palinfo fixes

	* check for proc_mkdir() failures
	* fix buffer overrun - sizeof(format string) is *not* enough to
hold sprintf() result.
	* use proc_remove_subtree(); life's much easier with it

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 13 insertions, 64 deletions

diff --git a/arch/ia64/kernel/palinfo.c b/arch/ia64/kernel/palinfo.c
index 77597e5ea60a..79521d5499f9 100644
--- a/arch/ia64/kernel/palinfo.c
+++ b/arch/ia64/kernel/palinfo.c
@@ -849,17 +849,6 @@ static palinfo_entry_t palinfo_entries[]={
 
 #define NR_PALINFO_ENTRIES      (int) ARRAY_SIZE(palinfo_entries)
 
-/*
- * this array is used to keep track of the proc entries we create. This is
- * required in the module mode when we need to remove all entries. The procfs code
- * does not do recursion of deletion
- *
- * Notes:
- *      - +1 accounts for the cpuN directory entry in /proc/pal
- */
-#define NR_PALINFO_PROC_ENTRIES (NR_CPUS*(NR_PALINFO_ENTRIES+1))
-
-static struct proc_dir_entry *palinfo_proc_entries[NR_PALINFO_PROC_ENTRIES];
 static struct proc_dir_entry *palinfo_dir;
 
 /*
@@ -971,60 +960,32 @@ palinfo_read_entry(char *page, char **start, off_t off, int count, int *eof, voi
 static void __cpuinit
 create_palinfo_proc_entries(unsigned int cpu)
 {
-#       define CPUSTR   "cpu%d"
-
         pal_func_cpu_u_t f;
-        struct proc_dir_entry **pdir;
         struct proc_dir_entry *cpu_dir;
         int j;
-        char cpustr[sizeof(CPUSTR)];
-
-
-        /*
-         * we keep track of created entries in a depth-first order for
-         * cleanup purposes. Each entry is stored into palinfo_proc_entries
-         */
-        sprintf(cpustr,CPUSTR, cpu);
+        char cpustr[3+4+1];     /* cpu numbers are up to 4095 on itanic */
+        sprintf(cpustr, "cpu%d", cpu);
 
         cpu_dir = proc_mkdir(cpustr, palinfo_dir);
+        if (!cpu_dir)
+                return;
 
         f.req_cpu = cpu;
 
-        /*
-         * Compute the location to store per cpu entries
-         * We dont store the top level entry in this list, but
-         * remove it finally after removing all cpu entries.
-         */
-        pdir = &palinfo_proc_entries[cpu*(NR_PALINFO_ENTRIES+1)];
-        *pdir++ = cpu_dir;
         for (j=0; j < NR_PALINFO_ENTRIES; j++) {
                 f.func_id = j;
-                *pdir = create_proc_read_entry(
-                                palinfo_entries[j].name, 0, cpu_dir,
-                                palinfo_read_entry, (void *)f.value);
-                pdir++;
+                create_proc_read_entry(
+                        palinfo_entries[j].name, 0, cpu_dir,
+                        palinfo_read_entry, (void *)f.value);
         }
 }
 
 static void
 remove_palinfo_proc_entries(unsigned int hcpu)
 {
-        int j;
-        struct proc_dir_entry *cpu_dir, **pdir;
-
-        pdir = &palinfo_proc_entries[hcpu*(NR_PALINFO_ENTRIES+1)];
-        cpu_dir = *pdir;
-        *pdir++=NULL;
-        for (j=0; j < (NR_PALINFO_ENTRIES); j++) {
-                if ((*pdir)) {
-                        remove_proc_entry ((*pdir)->name, cpu_dir);
-                        *pdir ++= NULL;
-                }
-        }
-
-        if (cpu_dir) {
-                remove_proc_entry(cpu_dir->name, palinfo_dir);
-        }
+        char cpustr[3+4+1];     /* cpu numbers are up to 4095 on itanic */
+        sprintf(cpustr, "cpu%d", hcpu);
+        remove_proc_subtree(cpustr, palinfo_dir);
 }
 
 static int __cpuinit palinfo_cpu_callback(struct notifier_block *nfb,
@@ -1058,6 +1019,8 @@ palinfo_init(void)
 
         printk(KERN_INFO "PAL Information Facility v%s\n", PALINFO_VERSION);
         palinfo_dir = proc_mkdir("pal", NULL);
+        if (!palinfo_dir)
+                return -ENOMEM;
 
         /* Create palinfo dirs in /proc for all online cpus */
         for_each_online_cpu(i) {
@@ -1073,22 +1036,8 @@ palinfo_init(void)
 static void __exit
 palinfo_exit(void)
 {
-        int i = 0;
-
-        /* remove all nodes: depth first pass. Could optimize this  */
-        for_each_online_cpu(i) {
-                remove_palinfo_proc_entries(i);
-        }
-
-        /*
-         * Remove the top level entry finally
-         */
-        remove_proc_entry(palinfo_dir->name, NULL);
-
-        /*
-         * Unregister from cpu notifier callbacks
-         */
         unregister_hotcpu_notifier(&palinfo_cpu_notifier);
+        remove_proc_subtree("pal", NULL);
 }
 
 module_init(palinfo_init);