[IA64] fix SBA IOMMU to handle allocation failure properly

It's possible that SBA IOMMU might fail to find I/O space under heavy
I/Os.  SBA IOMMU panics on allocation failure but it shouldn't; drivers
can handle the failure.  The majority of other IOMMU drivers don't panic
on allocation failure.

This patch fixes SBA IOMMU path to handle allocation failure properly.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 29 insertions, 9 deletions

diff --git a/arch/ia64/hp/common/sba_iommu.c b/arch/ia64/hp/common/sba_iommu.c
index f332e3fe4237..e14c492a8a93 100644
--- a/arch/ia64/hp/common/sba_iommu.c
+++ b/arch/ia64/hp/common/sba_iommu.c
@@ -677,12 +677,19 @@ sba_alloc_range(struct ioc *ioc, struct device *dev, size_t size)
                         spin_unlock_irqrestore(&ioc->saved_lock, flags);
 
                         pide = sba_search_bitmap(ioc, dev, pages_needed, 0);
-                        if (unlikely(pide >= (ioc->res_size << 3)))
-                                panic(__FILE__ ": I/O MMU @ %p is out of mapping resources\n",
-                                      ioc->ioc_hpa);
+                        if (unlikely(pide >= (ioc->res_size << 3))) {
+                                printk(KERN_WARNING "%s: I/O MMU @ %p is"
+                                       "out of mapping resources, %u %u %lx\n",
+                                       __func__, ioc->ioc_hpa, ioc->res_size,
+                                       pages_needed, dma_get_seg_boundary(dev));
+                                return -1;
+                        }
 #else
-                        panic(__FILE__ ": I/O MMU @ %p is out of mapping resources\n",
-                              ioc->ioc_hpa);
+                        printk(KERN_WARNING "%s: I/O MMU @ %p is"
+                               "out of mapping resources, %u %u %lx\n",
+                               __func__, ioc->ioc_hpa, ioc->res_size,
+                               pages_needed, dma_get_seg_boundary(dev));
+                        return -1;
 #endif
                 }
         }
@@ -965,6 +972,8 @@ static dma_addr_t sba_map_page(struct device *dev, struct page *page,
 #endif
 
         pide = sba_alloc_range(ioc, dev, size);
+        if (pide < 0)
+                return 0;
 
         iovp = (dma_addr_t) pide << iovp_shift;
 
@@ -1320,6 +1329,7 @@ sba_coalesce_chunks(struct ioc *ioc, struct device *dev,
         unsigned long dma_offset, dma_len; /* start/len of DMA stream */
         int n_mappings = 0;
         unsigned int max_seg_size = dma_get_max_seg_size(dev);
+        int idx;
 
         while (nents > 0) {
                 unsigned long vaddr = (unsigned long) sba_sg_address(startsg);
@@ -1418,16 +1428,22 @@ sba_coalesce_chunks(struct ioc *ioc, struct device *dev,
                 vcontig_sg->dma_length = vcontig_len;
                 dma_len = (dma_len + dma_offset + ~iovp_mask) & iovp_mask;
                 ASSERT(dma_len <= DMA_CHUNK_SIZE);
-                dma_sg->dma_address = (dma_addr_t) (PIDE_FLAG
-                        | (sba_alloc_range(ioc, dev, dma_len) << iovp_shift)
-                        | dma_offset);
+                idx = sba_alloc_range(ioc, dev, dma_len);
+                if (idx < 0) {
+                        dma_sg->dma_length = 0;
+                        return -1;
+                }
+                dma_sg->dma_address = (dma_addr_t)(PIDE_FLAG | (idx << iovp_shift)
+                                                   | dma_offset);
                 n_mappings++;
         }
 
         return n_mappings;
 }
 
-
+static void sba_unmap_sg_attrs(struct device *dev, struct scatterlist *sglist,
+                               int nents, enum dma_data_direction dir,
+                               struct dma_attrs *attrs);
 /**
  * sba_map_sg - map Scatter/Gather list
  * @dev: instance of PCI owned by the driver that's asking.
@@ -1493,6 +1509,10 @@ static int sba_map_sg_attrs(struct device *dev, struct scatterlist *sglist,
         ** Access to the virtual address is what forces a two pass algorithm.
         */
         coalesced = sba_coalesce_chunks(ioc, dev, sglist, nents);
+        if (coalesced < 0) {
+                sba_unmap_sg_attrs(dev, sglist, nents, dir, attrs);
+                return 0;
+        }
 
         /*
         ** Program the I/O Pdir