rsxx: Handling failed pci_map_page on PowerPC and double free.

The rsxx driver was not checking the correct value during a
pci_map_page failure. Fixing this also uncovered a
double free if the bio was returned before it was
broken up into indiviadual 4k dmas, that is also
fixed here.

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

3 files changed, 37 insertions, 22 deletions

diff --git a/drivers/block/rsxx/core.c b/drivers/block/rsxx/core.c
index 6e85e21445eb..e740a650d546 100644
--- a/drivers/block/rsxx/core.c
+++ b/drivers/block/rsxx/core.c
@@ -654,7 +654,8 @@ static void rsxx_eeh_failure(struct pci_dev *dev)
         for (i = 0; i < card->n_targets; i++) {
                 spin_lock_bh(&card->ctrl[i].queue_lock);
                 cnt = rsxx_cleanup_dma_queue(&card->ctrl[i],
-                                             &card->ctrl[i].queue);
+                                             &card->ctrl[i].queue,
+                                             COMPLETE_DMA);
                 spin_unlock_bh(&card->ctrl[i].queue_lock);
 
                 cnt += rsxx_dma_cancel(&card->ctrl[i]);
diff --git a/drivers/block/rsxx/dma.c b/drivers/block/rsxx/dma.c
index bed32f16b084..71d1ca2a1444 100644
--- a/drivers/block/rsxx/dma.c
+++ b/drivers/block/rsxx/dma.c
@@ -221,6 +221,19 @@ static void dma_intr_coal_auto_tune(struct rsxx_cardinfo *card)
 }
 
 /*----------------- RSXX DMA Handling -------------------*/
+static void rsxx_free_dma(struct rsxx_dma_ctrl *ctrl, struct rsxx_dma *dma)
+{
+        if (!pci_dma_mapping_error(ctrl->card->dev, dma->dma_addr)) {
+                pci_unmap_page(ctrl->card->dev, dma->dma_addr,
+                               get_dma_size(dma),
+                               dma->cmd == HW_CMD_BLK_WRITE ?
+                                           PCI_DMA_TODEVICE :
+                                           PCI_DMA_FROMDEVICE);
+        }
+
+        kmem_cache_free(rsxx_dma_pool, dma);
+}
+
 static void rsxx_complete_dma(struct rsxx_dma_ctrl *ctrl,
                                   struct rsxx_dma *dma,
                                   unsigned int status)
@@ -232,21 +245,14 @@ static void rsxx_complete_dma(struct rsxx_dma_ctrl *ctrl,
         if (status & DMA_CANCELLED)
                 ctrl->stats.dma_cancelled++;
 
-        if (dma->dma_addr)
-                pci_unmap_page(ctrl->card->dev, dma->dma_addr,
-                               get_dma_size(dma),
-                               dma->cmd == HW_CMD_BLK_WRITE ?
-                                           PCI_DMA_TODEVICE :
-                                           PCI_DMA_FROMDEVICE);
-
         if (dma->cb)
                 dma->cb(ctrl->card, dma->cb_data, status ? 1 : 0);
 
-        kmem_cache_free(rsxx_dma_pool, dma);
+        rsxx_free_dma(ctrl, dma);
 }
 
 int rsxx_cleanup_dma_queue(struct rsxx_dma_ctrl *ctrl,
-                           struct list_head *q)
+                           struct list_head *q, unsigned int done)
 {
         struct rsxx_dma *dma;
         struct rsxx_dma *tmp;
@@ -254,7 +260,10 @@ int rsxx_cleanup_dma_queue(struct rsxx_dma_ctrl *ctrl,
 
         list_for_each_entry_safe(dma, tmp, q, list) {
                 list_del(&dma->list);
-                rsxx_complete_dma(ctrl, dma, DMA_CANCELLED);
+                if (done & COMPLETE_DMA)
+                        rsxx_complete_dma(ctrl, dma, DMA_CANCELLED);
+                else
+                        rsxx_free_dma(ctrl, dma);
                 cnt++;
         }
 
@@ -370,7 +379,7 @@ static void dma_engine_stalled(unsigned long data)
 
                 /* Clean up the DMA queue */
                 spin_lock(&ctrl->queue_lock);
-                cnt = rsxx_cleanup_dma_queue(ctrl, &ctrl->queue);
+                cnt = rsxx_cleanup_dma_queue(ctrl, &ctrl->queue, COMPLETE_DMA);
                 spin_unlock(&ctrl->queue_lock);
 
                 cnt += rsxx_dma_cancel(ctrl);
@@ -623,7 +632,7 @@ static int rsxx_queue_dma(struct rsxx_cardinfo *card,
         dma->dma_addr = pci_map_page(card->dev, page, pg_off, dma_len,
                                      dir ? PCI_DMA_TODEVICE :
                                      PCI_DMA_FROMDEVICE);
-        if (!dma->dma_addr) {
+        if (pci_dma_mapping_error(card->dev, dma->dma_addr)) {
                 kmem_cache_free(rsxx_dma_pool, dma);
                 return -ENOMEM;
         }
@@ -736,11 +745,9 @@ int rsxx_dma_queue_bio(struct rsxx_cardinfo *card,
         return 0;
 
 bvec_err:
-        for (i = 0; i < card->n_targets; i++) {
-                spin_lock_bh(&card->ctrl[i].queue_lock);
-                rsxx_cleanup_dma_queue(&card->ctrl[i], &dma_list[i]);
-                spin_unlock_bh(&card->ctrl[i].queue_lock);
-        }
+        for (i = 0; i < card->n_targets; i++)
+                rsxx_cleanup_dma_queue(&card->ctrl[i], &dma_list[i],
+                                        FREE_DMA);
 
         return st;
 }
@@ -990,7 +997,7 @@ void rsxx_dma_destroy(struct rsxx_cardinfo *card)
 
                 /* Clean up the DMA queue */
                 spin_lock_bh(&ctrl->queue_lock);
-                rsxx_cleanup_dma_queue(ctrl, &ctrl->queue);
+                rsxx_cleanup_dma_queue(ctrl, &ctrl->queue, COMPLETE_DMA);
                 spin_unlock_bh(&ctrl->queue_lock);
 
                 rsxx_dma_cancel(ctrl);
@@ -1045,7 +1052,7 @@ int rsxx_eeh_save_issued_dmas(struct rsxx_cardinfo *card)
                 card->ctrl[i].e_cnt = 0;
 
                 list_for_each_entry(dma, &card->ctrl[i].queue, list) {
-                        if (dma->dma_addr)
+                        if (!pci_dma_mapping_error(card->dev, dma->dma_addr))
                                 pci_unmap_page(card->dev, dma->dma_addr,
                                                get_dma_size(dma),
                                                dma->cmd == HW_CMD_BLK_WRITE ?
@@ -1073,7 +1080,7 @@ int rsxx_eeh_remap_dmas(struct rsxx_cardinfo *card)
                                         dma->cmd == HW_CMD_BLK_WRITE ?
                                         PCI_DMA_TODEVICE :
                                         PCI_DMA_FROMDEVICE);
-                        if (!dma->dma_addr) {
+                        if (pci_dma_mapping_error(card->dev, dma->dma_addr)) {
                                 spin_unlock_bh(&card->ctrl[i].queue_lock);
                                 kmem_cache_free(rsxx_dma_pool, dma);
                                 return -ENOMEM;
diff --git a/drivers/block/rsxx/rsxx_priv.h b/drivers/block/rsxx/rsxx_priv.h
index 5ad5055a4104..82779058e8ec 100644
--- a/drivers/block/rsxx/rsxx_priv.h
+++ b/drivers/block/rsxx/rsxx_priv.h
@@ -345,6 +345,11 @@ enum rsxx_creg_stat {
         CREG_STAT_TAG_MASK      = 0x0000ff00,
 };
 
+enum rsxx_dma_finish {
+        FREE_DMA        = 0x0,
+        COMPLETE_DMA    = 0x1,
+};
+
 static inline unsigned int CREG_DATA(int N)
 {
         return CREG_DATA0 + (N << 2);
@@ -379,7 +384,9 @@ typedef void (*rsxx_dma_cb)(struct rsxx_cardinfo *card,
 int rsxx_dma_setup(struct rsxx_cardinfo *card);
 void rsxx_dma_destroy(struct rsxx_cardinfo *card);
 int rsxx_dma_init(void);
-int rsxx_cleanup_dma_queue(struct rsxx_dma_ctrl *ctrl, struct list_head *q);
+int rsxx_cleanup_dma_queue(struct rsxx_dma_ctrl *ctrl,
+                                struct list_head *q,
+                                unsigned int done);
 int rsxx_dma_cancel(struct rsxx_dma_ctrl *ctrl);
 void rsxx_dma_cleanup(void);
 void rsxx_dma_queue_reset(struct rsxx_cardinfo *card);