proc: mandate ->proc_lseek in "struct proc_ops"

Now that proc_ops are separate from file_operations and other operations
it easy to check all instances to have ->proc_lseek hook and remove check
in main code.

Note:
nonseekable_open() files naturally don't require ->proc_lseek.

Garbage collect pde_lseek() function.

[adobriyan@gmail.com: smoke test lseek()]
Link: https://lkml.kernel.org/r/YG4OIhChOrVTPgdN@localhost.localdomain
Link: https://lkml.kernel.org/r/YFYX0Bzwxlc7aBa/@localhost.localdomain
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/isdn/capi/kcapi_proc.c b/drivers/isdn/capi/kcapi_proc.c
index b5ed4ea..77e9512 100644 (file)
--- a/drivers/isdn/capi/kcapi_proc.c
+++ b/drivers/isdn/capi/kcapi_proc.c
@@ -201,6 +201,7 @@ static ssize_t empty_read(struct file *file, char __user *buf,
 
 static const struct proc_ops empty_proc_ops = {
        .proc_read      = empty_read,
+       .proc_lseek     = default_llseek,
 };
 
 // ---------------------------------------------------------------------------

diff --git a/drivers/net/wireless/intersil/hostap/hostap_proc.c b/drivers/net/wireless/intersil/hostap/hostap_proc.c
index 97c2708..51c847d 100644 (file)
--- a/drivers/net/wireless/intersil/hostap/hostap_proc.c
+++ b/drivers/net/wireless/intersil/hostap/hostap_proc.c
@@ -227,6 +227,7 @@ static ssize_t prism2_aux_dump_proc_no_read(struct file *file, char __user *buf,
 
 static const struct proc_ops prism2_aux_dump_proc_ops = {
        .proc_read      = prism2_aux_dump_proc_no_read,
+       .proc_lseek     = default_llseek,
 };
 
 

diff --git a/drivers/scsi/esas2r/esas2r_main.c b/drivers/scsi/esas2r/esas2r_main.c
index 5d9eeac..45ec9f1 100644 (file)
--- a/drivers/scsi/esas2r/esas2r_main.c
+++ b/drivers/scsi/esas2r/esas2r_main.c
@@ -616,6 +616,7 @@ static const struct file_operations esas2r_proc_fops = {
 };
 
 static const struct proc_ops esas2r_proc_ops = {
+       .proc_lseek             = default_llseek,
        .proc_ioctl             = esas2r_proc_ioctl,
 #ifdef CONFIG_COMPAT
        .proc_compat_ioctl      = compat_ptr_ioctl,

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index bde6b6f..2ea8aaa 100644 (file)
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -273,25 +273,15 @@ void proc_entry_rundown(struct proc_dir_entry *de)
        spin_unlock(&de->pde_unload_lock);
 }
 
-static loff_t pde_lseek(struct proc_dir_entry *pde, struct file *file, loff_t offset, int whence)
-{
-       typeof_member(struct proc_ops, proc_lseek) lseek;
-
-       lseek = pde->proc_ops->proc_lseek;
-       if (!lseek)
-               lseek = default_llseek;
-       return lseek(file, offset, whence);
-}
-
 static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
 {
        struct proc_dir_entry *pde = PDE(file_inode(file));
        loff_t rv = -EINVAL;
 
        if (pde_is_permanent(pde)) {
-               return pde_lseek(pde, file, offset, whence);
+               return pde->proc_ops->proc_lseek(file, offset, whence);
        } else if (use_pde(pde)) {
-               rv = pde_lseek(pde, file, offset, whence);
+               rv = pde->proc_ops->proc_lseek(file, offset, whence);
                unuse_pde(pde);
        }
        return rv;

diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 000cc05..069c7fd 100644 (file)
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -32,6 +32,7 @@ struct proc_ops {
        ssize_t (*proc_read)(struct file *, char __user *, size_t, loff_t *);
        ssize_t (*proc_read_iter)(struct kiocb *, struct iov_iter *);
        ssize_t (*proc_write)(struct file *, const char __user *, size_t, loff_t *);
+       /* mandatory unless nonseekable_open() or equivalent is used */
        loff_t  (*proc_lseek)(struct file *, loff_t, int);
        int     (*proc_release)(struct inode *, struct file *);
        __poll_t (*proc_poll)(struct file *, struct poll_table_struct *);

diff --git a/tools/testing/selftests/proc/read.c b/tools/testing/selftests/proc/read.c
index b3ef9e1..35ee78d 100644 (file)
--- a/tools/testing/selftests/proc/read.c
+++ b/tools/testing/selftests/proc/read.c
@@ -14,7 +14,7 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 // Test
-// 1) read of every file in /proc
+// 1) read and lseek on every file in /proc
 // 2) readlink of every symlink in /proc
 // 3) recursively (1) + (2) for every directory in /proc
 // 4) write to /proc/*/clear_refs and /proc/*/task/*/clear_refs
@@ -45,6 +45,8 @@ static void f_reg(DIR *d, const char *filename)
        fd = openat(dirfd(d), filename, O_RDONLY|O_NONBLOCK);
        if (fd == -1)
                return;
+       /* struct proc_ops::proc_lseek is mandatory if file is seekable. */
+       (void)lseek(fd, 0, SEEK_SET);
        rv = read(fd, buf, sizeof(buf));
        assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);
        close(fd);