| Message ID | 20180425154827.32251-35-hch@lst.de (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
Christoph Hellwig <hch@lst.de> writes: > Use remove_proc_subtree to remove the whole subtree on cleanup, and > unwind the registration loop into individual calls. Switch to use > proc_create_seq where applicable. Can you please explain why you are removing the error handling when you are unwinding the registration loop? > int __init atm_proc_init(void) > { > - static struct atm_proc_entry *e; > - int ret; > - > atm_proc_root = proc_net_mkdir(&init_net, "atm", init_net.proc_net); > if (!atm_proc_root) > - goto err_out; > - for (e = atm_proc_ents; e->name; e++) { > - struct proc_dir_entry *dirent; > - > - dirent = proc_create(e->name, 0444, > - atm_proc_root, e->proc_fops); > - if (!dirent) > - goto err_out_remove; > - e->dirent = dirent; > - } > - ret = 0; > -out: > - return ret; > - > -err_out_remove: > - atm_proc_dirs_remove(); > -err_out: > - ret = -ENOMEM; > - goto out; > + return -ENOMEM; > + proc_create_seq("devices", 0444, atm_proc_root, &atm_dev_seq_ops); > + proc_create("pvc", 0444, atm_proc_root, &pvc_seq_fops); > + proc_create("svc", 0444, atm_proc_root, &svc_seq_fops); > + proc_create("vc", 0444, atm_proc_root, &vcc_seq_fops); > + return 0; > } These proc entries could fail to register with -ENOMEM if for no other reason. Can you justify the removal of the error handling? Can you please at least mention that removal in your change description and explain why it is reasonable. As it sits this is not a semantics preserving transformation, and the difference is not documented. Which raises red flags for me. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, May 05, 2018 at 07:51:18AM -0500, Eric W. Biederman wrote: > Christoph Hellwig <hch@lst.de> writes: > > > Use remove_proc_subtree to remove the whole subtree on cleanup, and > > unwind the registration loop into individual calls. Switch to use > > proc_create_seq where applicable. > > Can you please explain why you are removing the error handling when > you are unwinding the registration loop? Because there is no point in handling these errors. The code work perfectly fine without procfs, or without given proc files and the removal works just fine if they don't exist either. This is a very common patter in various parts of the kernel already. I'll document it better in the changelog. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Christoph Hellwig <hch@lst.de> writes: > On Sat, May 05, 2018 at 07:51:18AM -0500, Eric W. Biederman wrote: >> Christoph Hellwig <hch@lst.de> writes: >> >> > Use remove_proc_subtree to remove the whole subtree on cleanup, and >> > unwind the registration loop into individual calls. Switch to use >> > proc_create_seq where applicable. >> >> Can you please explain why you are removing the error handling when >> you are unwinding the registration loop? > > Because there is no point in handling these errors. The code work > perfectly fine without procfs, or without given proc files and the > removal works just fine if they don't exist either. This is a very > common patter in various parts of the kernel already. > > I'll document it better in the changelog. Thank you. That is the kind of thing that could be a signal of inattentiveness and problems, especially when it is not documented. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/atm/proc.c b/net/atm/proc.c index 55410c00c7e2..f272b0f59d82 100644 --- a/net/atm/proc.c +++ b/net/atm/proc.c @@ -257,18 +257,6 @@ static const struct seq_operations atm_dev_seq_ops = { .show = atm_dev_seq_show, }; -static int atm_dev_seq_open(struct inode *inode, struct file *file) -{ - return seq_open(file, &atm_dev_seq_ops); -} - -static const struct file_operations devices_seq_fops = { - .open = atm_dev_seq_open, - .read = seq_read, - .llseek = seq_lseek, - .release = seq_release, -}; - static int pvc_seq_show(struct seq_file *seq, void *v) { static char atm_pvc_banner[] = @@ -440,58 +428,19 @@ void atm_proc_dev_deregister(struct atm_dev *dev) kfree(dev->proc_name); } -static struct atm_proc_entry { - char *name; - const struct file_operations *proc_fops; - struct proc_dir_entry *dirent; -} atm_proc_ents[] = { - { .name = "devices", .proc_fops = &devices_seq_fops }, - { .name = "pvc", .proc_fops = &pvc_seq_fops }, - { .name = "svc", .proc_fops = &svc_seq_fops }, - { .name = "vc", .proc_fops = &vcc_seq_fops }, - { .name = NULL, .proc_fops = NULL } -}; - -static void atm_proc_dirs_remove(void) -{ - static struct atm_proc_entry *e; - - for (e = atm_proc_ents; e->name; e++) { - if (e->dirent) - remove_proc_entry(e->name, atm_proc_root); - } - remove_proc_entry("atm", init_net.proc_net); -} - int __init atm_proc_init(void) { - static struct atm_proc_entry *e; - int ret; - atm_proc_root = proc_net_mkdir(&init_net, "atm", init_net.proc_net); if (!atm_proc_root) - goto err_out; - for (e = atm_proc_ents; e->name; e++) { - struct proc_dir_entry *dirent; - - dirent = proc_create(e->name, 0444, - atm_proc_root, e->proc_fops); - if (!dirent) - goto err_out_remove; - e->dirent = dirent; - } - ret = 0; -out: - return ret; - -err_out_remove: - atm_proc_dirs_remove(); -err_out: - ret = -ENOMEM; - goto out; + return -ENOMEM; + proc_create_seq("devices", 0444, atm_proc_root, &atm_dev_seq_ops); + proc_create("pvc", 0444, atm_proc_root, &pvc_seq_fops); + proc_create("svc", 0444, atm_proc_root, &svc_seq_fops); + proc_create("vc", 0444, atm_proc_root, &vcc_seq_fops); + return 0; } void atm_proc_exit(void) { - atm_proc_dirs_remove(); + remove_proc_subtree("atm", init_net.proc_net); }
Use remove_proc_subtree to remove the whole subtree on cleanup, and unwind the registration loop into individual calls. Switch to use proc_create_seq where applicable. Signed-off-by: Christoph Hellwig <hch@lst.de> --- net/atm/proc.c | 65 ++++++-------------------------------------------- 1 file changed, 7 insertions(+), 58 deletions(-)