LU-13783 libcfs: don't depend on sysctl support for debugfs

Since Linux v5.8-rc1~55^2~6 sysctl support routines like
proc_dointvec() expect a pointer to kernel-space, not userspace.

So stop using these function for debugfs files, and instead
provide bespoke functions.

Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I340a748bbfbd066054a73299ce32698aa39a0e2d
Reviewed-on: https://review.whamcloud.com/40832
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/libcfs/include/libcfs/libcfs.h b/libcfs/include/libcfs/libcfs.h
index 82a3920..554c680 100644 (file)
--- a/libcfs/include/libcfs/libcfs.h
+++ b/libcfs/include/libcfs/libcfs.h
@@ -99,6 +99,8 @@ int lprocfs_call_handler(void *data, int write, loff_t *ppos,
                         void __user *buffer, size_t *lenp,
                         int (*handler)(void *data, int write, loff_t pos,
                                        void __user *buffer, int len));
+int debugfs_doint(struct ctl_table *table, int write,
+                 void __user *buffer, size_t *lenp, loff_t *ppos);
 
 /*
  * Memory

diff --git a/libcfs/libcfs/module.c b/libcfs/libcfs/module.c
index 583a1fb..1e5f6f1 100644 (file)
--- a/libcfs/libcfs/module.c
+++ b/libcfs/libcfs/module.c
@@ -388,7 +388,31 @@ static int proc_fail_loc(struct ctl_table *table, int write,
        int rc;
        long old_fail_loc = cfs_fail_loc;
 
-       rc = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
+       if (!*lenp || *ppos) {
+               *lenp = 0;
+               return 0;
+       }
+
+       if (write) {
+               char *kbuf = memdup_user_nul(buffer, *lenp);
+
+               if (IS_ERR(kbuf))
+                       return PTR_ERR(kbuf);
+               rc = kstrtoul(kbuf, 0, &cfs_fail_loc);
+               kfree(kbuf);
+               *ppos += *lenp;
+       } else {
+               char kbuf[64/3+3];
+
+               rc = scnprintf(kbuf, sizeof(kbuf), "%lu\n", cfs_fail_loc);
+               if (copy_to_user(buffer, kbuf, rc))
+                       rc = -EFAULT;
+               else {
+                       *lenp = rc;
+                       *ppos += rc;
+               }
+       }
+
        if (old_fail_loc != cfs_fail_loc) {
                cfs_race_state = 1;
                wake_up(&cfs_race_waitq);
@@ -396,6 +420,119 @@ static int proc_fail_loc(struct ctl_table *table, int write,
        return rc;
 }
 
+int debugfs_doint(struct ctl_table *table, int write,
+                 void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+       int rc;
+
+       if (!*lenp || *ppos) {
+               *lenp = 0;
+               return 0;
+       }
+
+       if (write) {
+               char *kbuf = memdup_user_nul(buffer, *lenp);
+               int val;
+
+               if (IS_ERR(kbuf))
+                       return PTR_ERR(kbuf);
+
+               rc = kstrtoint(kbuf, 0, &val);
+               kfree(kbuf);
+               if (!rc) {
+                       if (table->extra1 && val < *(int *)table->extra1)
+                               val = *(int *)table->extra1;
+                       if (table->extra2 && val > *(int *)table->extra2)
+                               val = *(int *)table->extra2;
+                       *(int *)table->data = val;
+               }
+               *ppos += *lenp;
+       } else {
+               char kbuf[64/3+3];
+
+               rc = scnprintf(kbuf, sizeof(kbuf), "%u\n", *(int *)table->data);
+               if (copy_to_user(buffer, kbuf, rc))
+                       rc = -EFAULT;
+               else {
+                       *lenp = rc;
+                       *ppos += rc;
+               }
+       }
+
+       return rc;
+}
+EXPORT_SYMBOL(debugfs_doint);
+
+static int debugfs_dou64(struct ctl_table *table, int write,
+                        void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+       int rc;
+
+       if (!*lenp || *ppos) {
+               *lenp = 0;
+               return 0;
+       }
+
+       if (write) {
+               char *kbuf = memdup_user_nul(buffer, *lenp);
+               unsigned long long val;
+
+               if (IS_ERR(kbuf))
+                       return PTR_ERR(kbuf);
+
+               rc = kstrtoull(kbuf, 0, &val);
+               kfree(kbuf);
+               if (!rc)
+                       *(u64 *)table->data = val;
+               *ppos += *lenp;
+       } else {
+               char kbuf[64/3+3];
+
+               rc = scnprintf(kbuf, sizeof(kbuf), "%llu\n",
+                              (unsigned long long)*(u64 *)table->data);
+               if (copy_to_user(buffer, kbuf, rc))
+                       rc = -EFAULT;
+               else {
+                       *lenp = rc;
+                       *ppos += rc;
+               }
+       }
+
+       return rc;
+}
+
+static int debugfs_dostring(struct ctl_table *table, int write,
+                           void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+       int len = *lenp;
+       char *kbuf = table->data;
+
+       if (!len || *ppos) {
+               *lenp = 0;
+               return 0;
+       }
+       if (len > table->maxlen)
+               len = table->maxlen;
+       if (write) {
+               if (copy_from_user(kbuf, buffer, len))
+                       return -EFAULT;
+               memset(kbuf+len, 0, table->maxlen - len);
+               *ppos = *lenp;
+       } else {
+               len = strnlen(kbuf, len);
+               if (copy_to_user(buffer, kbuf, len))
+                       return -EFAULT;
+               if (len < *lenp) {
+                       if (copy_to_user(buffer+len, "\n", 1))
+                               return -EFAULT;
+                       len += 1;
+               }
+               *ppos += len;
+               *lenp -= len;
+       }
+       return len;
+}
+
 static int __proc_cpt_table(void *data, int write,
                            loff_t pos, void __user *buffer, int nob)
 {
@@ -527,21 +664,21 @@ static struct ctl_table lnet_table[] = {
                .data           = lnet_debug_log_upcall,
                .maxlen         = sizeof(lnet_debug_log_upcall),
                .mode           = 0644,
-               .proc_handler   = &proc_dostring,
+               .proc_handler   = &debugfs_dostring,
        },
        {
                .procname       = "lnet_memused",
                .data           = (u64 *)&libcfs_kmem.counter,
                .maxlen         = sizeof(u64),
                .mode           = 0444,
-               .proc_handler   = &proc_doulongvec_minmax,
+               .proc_handler   = &debugfs_dou64,
        },
        {
                .procname       = "catastrophe",
                .data           = &libcfs_catastrophe,
                .maxlen         = sizeof(int),
                .mode           = 0444,
-               .proc_handler   = &proc_dointvec,
+               .proc_handler   = &debugfs_doint,
        },
        {
                .procname       = "dump_kernel",
@@ -560,7 +697,7 @@ static struct ctl_table lnet_table[] = {
                .data           = &libcfs_watchdog_ratelimit,
                .maxlen         = sizeof(int),
                .mode           = 0644,
-               .proc_handler   = &proc_dointvec_minmax,
+               .proc_handler   = &debugfs_doint,
                .extra1         = &min_watchdog_ratelimit,
                .extra2         = &max_watchdog_ratelimit,
        },
@@ -583,14 +720,14 @@ static struct ctl_table lnet_table[] = {
                .data           = &cfs_fail_val,
                .maxlen         = sizeof(int),
                .mode           = 0644,
-               .proc_handler   = &proc_dointvec
+               .proc_handler   = &debugfs_doint
        },
        {
                .procname       = "fail_err",
                .data           = &cfs_fail_err,
                .maxlen         = sizeof(cfs_fail_err),
                .mode           = 0644,
-               .proc_handler   = &proc_dointvec,
+               .proc_handler   = &debugfs_doint,
        },
        {
        }

diff --git a/lnet/lnet/router_proc.c b/lnet/lnet/router_proc.c
index 4f42ea3..4a5952e 100644 (file)
--- a/lnet/lnet/router_proc.c
+++ b/lnet/lnet/router_proc.c
@@ -902,7 +902,7 @@ static struct ctl_table lnet_table[] = {
                .data           = &lnet_lnd_timeout,
                .maxlen         = sizeof(lnet_lnd_timeout),
                .mode           = 0444,
-               .proc_handler   = &proc_dointvec,
+               .proc_handler   = &debugfs_doint,
        },
        { .procname = NULL }
 };