s390/dasd: add locking for global_profile access

Access to DASDs global statistics is done without locking which
can lead to inconsistent data. Add locking to fix this. Also move
the relevant structs in a global dasd_profile struct.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 24 insertions, 14 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 4abf11965484..a67e8dae73c3 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -674,8 +674,12 @@ EXPORT_SYMBOL(dasd_enable_device);
 unsigned int dasd_global_profile_level = DASD_PROFILE_OFF;
 
 #ifdef CONFIG_DASD_PROFILE
-struct dasd_profile_info dasd_global_profile_data;
-static struct dentry *dasd_global_profile_dentry;
+static struct dasd_profile_info dasd_global_profile_data;
+struct dasd_profile dasd_global_profile = {
+        .dentry = NULL,
+        .data = &dasd_global_profile_data,
+        .lock = __SPIN_LOCK_UNLOCKED(dasd_global_profile.lock),
+};
 static struct dentry *dasd_debugfs_global_entry;
 
 /*
@@ -696,11 +700,13 @@ static void dasd_profile_start(struct dasd_block *block,
                         if (++counter >= 31)
                                 break;
 
+        spin_lock(&dasd_global_profile.lock);
         if (dasd_global_profile_level) {
-                dasd_global_profile_data.dasd_io_nr_req[counter]++;
+                dasd_global_profile.data->dasd_io_nr_req[counter]++;
                 if (rq_data_dir(req) == READ)
-                        dasd_global_profile_data.dasd_read_nr_req[counter]++;
+                        dasd_global_profile.data->dasd_read_nr_req[counter]++;
         }
+        spin_unlock(&dasd_global_profile.lock);
 
         spin_lock(&block->profile.lock);
         if (block->profile.data) {
@@ -825,8 +831,9 @@ static void dasd_profile_end(struct dasd_block *block,
         dasd_profile_counter(irqtime / sectors, irqtimeps_ind);
         dasd_profile_counter(endtime, endtime_ind);
 
+        spin_lock(&dasd_global_profile.lock);
         if (dasd_global_profile_level) {
-                dasd_profile_end_add_data(&dasd_global_profile_data,
+                dasd_profile_end_add_data(dasd_global_profile.data,
                                           cqr->startdev != block->base,
                                           cqr->cpmode == 1,
                                           rq_data_dir(req) == READ,
@@ -835,6 +842,7 @@ static void dasd_profile_end(struct dasd_block *block,
                                           irqtime_ind, irqtimeps_ind,
                                           endtime_ind);
         }
+        spin_unlock(&dasd_global_profile.lock);
 
         spin_lock(&block->profile.lock);
         if (block->profile.data)
@@ -878,8 +886,7 @@ void dasd_profile_reset(struct dasd_profile *profile)
 
 void dasd_global_profile_reset(void)
 {
-        memset(&dasd_global_profile_data, 0, sizeof(dasd_global_profile_data));
-        getnstimeofday(&dasd_global_profile_data.starttod);
+        dasd_profile_reset(&dasd_global_profile);
 }
 
 int dasd_profile_on(struct dasd_profile *profile)
@@ -1077,7 +1084,9 @@ static int dasd_stats_global_show(struct seq_file *m, void *v)
                 seq_puts(m, "disabled\n");
                 return 0;
         }
-        dasd_stats_seq_print(m, &dasd_global_profile_data);
+        spin_lock_bh(&dasd_global_profile.lock);
+        dasd_stats_seq_print(m, dasd_global_profile.data);
+        spin_unlock_bh(&dasd_global_profile.lock);
         return 0;
 }
 
@@ -1123,8 +1132,8 @@ static void dasd_profile_exit(struct dasd_profile *profile)
 static void dasd_statistics_removeroot(void)
 {
         dasd_global_profile_level = DASD_PROFILE_OFF;
-        debugfs_remove(dasd_global_profile_dentry);
-        dasd_global_profile_dentry = NULL;
+        debugfs_remove(dasd_global_profile.dentry);
+        dasd_global_profile.dentry = NULL;
         debugfs_remove(dasd_debugfs_global_entry);
         debugfs_remove(dasd_debugfs_root_entry);
 }
@@ -1136,7 +1145,6 @@ static void dasd_statistics_createroot(void)
 
         dasd_debugfs_root_entry = NULL;
         dasd_debugfs_global_entry = NULL;
-        dasd_global_profile_dentry = NULL;
         pde = debugfs_create_dir("dasd", NULL);
         if (!pde || IS_ERR(pde))
                 goto error;
@@ -1151,7 +1159,7 @@ static void dasd_statistics_createroot(void)
                                   NULL, &dasd_stats_global_fops);
         if (!pde || IS_ERR(pde))
                 goto error;
-        dasd_global_profile_dentry = pde;
+        dasd_global_profile.dentry = pde;
         return;
 
 error:
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index 8b5d4100abf7..91731fa05604 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -651,7 +651,7 @@ dasd_check_blocksize(int bsize)
 #define DASD_PROFILE_GLOBAL_ONLY 2
 
 extern debug_info_t *dasd_debug_area;
-extern struct dasd_profile_info dasd_global_profile_data;
+extern struct dasd_profile dasd_global_profile;
 extern unsigned int dasd_global_profile_level;
 extern const struct block_device_operations dasd_device_operations;
 
diff --git a/drivers/s390/block/dasd_proc.c b/drivers/s390/block/dasd_proc.c
index 78ac905a5b7f..76410084c48f 100644
--- a/drivers/s390/block/dasd_proc.c
+++ b/drivers/s390/block/dasd_proc.c
@@ -219,7 +219,8 @@ static int dasd_stats_proc_show(struct seq_file *m, void *v)
                                     "/proc/dasd/statistics'\n");
                 return 0;
         }
-        prof = &dasd_global_profile_data;
+        spin_lock_bh(&dasd_global_profile.lock);
+        prof = dasd_global_profile.data;
 
         /* prevent counter 'overflow' on output */
         for (factor = 1; (prof->dasd_io_reqs / factor) > 9999999;
@@ -255,6 +256,7 @@ static int dasd_stats_proc_show(struct seq_file *m, void *v)
         dasd_statistics_array(m, prof->dasd_io_time3, factor);
         seq_printf(m, "# of req in chanq at enqueuing (1..32) \n");
         dasd_statistics_array(m, prof->dasd_io_nr_req, factor);
+        spin_unlock_bh(&dasd_global_profile.lock);
 #else
         seq_printf(m, "Statistics are not activated in this kernel\n");
 #endif