V4L/DVB (5592): DMA: Correctly free resources on error, sync PCI streamed data

I added saa7146_vmalloc_destroy_pgtable() which frees the resources
allocated by saa7146_vmalloc_build_pgtable() and updated the callers in
budget-core.c and av7110.c. I have also been through the updated
functions and updated the error paths to ensure they free all allocated
resources on error.
I also realised that there are other callers to saa7146_pgtable_free()
which did not have any sg DMA mapped so it seems wrong to add the
pci_unmap_sg() into that function. Instead I created
saa7146_vmalloc_destroy_pgtable() to do this.
Also included in this patch are the previous fixes for pci_unmap_sg()
and syncing the PCI streamed data to work with a SWIOTLB and match the
requirements documented in DMA-API.txt.

Signed-off-by: Jon Burgess <jburgess777@googlemail.com>
Signed-off-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

4 files changed, 63 insertions, 39 deletions

diff --git a/drivers/media/common/saa7146_core.c b/drivers/media/common/saa7146_core.c
index 86cbdbcf9d7d..ef3e54cd9407 100644
--- a/drivers/media/common/saa7146_core.c
+++ b/drivers/media/common/saa7146_core.c
@@ -136,28 +136,45 @@ char *saa7146_vmalloc_build_pgtable(struct pci_dev *pci, long length, struct saa
         char *mem = vmalloc_32(length);
         int slen = 0;
 
-        if (NULL == mem) {
-                return NULL;
-        }
+        if (NULL == mem)
+                goto err_null;
 
-        if (!(pt->slist = vmalloc_to_sg(mem, pages))) {
-                vfree(mem);
-                return NULL;
-        }
+        if (!(pt->slist = vmalloc_to_sg(mem, pages)))
+                goto err_free_mem;
 
-        if (saa7146_pgtable_alloc(pci, pt)) {
-                kfree(pt->slist);
-                pt->slist = NULL;
-                vfree(mem);
-                return NULL;
-        }
+        if (saa7146_pgtable_alloc(pci, pt))
+                goto err_free_slist;
 
-        slen = pci_map_sg(pci,pt->slist,pages,PCI_DMA_FROMDEVICE);
-        if (0 != saa7146_pgtable_build_single(pci, pt, pt->slist, slen)) {
-                return NULL;
-        }
+        pt->nents = pages;
+        slen = pci_map_sg(pci,pt->slist,pt->nents,PCI_DMA_FROMDEVICE);
+        if (0 == slen)
+                goto err_free_pgtable;
+
+        if (0 != saa7146_pgtable_build_single(pci, pt, pt->slist, slen))
+                goto err_unmap_sg;
 
         return mem;
+
+err_unmap_sg:
+        pci_unmap_sg(pci, pt->slist, pt->nents, PCI_DMA_FROMDEVICE);
+err_free_pgtable:
+        saa7146_pgtable_free(pci, pt);
+err_free_slist:
+        kfree(pt->slist);
+        pt->slist = NULL;
+err_free_mem:
+        vfree(mem);
+err_null:
+        return NULL;
+}
+
+void saa7146_vfree_destroy_pgtable(struct pci_dev *pci, char *mem, struct saa7146_pgtable *pt)
+{
+        pci_unmap_sg(pci, pt->slist, pt->nents, PCI_DMA_FROMDEVICE);
+        saa7146_pgtable_free(pci, pt);
+        kfree(pt->slist);
+        pt->slist = NULL;
+        vfree(mem);
 }
 
 void saa7146_pgtable_free(struct pci_dev *pci, struct saa7146_pgtable *pt)
@@ -166,8 +183,6 @@ void saa7146_pgtable_free(struct pci_dev *pci, struct saa7146_pgtable *pt)
                 return;
         pci_free_consistent(pci, pt->size, pt->cpu, pt->dma);
         pt->cpu = NULL;
-        kfree(pt->slist);
-        pt->slist = NULL;
 }
 
 int saa7146_pgtable_alloc(struct pci_dev *pci, struct saa7146_pgtable *pt)
@@ -528,6 +543,7 @@ EXPORT_SYMBOL_GPL(saa7146_pgtable_alloc);
 EXPORT_SYMBOL_GPL(saa7146_pgtable_free);
 EXPORT_SYMBOL_GPL(saa7146_pgtable_build_single);
 EXPORT_SYMBOL_GPL(saa7146_vmalloc_build_pgtable);
+EXPORT_SYMBOL_GPL(saa7146_vfree_destroy_pgtable);
 EXPORT_SYMBOL_GPL(saa7146_wait_for_debi_done);
 
 EXPORT_SYMBOL_GPL(saa7146_setgpio);
diff --git a/drivers/media/dvb/ttpci/av7110.c b/drivers/media/dvb/ttpci/av7110.c
index 67becdd4db60..ef1108c0bf11 100644
--- a/drivers/media/dvb/ttpci/av7110.c
+++ b/drivers/media/dvb/ttpci/av7110.c
@@ -1246,6 +1246,9 @@ static void vpeirq(unsigned long data)
         if (!budget->feeding1 || (newdma == olddma))
                 return;
 
+        /* Ensure streamed PCI data is synced to CPU */
+        pci_dma_sync_sg_for_cpu(budget->dev->pci, budget->pt.slist, budget->pt.nents, PCI_DMA_FROMDEVICE);
+
 #if 0
         /* track rps1 activity */
         printk("vpeirq: %02x Event Counter 1 0x%04x\n",
@@ -2679,8 +2682,8 @@ err_iobuf_vfree_6:
 err_pci_free_5:
         pci_free_consistent(pdev, 8192, av7110->debi_virt, av7110->debi_bus);
 err_saa71466_vfree_4:
-        if (!av7110->grabbing)
-                saa7146_pgtable_free(pdev, &av7110->pt);
+        if (av7110->grabbing)
+                saa7146_vfree_destroy_pgtable(pdev, av7110->grabbing, &av7110->pt);
 err_i2c_del_3:
         i2c_del_adapter(&av7110->i2c_adap);
 err_dvb_unregister_adapter_2:
@@ -2710,7 +2713,7 @@ static int __devexit av7110_detach(struct saa7146_dev* saa)
                 SAA7146_ISR_CLEAR(saa, MASK_10);
                 msleep(50);
                 tasklet_kill(&av7110->vpe_tasklet);
-                saa7146_pgtable_free(saa->pci, &av7110->pt);
+                saa7146_vfree_destroy_pgtable(saa->pci, av7110->grabbing, &av7110->pt);
         }
         av7110_exit_v4l(av7110);
 
diff --git a/drivers/media/dvb/ttpci/budget-core.c b/drivers/media/dvb/ttpci/budget-core.c
index 6b97dc1e6b65..2557ac9620d0 100644
--- a/drivers/media/dvb/ttpci/budget-core.c
+++ b/drivers/media/dvb/ttpci/budget-core.c
@@ -195,6 +195,9 @@ static void vpeirq(unsigned long data)
         u32 newdma = saa7146_read(budget->dev, PCI_VDP3);
         u32 count;
 
+        /* Ensure streamed PCI data is synced to CPU */
+        pci_dma_sync_sg_for_cpu(budget->dev->pci, budget->pt.slist, budget->pt.nents, PCI_DMA_FROMDEVICE);
+
         /* nearest lower position divisible by 188 */
         newdma -= newdma % 188;
 
@@ -504,16 +507,16 @@ int ttpci_budget_init(struct budget *budget, struct saa7146_dev *dev,
         strcpy(budget->i2c_adap.name, budget->card->name);
 
         if (i2c_add_adapter(&budget->i2c_adap) < 0) {
-                dvb_unregister_adapter(&budget->dvb_adapter);
-                return -ENOMEM;
+                ret = -ENOMEM;
+                goto err_dvb_unregister;
         }
 
         ttpci_eeprom_parse_mac(&budget->i2c_adap, budget->dvb_adapter.proposed_mac);
 
-        if (NULL ==
-            (budget->grabbing = saa7146_vmalloc_build_pgtable(dev->pci, budget->buffer_size, &budget->pt))) {
+        budget->grabbing = saa7146_vmalloc_build_pgtable(dev->pci, budget->buffer_size, &budget->pt);
+        if (NULL == budget->grabbing) {
                 ret = -ENOMEM;
-                goto err;
+                goto err_del_i2c;
         }
 
         saa7146_write(dev, PCI_BT_V1, 0x001c0000);
@@ -526,14 +529,16 @@ int ttpci_budget_init(struct budget *budget, struct saa7146_dev *dev,
         if (bi->type != BUDGET_FS_ACTIVY)
                 saa7146_setgpio(dev, 2, SAA7146_GPIO_OUTHI);
 
-        if (budget_register(budget) == 0) {
-                return 0;
-        }
-err:
-        i2c_del_adapter(&budget->i2c_adap);
+        if (budget_register(budget) == 0)
+                return 0; /* Everything OK */
+
+        /* An error occurred, cleanup resources */
+        saa7146_vfree_destroy_pgtable(dev->pci, budget->grabbing, &budget->pt);
 
-        vfree(budget->grabbing);
+err_del_i2c:
+        i2c_del_adapter(&budget->i2c_adap);
 
+err_dvb_unregister:
         dvb_unregister_adapter(&budget->dvb_adapter);
 
         return ret;
@@ -555,15 +560,13 @@ int ttpci_budget_deinit(struct budget *budget)
 
         budget_unregister(budget);
 
-        i2c_del_adapter(&budget->i2c_adap);
-
-        dvb_unregister_adapter(&budget->dvb_adapter);
-
         tasklet_kill(&budget->vpe_tasklet);
 
-        saa7146_pgtable_free(dev->pci, &budget->pt);
+        saa7146_vfree_destroy_pgtable(dev->pci, budget->grabbing, &budget->pt);
 
-        vfree(budget->grabbing);
+        i2c_del_adapter(&budget->i2c_adap);
+
+        dvb_unregister_adapter(&budget->dvb_adapter);
 
         return 0;
 }
diff --git a/include/media/saa7146.h b/include/media/saa7146.h
index 796bcf151a3a..d3f4f5a38214 100644
--- a/include/media/saa7146.h
+++ b/include/media/saa7146.h
@@ -58,6 +58,7 @@ struct saa7146_pgtable {
         unsigned long   offset;
         /* used for custom pagetables (used for example by budget dvb cards) */
         struct scatterlist *slist;
+        int             nents;
 };
 
 struct saa7146_pci_extension_data {
@@ -157,6 +158,7 @@ int saa7146_pgtable_alloc(struct pci_dev *pci, struct saa7146_pgtable *pt);
 void saa7146_pgtable_free(struct pci_dev *pci, struct saa7146_pgtable *pt);
 int saa7146_pgtable_build_single(struct pci_dev *pci, struct saa7146_pgtable *pt, struct scatterlist *list, int length );
 char *saa7146_vmalloc_build_pgtable(struct pci_dev *pci, long length, struct saa7146_pgtable *pt);
+void saa7146_vfree_destroy_pgtable(struct pci_dev *pci, char *mem, struct saa7146_pgtable *pt);
 void saa7146_setgpio(struct saa7146_dev *dev, int port, u32 data);
 int saa7146_wait_for_debi_done(struct saa7146_dev *dev, int nobusyloop);