Implement ->proc_write_buf() so procfs copies in what is written before it pins the entry, and parse the command from that copy. Commands longer than PAGE_SIZE - 1 bytes are rejected now instead of cut at 64k.
Signed-off-by: Christian Brauner (Amutable) <[email protected]> --- drivers/s390/block/dasd_proc.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/drivers/s390/block/dasd_proc.c b/drivers/s390/block/dasd_proc.c index 86399427f01d..6c3bbb7dfe85 100644 --- a/drivers/s390/block/dasd_proc.c +++ b/drivers/s390/block/dasd_proc.c @@ -15,7 +15,6 @@ #include <linux/slab.h> #include <linux/string.h> #include <linux/seq_file.h> -#include <linux/vmalloc.h> #include <linux/proc_fs.h> #include <asm/debug.h> @@ -247,17 +246,15 @@ static int dasd_stats_proc_show(struct seq_file *m, void *v) } static ssize_t dasd_stats_proc_write(struct file *file, - const char __user *user_buf, size_t user_len, loff_t *pos) + char *buffer, size_t user_len, loff_t *pos) { #ifdef CONFIG_DASD_PROFILE - char *buffer, *str; + char *str; int rc; - if (user_len > 65536) - user_len = 65536; - buffer = dasd_get_user_string(user_buf, user_len); - if (IS_ERR(buffer)) - return PTR_ERR(buffer); + /* strip linefeed */ + if (user_len && buffer[user_len - 1] == '\n') + buffer[user_len - 1] = 0; /* check for valid verbs */ str = skip_spaces(buffer); @@ -296,13 +293,11 @@ static ssize_t dasd_stats_proc_write(struct file *file, pr_info("The statistics have been reset\n"); } else goto out_parse_error; - vfree(buffer); return user_len; out_parse_error: rc = -EINVAL; pr_warn("%s is not a supported value for /proc/dasd/statistics\n", str); out_error: - vfree(buffer); return rc; #else pr_warn("/proc/dasd/statistics: is not activated in this kernel\n"); @@ -312,7 +307,7 @@ out_error: static const struct proc_ops dasd_stats_proc_ops = { .proc_show = dasd_stats_proc_show, - .proc_write = dasd_stats_proc_write, + .proc_write_buf = dasd_stats_proc_write, }; /* -- 2.53.0
