
+	.kill_sb		= hostfs_kill_sb,
+	.fs_flags		= 0,
 };
 MODULE_ALIAS_FS("hostfs");
 
-- 
2.34.1

Re: [PATCH] hostfs: convert hostfs to use the new mount api

[kernel test robot]

Hi Hongbo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on uml/next]
[also build test WARNING on wireless-next/main wireless/main linus/master v6.9 next-20240513]
[cannot apply to uml/fixes]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Hongbo-Li/hostfs-convert-hostfs-to-use-the-new-mount-api/20240513-204233
base:   git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux next
patch link:    https://lore.kernel.org/r/20240513124141.3788846-1-lihongbo22%40huawei.com
patch subject: [PATCH] hostfs: convert hostfs to use the new mount api
config: um-allnoconfig (https://download.01.org/0day-ci/archive/20240513/202405132349.LJ3Qx7on-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240513/202405132349.LJ3Qx7on-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405132349.LJ3Qx7on-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from fs/hostfs/hostfs_kern.c:13:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from fs/hostfs/hostfs_kern.c:13:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from fs/hostfs/hostfs_kern.c:13:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     692 |         readsb(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     700 |         readsw(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     708 |         readsl(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     717 |         writesb(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     726 |         writesw(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     735 |         writesl(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
>> fs/hostfs/hostfs_kern.c:956:6: warning: variable 'host_root' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
     956 |         if (fc->source == NULL)
         |             ^~~~~~~~~~~~~~~~~~
   fs/hostfs/hostfs_kern.c:960:44: note: uninitialized use occurs here
     960 |                 kasprintf(GFP_KERNEL, "%s/%s", root_ino, host_root);
         |                                                          ^~~~~~~~~
   fs/hostfs/hostfs_kern.c:956:2: note: remove the 'if' if its condition is always true
     956 |         if (fc->source == NULL)
         |         ^~~~~~~~~~~~~~~~~~~~~~~
     957 |                 host_root = "";
   fs/hostfs/hostfs_kern.c:942:17: note: initialize the variable 'host_root' to silence this warning
     942 |         char *host_root;
         |                        ^
         |                         = NULL
   13 warnings generated.


vim +956 fs/hostfs/hostfs_kern.c

   937	
   938	static int hostfs_fill_super(struct super_block *sb, struct fs_context *fc)
   939	{
   940		struct hostfs_fs_info *fsi = sb->s_fs_info;
   941		struct inode *root_inode;
   942		char *host_root;
   943		int err;
   944	
   945		sb->s_blocksize = 1024;
   946		sb->s_blocksize_bits = 10;
   947		sb->s_magic = HOSTFS_SUPER_MAGIC;
   948		sb->s_op = &hostfs_sbops;
   949		sb->s_d_op = &simple_dentry_operations;
   950		sb->s_maxbytes = MAX_LFS_FILESIZE;
   951		err = super_setup_bdi(sb);
   952		if (err)
   953			return err;
   954	
   955		/* NULL is printed as '(null)' by printf(): avoid that. */
 > 956		if (fc->source == NULL)
   957			host_root = "";
   958	
   959		fsi->host_root_path =
   960			kasprintf(GFP_KERNEL, "%s/%s", root_ino, host_root);
   961		if (fsi->host_root_path == NULL)
   962			return -ENOMEM;
   963	
   964		root_inode = hostfs_iget(sb, fsi->host_root_path);
   965		if (IS_ERR(root_inode))
   966			return PTR_ERR(root_inode);
   967	
   968		if (S_ISLNK(root_inode->i_mode)) {
   969			char *name;
   970	
   971			iput(root_inode);
   972			name = follow_link(fsi->host_root_path);
   973			if (IS_ERR(name))
   974				return PTR_ERR(name);
   975	
   976			root_inode = hostfs_iget(sb, name);
   977			kfree(name);
   978			if (IS_ERR(root_inode))
   979				return PTR_ERR(root_inode);
   980		}
   981	
   982		sb->s_root = d_make_root(root_inode);
   983		if (sb->s_root == NULL)
   984			return -ENOMEM;
   985	
   986		return 0;
   987	}
   988	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH] hostfs: convert hostfs to use the new mount API

[Hongbo Li]

Convert the hostfs 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: Hongbo Li <lihongbo22@huawei.com>
---
 fs/hostfs/hostfs_kern.c | 83 ++++++++++++++++++++++++++++++-----------
 1 file changed, 62 insertions(+), 21 deletions(-)

diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index a73d27c4dd58..6ec3c368d7bf 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -16,11 +16,16 @@
 #include <linux/seq_file.h>
 #include <linux/writeback.h>
 #include <linux/mount.h>
+#include <linux/fs_context.h>
 #include <linux/namei.h>
 #include "hostfs.h"
 #include <init.h>
 #include <kern.h>
 
+struct hostfs_fs_info {
+	char *host_root_path;
+};
+
 struct hostfs_inode_info {
 	int fd;
 	fmode_t mode;
@@ -90,8 +95,10 @@ static char *__dentry_name(struct dentry *dentry, char *name)
 	char *p = dentry_path_raw(dentry, name, PATH_MAX);
 	char *root;
 	size_t len;
+	struct hostfs_fs_info *fsi;
 
-	root = dentry->d_sb->s_fs_info;
+	fsi = dentry->d_sb->s_fs_info;
+	root = fsi->host_root_path;
 	len = strlen(root);
 	if (IS_ERR(p)) {
 		__putname(name);
@@ -196,8 +203,10 @@ static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf)
 	long long f_bavail;
 	long long f_files;
 	long long f_ffree;
+	struct hostfs_fs_info *fsi;
 
-	err = do_statfs(dentry->d_sb->s_fs_info,
+	fsi = dentry->d_sb->s_fs_info;
+	err = do_statfs(fsi->host_root_path,
 			&sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
 			&f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
 			&sf->f_namelen);
@@ -245,7 +254,11 @@ static void hostfs_free_inode(struct inode *inode)
 
 static int hostfs_show_options(struct seq_file *seq, struct dentry *root)
 {
-	const char *root_path = root->d_sb->s_fs_info;
+	struct hostfs_fs_info *fsi;
+	const char *root_path;
+
+	fsi = root->d_sb->s_fs_info;
+	root_path = fsi->host_root_path;
 	size_t offset = strlen(root_ino) + 1;
 
 	if (strlen(root_path) > offset)
@@ -922,10 +935,11 @@ static const struct inode_operations hostfs_link_iops = {
 	.get_link	= hostfs_get_link,
 };
 
-static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
+static int hostfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
+	struct hostfs_fs_info *fsi = sb->s_fs_info;
 	struct inode *root_inode;
-	char *host_root_path, *req_root = d;
+	char *host_root = fc->source;
 	int err;
 
 	sb->s_blocksize = 1024;
@@ -939,15 +953,15 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 		return err;
 
 	/* NULL is printed as '(null)' by printf(): avoid that. */
-	if (req_root == NULL)
-		req_root = "";
+	if (fc->source == NULL)
+		host_root = "";
 
-	sb->s_fs_info = host_root_path =
-		kasprintf(GFP_KERNEL, "%s/%s", root_ino, req_root);
-	if (host_root_path == NULL)
+	fsi->host_root_path =
+		kasprintf(GFP_KERNEL, "%s/%s", root_ino, host_root);
+	if (fsi->host_root_path == NULL)
 		return -ENOMEM;
 
-	root_inode = hostfs_iget(sb, host_root_path);
+	root_inode = hostfs_iget(sb, fsi->host_root_path);
 	if (IS_ERR(root_inode))
 		return PTR_ERR(root_inode);
 
@@ -955,7 +969,7 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 		char *name;
 
 		iput(root_inode);
-		name = follow_link(host_root_path);
+		name = follow_link(fsi->host_root_path);
 		if (IS_ERR(name))
 			return PTR_ERR(name);
 
@@ -972,11 +986,38 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 	return 0;
 }
 
-static struct dentry *hostfs_read_sb(struct file_system_type *type,
-			  int flags, const char *dev_name,
-			  void *data)
+static int hostfs_fc_get_tree(struct fs_context *fc)
 {
-	return mount_nodev(type, flags, data, hostfs_fill_sb_common);
+	return get_tree_nodev(fc, hostfs_fill_super);
+}
+
+static void hostfs_fc_free(struct fs_context *fc)
+{
+	struct hostfs_fs_info *fsi = fc->s_fs_info;
+
+	if (!fsi)
+		return;
+
+	kfree(fsi->host_root_path);
+	kfree(fsi);
+}
+
+static const struct fs_context_operations hostfs_context_ops = {
+	.get_tree	= hostfs_fc_get_tree,
+	.free		= hostfs_fc_free,
+};
+
+static int hostfs_init_fs_context(struct fs_context *fc)
+{
+	struct hostfs_fs_info *fsi;
+
+	fsi = kzalloc(sizeof(*fsi), GFP_KERNEL);
+	if (!fsi)
+		return -ENOMEM;
+
+	fc->s_fs_info = fsi;
+	fc->ops = &hostfs_context_ops;
+	return 0;
 }
 
 static void hostfs_kill_sb(struct super_block *s)
@@ -986,11 +1027,11 @@ static void hostfs_kill_sb(struct super_block *s)
 }
 
 static struct file_system_type hostfs_type = {
-	.owner 		= THIS_MODULE,
-	.name 		= "hostfs",
-	.mount	 	= hostfs_read_sb,
-	.kill_sb	= hostfs_kill_sb,
-	.fs_flags 	= 0,
+	.owner			= THIS_MODULE,
+	.name			= "hostfs",
+	.init_fs_context	= hostfs_init_fs_context,
+	.kill_sb		= hostfs_kill_sb,
+	.fs_flags		= 0,
 };
 MODULE_ALIAS_FS("hostfs");
 
-- 
2.34.1

Re: [PATCH] hostfs: convert hostfs to use the new mount api

[Dan Carpenter]

Hi Hongbo,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Hongbo-Li/hostfs-convert-hostfs-to-use-the-new-mount-api/20240513-204233
base:   git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux next
patch link:    https://lore.kernel.org/r/20240513124141.3788846-1-lihongbo22%40huawei.com
patch subject: [PATCH] hostfs: convert hostfs to use the new mount api
config: um-randconfig-r081-20240517 (https://download.01.org/0day-ci/archive/20240517/202405171154.21q42SWy-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project d3455f4ddd16811401fa153298fadd2f59f6914e)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202405171154.21q42SWy-lkp@intel.com/

smatch warnings:
fs/hostfs/hostfs_kern.c:960 hostfs_fill_super() error: uninitialized symbol 'host_root'.

vim +/host_root +960 fs/hostfs/hostfs_kern.c

2c2593890079e8 Hongbo Li         2024-05-13  938  static int hostfs_fill_super(struct super_block *sb, struct fs_context *fc)
^1da177e4c3f41 Linus Torvalds    2005-04-16  939  {
2c2593890079e8 Hongbo Li         2024-05-13  940  	struct hostfs_fs_info *fsi = sb->s_fs_info;
^1da177e4c3f41 Linus Torvalds    2005-04-16  941  	struct inode *root_inode;
2c2593890079e8 Hongbo Li         2024-05-13  942  	char *host_root;
^1da177e4c3f41 Linus Torvalds    2005-04-16  943  	int err;
^1da177e4c3f41 Linus Torvalds    2005-04-16  944  
^1da177e4c3f41 Linus Torvalds    2005-04-16  945  	sb->s_blocksize = 1024;
^1da177e4c3f41 Linus Torvalds    2005-04-16  946  	sb->s_blocksize_bits = 10;
^1da177e4c3f41 Linus Torvalds    2005-04-16  947  	sb->s_magic = HOSTFS_SUPER_MAGIC;
^1da177e4c3f41 Linus Torvalds    2005-04-16  948  	sb->s_op = &hostfs_sbops;
b26d4cd385fc51 Al Viro           2013-10-25  949  	sb->s_d_op = &simple_dentry_operations;
752fa51e4c5182 Wolfgang Illmeyer 2009-06-30  950  	sb->s_maxbytes = MAX_LFS_FILESIZE;
ce72750f04d68a Sjoerd Simons     2021-11-05  951  	err = super_setup_bdi(sb);
ce72750f04d68a Sjoerd Simons     2021-11-05  952  	if (err)
74ce793bcbde5c Mickaël Salaün    2023-06-12  953  		return err;
^1da177e4c3f41 Linus Torvalds    2005-04-16  954  
b58c4e96192ee7 Andy Shevchenko   2020-03-20  955  	/* NULL is printed as '(null)' by printf(): avoid that. */
2c2593890079e8 Hongbo Li         2024-05-13  956  	if (fc->source == NULL)
2c2593890079e8 Hongbo Li         2024-05-13  957  		host_root = "";

Uninitialized on else path

^1da177e4c3f41 Linus Torvalds    2005-04-16  958  
2c2593890079e8 Hongbo Li         2024-05-13  959  	fsi->host_root_path =
2c2593890079e8 Hongbo Li         2024-05-13 @960  		kasprintf(GFP_KERNEL, "%s/%s", root_ino, host_root);
                                                                                                         ^^^^^^^^^


2c2593890079e8 Hongbo Li         2024-05-13  961  	if (fsi->host_root_path == NULL)
74ce793bcbde5c Mickaël Salaün    2023-06-12  962  		return -ENOMEM;

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH] hostfs: convert hostfs to use the new mount api

[Hongbo Li]

Thanks for your attention, I have solved the warnings in the following 
patch (the similar title: hostfs: convert hostfs to use the new mount API):

https://lore.kernel.org/all/20240515025536.3667017-1-lihongbo22@huawei.com/

or

https://patchwork.ozlabs.org/project/linux-um/patch/20240515025536.3667017-1-lihongbo22@huawei.com/

It was strange that the kernel test robot did not send the results on 
the new patch.

Thanks,
Hongbo

On 2024/5/17 19:01, Dan Carpenter wrote:
> Hi Hongbo,
> 
> kernel test robot noticed the following build warnings:
> 
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Hongbo-Li/hostfs-convert-hostfs-to-use-the-new-mount-api/20240513-204233
> base:   git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux next
> patch link:    https://lore.kernel.org/r/20240513124141.3788846-1-lihongbo22%40huawei.com
> patch subject: [PATCH] hostfs: convert hostfs to use the new mount api
> config: um-randconfig-r081-20240517 (https://download.01.org/0day-ci/archive/20240517/202405171154.21q42SWy-lkp@intel.com/config)
> compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project d3455f4ddd16811401fa153298fadd2f59f6914e)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> | Closes: https://lore.kernel.org/r/202405171154.21q42SWy-lkp@intel.com/
> 
> smatch warnings:
> fs/hostfs/hostfs_kern.c:960 hostfs_fill_super() error: uninitialized symbol 'host_root'.
> 
> vim +/host_root +960 fs/hostfs/hostfs_kern.c
> 
> 2c2593890079e8 Hongbo Li         2024-05-13  938  static int hostfs_fill_super(struct super_block *sb, struct fs_context *fc)
> ^1da177e4c3f41 Linus Torvalds    2005-04-16  939  {
> 2c2593890079e8 Hongbo Li         2024-05-13  940  	struct hostfs_fs_info *fsi = sb->s_fs_info;
> ^1da177e4c3f41 Linus Torvalds    2005-04-16  941  	struct inode *root_inode;
> 2c2593890079e8 Hongbo Li         2024-05-13  942  	char *host_root;
> ^1da177e4c3f41 Linus Torvalds    2005-04-16  943  	int err;
> ^1da177e4c3f41 Linus Torvalds    2005-04-16  944
> ^1da177e4c3f41 Linus Torvalds    2005-04-16  945  	sb->s_blocksize = 1024;
> ^1da177e4c3f41 Linus Torvalds    2005-04-16  946  	sb->s_blocksize_bits = 10;
> ^1da177e4c3f41 Linus Torvalds    2005-04-16  947  	sb->s_magic = HOSTFS_SUPER_MAGIC;
> ^1da177e4c3f41 Linus Torvalds    2005-04-16  948  	sb->s_op = &hostfs_sbops;
> b26d4cd385fc51 Al Viro           2013-10-25  949  	sb->s_d_op = &simple_dentry_operations;
> 752fa51e4c5182 Wolfgang Illmeyer 2009-06-30  950  	sb->s_maxbytes = MAX_LFS_FILESIZE;
> ce72750f04d68a Sjoerd Simons     2021-11-05  951  	err = super_setup_bdi(sb);
> ce72750f04d68a Sjoerd Simons     2021-11-05  952  	if (err)
> 74ce793bcbde5c Mickaël Salaün    2023-06-12  953  		return err;
> ^1da177e4c3f41 Linus Torvalds    2005-04-16  954
> b58c4e96192ee7 Andy Shevchenko   2020-03-20  955  	/* NULL is printed as '(null)' by printf(): avoid that. */
> 2c2593890079e8 Hongbo Li         2024-05-13  956  	if (fc->source == NULL)
> 2c2593890079e8 Hongbo Li         2024-05-13  957  		host_root = "";
> 
> Uninitialized on else path
> 
> ^1da177e4c3f41 Linus Torvalds    2005-04-16  958
> 2c2593890079e8 Hongbo Li         2024-05-13  959  	fsi->host_root_path =
> 2c2593890079e8 Hongbo Li         2024-05-13 @960  		kasprintf(GFP_KERNEL, "%s/%s", root_ino, host_root);
>                                                                                                           ^^^^^^^^^
> 
> 
> 2c2593890079e8 Hongbo Li         2024-05-13  961  	if (fsi->host_root_path == NULL)
> 74ce793bcbde5c Mickaël Salaün    2023-06-12  962  		return -ENOMEM;
> 

Re: [PATCH] hostfs: convert hostfs to use the new mount api

[Dan Carpenter]

On Fri, May 17, 2024 at 07:21:09PM +0800, Hongbo Li wrote:
> Thanks for your attention, I have solved the warnings in the following patch
> (the similar title: hostfs: convert hostfs to use the new mount API):
> 
> https://lore.kernel.org/all/20240515025536.3667017-1-lihongbo22@huawei.com/
> 
> or
> 
> https://patchwork.ozlabs.org/project/linux-um/patch/20240515025536.3667017-1-lihongbo22@huawei.com/
> 
> It was strange that the kernel test robot did not send the results on the
> new patch.

With uninitialized variable warnings, quite often Smatch is not the only
or first checker to report the bug so I normally search lore to see if
it has already been fixed.  In this case there were no bug reports from
Nathan Chancelor and the second version of the patch wasn't marked as a
v2 and there was no note explaining it like:

---
v2: fixed uninitialized variable warning

So it wasn't immediately clear that it had been fixed already.
https://staticthinking.wordpress.com/2022/07/27/how-to-send-a-v2-patch/

regards,
dan carpenter

Re: [PATCH] hostfs: convert hostfs to use the new mount api

[Hongbo Li]

Thanks for replying.

I will send the new patch marked with v2 later.

regards,
Hongbo Li

On 2024/5/23 18:43, Dan Carpenter wrote:
> On Fri, May 17, 2024 at 07:21:09PM +0800, Hongbo Li wrote:
>> Thanks for your attention, I have solved the warnings in the following patch
>> (the similar title: hostfs: convert hostfs to use the new mount API):
>>
>> https://lore.kernel.org/all/20240515025536.3667017-1-lihongbo22@huawei.com/
>>
>> or
>>
>> https://patchwork.ozlabs.org/project/linux-um/patch/20240515025536.3667017-1-lihongbo22@huawei.com/
>>
>> It was strange that the kernel test robot did not send the results on the
>> new patch.
> 
> With uninitialized variable warnings, quite often Smatch is not the only
> or first checker to report the bug so I normally search lore to see if
> it has already been fixed.  In this case there were no bug reports from
> Nathan Chancelor and the second version of the patch wasn't marked as a
> v2 and there was no note explaining it like:
> 
> ---
> v2: fixed uninitialized variable warning
> 
> So it wasn't immediately clear that it had been fixed already.
> https://staticthinking.wordpress.com/2022/07/27/how-to-send-a-v2-patch/
> 
> regards,
> dan carpenter
>