From d4455faccd6cbe11ddfdbe28723a2122453b4f4e Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Thu, 6 May 2021 18:02:16 -0700 Subject: [PATCH] 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/isdn/capi/kcapi_proc.c | 1 + drivers/net/wireless/intersil/hostap/hostap_proc.c | 1 + drivers/scsi/esas2r/esas2r_main.c | 1 + fs/proc/inode.c | 14 ++------------ include/linux/proc_fs.h | 1 + tools/testing/selftests/proc/read.c | 4 +++- 6 files changed, 9 insertions(+), 13 deletions(-) diff --git a/drivers/isdn/capi/kcapi_proc.c b/drivers/isdn/capi/kcapi_proc.c index b5ed4ea145cb..77e951206809 100644 --- 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 97c270845fd1..51c847d98755 100644 --- 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 5d9eeac6717a..45ec9f16c085 100644 --- 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 bde6b6f69852..2ea8aaa7206e 100644 --- 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 000cc0533c33..069c7fd95396 100644 --- 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 b3ef9e14d6cc..35ee78dff144 100644 --- 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);