cciss: clean up interrupt handler

Simplify the interrupt handler code to more closely match hpsa and to
hopefully make it easier to follow.

Signed-off-by: Mike Miller <mike.miller@hp.com>
Cc: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 141 insertions, 95 deletions

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 6db790c2802f..cae6a1383282 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -167,7 +167,8 @@ static DEFINE_MUTEX(scan_mutex);
 static LIST_HEAD(scan_q);
 
 static void do_cciss_request(struct request_queue *q);
-static irqreturn_t do_cciss_intr(int irq, void *dev_id);
+static irqreturn_t do_cciss_intx(int irq, void *dev_id);
+static irqreturn_t do_cciss_msix_intr(int irq, void *dev_id);
 static int cciss_open(struct block_device *bdev, fmode_t mode);
 static int cciss_release(struct gendisk *disk, fmode_t mode);
 static int cciss_ioctl(struct block_device *bdev, fmode_t mode,
@@ -197,7 +198,6 @@ static int sendcmd_withirq_core(ctlr_info_t *h, CommandList_struct *c,
         int attempt_retry);
 static int process_sendcmd_error(ctlr_info_t *h, CommandList_struct *c);
 
-static void fail_all_cmds(unsigned long ctlr);
 static int add_to_scan_list(struct ctlr_info *h);
 static int scan_thread(void *data);
 static int check_for_unit_attention(ctlr_info_t *h, CommandList_struct *c);
@@ -3124,6 +3124,34 @@ after_error_processing:
         blk_complete_request(cmd->rq);
 }
 
+static inline u32 cciss_tag_contains_index(u32 tag)
+{
+#define DIRECT_LOOKUP_BIT 0x04
+        return tag & DIRECT_LOOKUP_BIT;
+}
+
+static inline u32 cciss_tag_to_index(u32 tag)
+{
+#define DIRECT_LOOKUP_SHIFT 3
+        return tag >> DIRECT_LOOKUP_SHIFT;
+}
+
+static inline u32 cciss_tag_discard_error_bits(u32 tag)
+{
+#define CCISS_ERROR_BITS 0x03
+        return tag & ~CCISS_ERROR_BITS;
+}
+
+static inline void cciss_mark_tag_indexed(u32 *tag)
+{
+        *tag |= DIRECT_LOOKUP_BIT;
+}
+
+static inline void cciss_set_tag_index(u32 *tag, u32 index)
+{
+        *tag |= (index << DIRECT_LOOKUP_SHIFT);
+}
+
 /*
  * Get a request and submit it to the controller.
  */
@@ -3172,8 +3200,8 @@ static void do_cciss_request(struct request_queue *q)
         /* got command from pool, so use the command block index instead */
         /* for direct lookups. */
         /* The first 2 bits are reserved for controller error reporting. */
-        c->Header.Tag.lower = (c->cmdindex << 3);
-        c->Header.Tag.lower |= 0x04;    /* flag for direct lookup. */
+        cciss_set_tag_index(&c->Header.Tag.lower, c->cmdindex);
+        cciss_mark_tag_indexed(&c->Header.Tag.lower);
         memcpy(&c->Header.LUN, drv->LunID, sizeof(drv->LunID));
         c->Request.CDBLen = 10; /* 12 byte commands not in FW yet; */
         c->Request.Type.Type = TYPE_CMD;        /* It is a command. */
@@ -3306,15 +3334,73 @@ static inline int interrupt_pending(ctlr_info_t *h)
 static inline long interrupt_not_for_us(ctlr_info_t *h)
 {
         return (((h->access.intr_pending(h) == 0) ||
-                 (h->interrupts_enabled == 0)));
+                (h->interrupts_enabled == 0)));
 }
 
-static irqreturn_t do_cciss_intr(int irq, void *dev_id)
+static inline int bad_tag(ctlr_info_t *h, u32 tag_index,
+                        u32 raw_tag)
 {
-        ctlr_info_t *h = dev_id;
+        if (unlikely(tag_index >= h->nr_cmds)) {
+                dev_warn(&h->pdev->dev, "bad tag 0x%08x ignored.\n", raw_tag);
+                return 1;
+        }
+        return 0;
+}
+
+static inline void finish_cmd(ctlr_info_t *h, CommandList_struct *c,
+                                u32 raw_tag)
+{
+        removeQ(c);
+        if (likely(c->cmd_type == CMD_RWREQ))
+                complete_command(h, c, 0);
+        else if (c->cmd_type == CMD_IOCTL_PEND)
+                complete(c->waiting);
+#ifdef CONFIG_CISS_SCSI_TAPE
+        else if (c->cmd_type == CMD_SCSI)
+                complete_scsi_command(c, 0, raw_tag);
+#endif
+}
+
+/* process completion of an indexed ("direct lookup") command */
+static inline u32 process_indexed_cmd(ctlr_info_t *h, u32 raw_tag)
+{
+        u32 tag_index;
         CommandList_struct *c;
+
+        tag_index = cciss_tag_to_index(raw_tag);
+        if (bad_tag(h, tag_index, raw_tag))
+                return get_next_completion(h);
+        c = h->cmd_pool + tag_index;
+        finish_cmd(h, c, raw_tag);
+        return get_next_completion(h);
+}
+
+/* process completion of a non-indexed command */
+static inline u32 process_nonindexed_cmd(ctlr_info_t *h, u32 raw_tag)
+{
+        u32 tag;
+        CommandList_struct *c = NULL;
+        struct hlist_node *tmp;
+        __u32 busaddr_masked, tag_masked;
+
+        tag = cciss_tag_discard_error_bits(raw_tag);
+        hlist_for_each_entry(c, tmp, &h->cmpQ, list) {
+                busaddr_masked = cciss_tag_discard_error_bits(c->busaddr);
+                tag_masked = cciss_tag_discard_error_bits(tag);
+                if (busaddr_masked == tag_masked) {
+                        finish_cmd(h, c, raw_tag);
+                        return get_next_completion(h);
+                }
+        }
+        bad_tag(h, h->nr_cmds + 1, raw_tag);
+        return get_next_completion(h);
+}
+
+static irqreturn_t do_cciss_intx(int irq, void *dev_id)
+{
+        ctlr_info_t *h = dev_id;
         unsigned long flags;
-        __u32 a, a1, a2;
+        u32 raw_tag;
 
         if (interrupt_not_for_us(h))
                 return IRQ_NONE;
@@ -3324,50 +3410,41 @@ static irqreturn_t do_cciss_intr(int irq, void *dev_id)
          */
         spin_lock_irqsave(CCISS_LOCK(h->ctlr), flags);
         while (interrupt_pending(h)) {
-                while ((a = get_next_completion(h)) != FIFO_EMPTY) {
-                        a1 = a;
-                        if ((a & 0x04)) {
-                                a2 = (a >> 3);
-                                if (a2 >= h->nr_cmds) {
-                                        printk(KERN_WARNING
-                                               "cciss: controller cciss%d failed, stopping.\n",
-                                               h->ctlr);
-                                        spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
-                                        fail_all_cmds(h->ctlr);
-                                        return IRQ_HANDLED;
-                                }
+                raw_tag = get_next_completion(h);
+                while (raw_tag != FIFO_EMPTY) {
+                        if (cciss_tag_contains_index(raw_tag))
+                                raw_tag = process_indexed_cmd(h, raw_tag);
+                        else
+                                raw_tag = process_nonindexed_cmd(h, raw_tag);
+                }
+        }
 
-                                c = h->cmd_pool + a2;
-                                a = c->busaddr;
+        spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
+        return IRQ_HANDLED;
+}
 
-                        } else {
-                                struct hlist_node *tmp;
+/* Add a second interrupt handler for MSI/MSI-X mode. In this mode we never
+ * check the interrupt pending register because it is not set.
+ */
+static irqreturn_t do_cciss_msix_intr(int irq, void *dev_id)
+{
+        ctlr_info_t *h = dev_id;
+        unsigned long flags;
+        u32 raw_tag;
 
-                                a &= ~3;
-                                c = NULL;
-                                hlist_for_each_entry(c, tmp, &h->cmpQ, list) {
-                                        if (c->busaddr == a)
-                                                break;
-                                }
-                        }
-                        /*
-                         * If we've found the command, take it off the
-                         * completion Q and free it
-                         */
-                        if (c && c->busaddr == a) {
-                                removeQ(c);
-                                if (c->cmd_type == CMD_RWREQ) {
-                                        complete_command(h, c, 0);
-                                } else if (c->cmd_type == CMD_IOCTL_PEND) {
-                                        complete(c->waiting);
-                                }
-#                               ifdef CONFIG_CISS_SCSI_TAPE
-                                else if (c->cmd_type == CMD_SCSI)
-                                        complete_scsi_command(c, 0, a1);
-#                               endif
-                                continue;
-                        }
-                }
+        if (interrupt_not_for_us(h))
+                return IRQ_NONE;
+        /*
+         * If there are completed commands in the completion queue,
+         * we had better do something about it.
+         */
+        spin_lock_irqsave(CCISS_LOCK(h->ctlr), flags);
+        raw_tag = get_next_completion(h);
+        while (raw_tag != FIFO_EMPTY) {
+                if (cciss_tag_contains_index(raw_tag))
+                        raw_tag = process_indexed_cmd(h, raw_tag);
+                else
+                        raw_tag = process_nonindexed_cmd(h, raw_tag);
         }
 
         spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
@@ -4230,11 +4307,21 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
 
         /* make sure the board interrupts are off */
         hba[i]->access.set_intr_mask(hba[i], CCISS_INTR_OFF);
-        if (request_irq(hba[i]->intr[SIMPLE_MODE_INT], do_cciss_intr,
-                        IRQF_DISABLED | IRQF_SHARED, hba[i]->devname, hba[i])) {
-                printk(KERN_ERR "cciss: Unable to get irq %d for %s\n",
-                       hba[i]->intr[SIMPLE_MODE_INT], hba[i]->devname);
-                goto clean2;
+        if (hba[i]->msi_vector || hba[i]->msix_vector) {
+                if (request_irq(hba[i]->intr[SIMPLE_MODE_INT],
+                                do_cciss_msix_intr,
+                                IRQF_DISABLED, hba[i]->devname, hba[i])) {
+                        printk(KERN_ERR "cciss: Unable to get irq %d for %s\n",
+                               hba[i]->intr[SIMPLE_MODE_INT], hba[i]->devname);
+                        goto clean2;
+                }
+        } else {
+                if (request_irq(hba[i]->intr[SIMPLE_MODE_INT], do_cciss_intx,
+                                IRQF_DISABLED, hba[i]->devname, hba[i])) {
+                        printk(KERN_ERR "cciss: Unable to get irq %d for %s\n",
+                               hba[i]->intr[SIMPLE_MODE_INT], hba[i]->devname);
+                        goto clean2;
+                }
         }
 
         printk(KERN_INFO "%s: <0x%x> at PCI %s IRQ %d%s using DAC\n",
@@ -4534,46 +4621,5 @@ static void __exit cciss_cleanup(void)
         bus_unregister(&cciss_bus_type);
 }
 
-static void fail_all_cmds(unsigned long ctlr)
-{
-        /* If we get here, the board is apparently dead. */
-        ctlr_info_t *h = hba[ctlr];
-        CommandList_struct *c;
-        unsigned long flags;
-
-        printk(KERN_WARNING "cciss%d: controller not responding.\n", h->ctlr);
-        h->alive = 0;           /* the controller apparently died... */
-
-        spin_lock_irqsave(CCISS_LOCK(ctlr), flags);
-
-        pci_disable_device(h->pdev);    /* Make sure it is really dead. */
-
-        /* move everything off the request queue onto the completed queue */
-        while (!hlist_empty(&h->reqQ)) {
-                c = hlist_entry(h->reqQ.first, CommandList_struct, list);
-                removeQ(c);
-                h->Qdepth--;
-                addQ(&h->cmpQ, c);
-        }
-
-        /* Now, fail everything on the completed queue with a HW error */
-        while (!hlist_empty(&h->cmpQ)) {
-                c = hlist_entry(h->cmpQ.first, CommandList_struct, list);
-                removeQ(c);
-                if (c->cmd_type != CMD_MSG_STALE)
-                        c->err_info->CommandStatus = CMD_HARDWARE_ERR;
-                if (c->cmd_type == CMD_RWREQ) {
-                        complete_command(h, c, 0);
-                } else if (c->cmd_type == CMD_IOCTL_PEND)
-                        complete(c->waiting);
-#ifdef CONFIG_CISS_SCSI_TAPE
-                else if (c->cmd_type == CMD_SCSI)
-                        complete_scsi_command(c, 0, 0);
-#endif
-        }
-        spin_unlock_irqrestore(CCISS_LOCK(ctlr), flags);
-        return;
-}
-
 module_init(cciss_init);
 module_exit(cciss_cleanup);