block: IBM RamSan 70/80 fixes inconsistent locking.

This patch includes changes to the cregs locking scheme. Before,
inconsistant locking would occur because of misuse of spin_lock,
spin_lock_bh, and counter parts.

Signed-off-by: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/rsxx/cregs.c b/drivers/block/rsxx/cregs.c
index 2241564..0539a25 100644 (file)
--- a/drivers/block/rsxx/cregs.c
+++ b/drivers/block/rsxx/cregs.c
@@ -99,22 +99,6 @@ static void copy_from_creg_data(struct rsxx_cardinfo *card,
        }
 }
 
-static struct creg_cmd *pop_active_cmd(struct rsxx_cardinfo *card)
-{
-       struct creg_cmd *cmd;
-
-       /*
-        * Spin lock is needed because this can be called in atomic/interrupt
-        * context.
-        */
-       spin_lock_bh(&card->creg_ctrl.lock);
-       cmd = card->creg_ctrl.active_cmd;
-       card->creg_ctrl.active_cmd = NULL;
-       spin_unlock_bh(&card->creg_ctrl.lock);
-
-       return cmd;
-}
-
 static void creg_issue_cmd(struct rsxx_cardinfo *card, struct creg_cmd *cmd)
 {
        iowrite32(cmd->addr, card->regmap + CREG_ADD);
@@ -189,11 +173,11 @@ static int creg_queue_cmd(struct rsxx_cardinfo *card,
        cmd->cb_private = cb_private;
        cmd->status     = 0;
 
-       spin_lock(&card->creg_ctrl.lock);
+       spin_lock_bh(&card->creg_ctrl.lock);
        list_add_tail(&cmd->list, &card->creg_ctrl.queue);
        card->creg_ctrl.q_depth++;
        creg_kick_queue(card);
-       spin_unlock(&card->creg_ctrl.lock);
+       spin_unlock_bh(&card->creg_ctrl.lock);
 
        return 0;
 }
@@ -203,7 +187,11 @@ static void creg_cmd_timed_out(unsigned long data)
        struct rsxx_cardinfo *card = (struct rsxx_cardinfo *) data;
        struct creg_cmd *cmd;
 
-       cmd = pop_active_cmd(card);
+       spin_lock(&card->creg_ctrl.lock);
+       cmd = card->creg_ctrl.active_cmd;
+       card->creg_ctrl.active_cmd = NULL;
+       spin_unlock(&card->creg_ctrl.lock);
+
        if (cmd == NULL) {
                card->creg_ctrl.creg_stats.creg_timeout++;
                dev_warn(CARD_TO_DEV(card),
@@ -240,7 +228,11 @@ static void creg_cmd_done(struct work_struct *work)
        if (del_timer_sync(&card->creg_ctrl.cmd_timer) == 0)
                card->creg_ctrl.creg_stats.failed_cancel_timer++;
 
-       cmd = pop_active_cmd(card);
+       spin_lock_bh(&card->creg_ctrl.lock);
+       cmd = card->creg_ctrl.active_cmd;
+       card->creg_ctrl.active_cmd = NULL;
+       spin_unlock_bh(&card->creg_ctrl.lock);
+
        if (cmd == NULL) {
                dev_err(CARD_TO_DEV(card),
                        "Spurious creg interrupt!\n");
@@ -289,10 +281,10 @@ creg_done:
 
        kmem_cache_free(creg_cmd_pool, cmd);
 
-       spin_lock(&card->creg_ctrl.lock);
+       spin_lock_bh(&card->creg_ctrl.lock);
        card->creg_ctrl.active = 0;
        creg_kick_queue(card);
-       spin_unlock(&card->creg_ctrl.lock);
+       spin_unlock_bh(&card->creg_ctrl.lock);
 }
 
 static void creg_reset(struct rsxx_cardinfo *card)
@@ -317,7 +309,7 @@ static void creg_reset(struct rsxx_cardinfo *card)
                "Resetting creg interface for recovery\n");
 
        /* Cancel outstanding commands */
-       spin_lock(&card->creg_ctrl.lock);
+       spin_lock_bh(&card->creg_ctrl.lock);
        list_for_each_entry_safe(cmd, tmp, &card->creg_ctrl.queue, list) {
                list_del(&cmd->list);
                card->creg_ctrl.q_depth--;
@@ -338,7 +330,7 @@ static void creg_reset(struct rsxx_cardinfo *card)
 
                card->creg_ctrl.active = 0;
        }
-       spin_unlock(&card->creg_ctrl.lock);
+       spin_unlock_bh(&card->creg_ctrl.lock);
 
        card->creg_ctrl.reset = 0;
        spin_lock_irqsave(&card->irq_lock, flags);
@@ -705,7 +697,7 @@ void rsxx_creg_destroy(struct rsxx_cardinfo *card)
        int cnt = 0;
 
        /* Cancel outstanding commands */
-       spin_lock(&card->creg_ctrl.lock);
+       spin_lock_bh(&card->creg_ctrl.lock);
        list_for_each_entry_safe(cmd, tmp, &card->creg_ctrl.queue, list) {
                list_del(&cmd->list);
                if (cmd->cb)
@@ -730,7 +722,7 @@ void rsxx_creg_destroy(struct rsxx_cardinfo *card)
                        "Canceled active creg command\n");
                kmem_cache_free(creg_cmd_pool, cmd);
        }
-       spin_unlock(&card->creg_ctrl.lock);
+       spin_unlock_bh(&card->creg_ctrl.lock);
 
        cancel_work_sync(&card->creg_ctrl.done_work);
 }