4 files changed, 77 insertions, 18 deletions

diff --git a/include/sound/memalloc.h b/include/sound/memalloc.h
index 96d0dc171459..d787a6b4a101 100644
--- a/include/sound/memalloc.h
+++ b/include/sound/memalloc.h
@@ -97,7 +97,9 @@ static inline unsigned int snd_sgbuf_aligned_pages(size_t size)
  */
 static inline dma_addr_t snd_sgbuf_get_addr(struct snd_sg_buf *sgbuf, size_t offset)
 {
-        return sgbuf->table[offset >> PAGE_SHIFT].addr + offset % PAGE_SIZE;
+        dma_addr_t addr = sgbuf->table[offset >> PAGE_SHIFT].addr;
+        addr &= PAGE_MASK;
+        return addr + offset % PAGE_SIZE;
 }
 
 /*
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index 8db89630c821..40c5a6fa6bcd 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -996,7 +996,8 @@ snd_pcm_sgbuf_get_ptr(struct snd_pcm_substream *substream, unsigned int ofs)
 
 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream,
                                     unsigned long offset);
-
+unsigned int snd_pcm_sgbuf_get_chunk_size(struct snd_pcm_substream *substream,
+                                          unsigned int ofs, unsigned int size);
 
 /* handle mmap counter - PCM mmap callback should handle this counter properly */
 static inline void snd_pcm_mmap_data_open(struct vm_area_struct *area)
diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index 859b1185e69a..a6d42808828c 100644
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -324,6 +324,32 @@ struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigne
 
 EXPORT_SYMBOL(snd_pcm_sgbuf_ops_page);
 
+/*
+ * compute the max chunk size with continuous pages on sg-buffer
+ */
+unsigned int snd_pcm_sgbuf_get_chunk_size(struct snd_pcm_substream *substream,
+                                          unsigned int ofs, unsigned int size)
+{
+        struct snd_sg_buf *sg = snd_pcm_substream_sgbuf(substream);
+        unsigned int start, end, pg;
+
+        start = ofs >> PAGE_SHIFT;
+        end = (ofs + size - 1) >> PAGE_SHIFT;
+        /* check page continuity */
+        pg = sg->table[start].addr >> PAGE_SHIFT;
+        for (;;) {
+                start++;
+                if (start > end)
+                        break;
+                pg++;
+                if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
+                        return (start << PAGE_SHIFT) - ofs;
+        }
+        /* ok, all on continuous pages */
+        return size;
+}
+EXPORT_SYMBOL(snd_pcm_sgbuf_get_chunk_size);
+
 /**
  * snd_pcm_lib_malloc_pages - allocate the DMA buffer
  * @substream: the substream to allocate the DMA buffer to
diff --git a/sound/core/sgbuf.c b/sound/core/sgbuf.c
index cefd228cd2aa..d4564edd61d7 100644
--- a/sound/core/sgbuf.c
+++ b/sound/core/sgbuf.c
@@ -41,9 +41,11 @@ int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
         tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
         tmpb.dev.dev = sgbuf->dev;
         for (i = 0; i < sgbuf->pages; i++) {
+                if (!(sgbuf->table[i].addr & ~PAGE_MASK))
+                        continue; /* continuous pages */
                 tmpb.area = sgbuf->table[i].buf;
-                tmpb.addr = sgbuf->table[i].addr;
-                tmpb.bytes = PAGE_SIZE;
+                tmpb.addr = sgbuf->table[i].addr & PAGE_MASK;
+                tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT;
                 snd_dma_free_pages(&tmpb);
         }
         if (dmab->area)
@@ -58,13 +60,17 @@ int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
         return 0;
 }
 
+#define MAX_ALLOC_PAGES         32
+
 void *snd_malloc_sgbuf_pages(struct device *device,
                              size_t size, struct snd_dma_buffer *dmab,
                              size_t *res_size)
 {
         struct snd_sg_buf *sgbuf;
-        unsigned int i, pages;
+        unsigned int i, pages, chunk, maxpages;
         struct snd_dma_buffer tmpb;
+        struct snd_sg_page *table;
+        struct page **pgtable;
 
         dmab->area = NULL;
         dmab->addr = 0;
@@ -74,31 +80,55 @@ void *snd_malloc_sgbuf_pages(struct device *device,
         sgbuf->dev = device;
         pages = snd_sgbuf_aligned_pages(size);
         sgbuf->tblsize = sgbuf_align_table(pages);
-        sgbuf->table = kcalloc(sgbuf->tblsize, sizeof(*sgbuf->table), GFP_KERNEL);
-        if (! sgbuf->table)
+        table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
+        if (!table)
                 goto _failed;
-        sgbuf->page_table = kcalloc(sgbuf->tblsize, sizeof(*sgbuf->page_table), GFP_KERNEL);
-        if (! sgbuf->page_table)
+        sgbuf->table = table;
+        pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
+        if (!pgtable)
                 goto _failed;
+        sgbuf->page_table = pgtable;
 
-        /* allocate each page */
-        for (i = 0; i < pages; i++) {
-                if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, device, PAGE_SIZE, &tmpb) < 0) {
-                        if (res_size == NULL)
+        /* allocate pages */
+        maxpages = MAX_ALLOC_PAGES;
+        while (pages > 0) {
+                chunk = pages;
+                /* don't be too eager to take a huge chunk */
+                if (chunk > maxpages)
+                        chunk = maxpages;
+                chunk <<= PAGE_SHIFT;
+                if (snd_dma_alloc_pages_fallback(SNDRV_DMA_TYPE_DEV, device,
+                                                 chunk, &tmpb) < 0) {
+                        if (!sgbuf->pages)
+                                return NULL;
+                        if (!res_size)
                                 goto _failed;
-                        *res_size = size = sgbuf->pages * PAGE_SIZE;
+                        size = sgbuf->pages * PAGE_SIZE;
                         break;
                 }
-                sgbuf->table[i].buf = tmpb.area;
-                sgbuf->table[i].addr = tmpb.addr;
-                sgbuf->page_table[i] = virt_to_page(tmpb.area);
-                sgbuf->pages++;
+                chunk = tmpb.bytes >> PAGE_SHIFT;
+                for (i = 0; i < chunk; i++) {
+                        table->buf = tmpb.area;
+                        table->addr = tmpb.addr;
+                        if (!i)
+                                table->addr |= chunk; /* mark head */
+                        table++;
+                        *pgtable++ = virt_to_page(tmpb.area);
+                        tmpb.area += PAGE_SIZE;
+                        tmpb.addr += PAGE_SIZE;
+                }
+                sgbuf->pages += chunk;
+                pages -= chunk;
+                if (chunk < maxpages)
+                        maxpages = chunk;
         }
 
         sgbuf->size = size;
         dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
         if (! dmab->area)
                 goto _failed;
+        if (res_size)
+                *res_size = sgbuf->size;
         return dmab->area;
 
  _failed: