s390/qdio: add helpers to manage qdio buffers

Users of qdio buffers employ different strategies to manage these
buffers. The qeth driver uses huge contiguous buffers which leads
to high order allocations with all their downsides.

This patch provides helpers to allocate, free, and reset arrays of
qdio buffers using non contiguous pages.

Reviewed-by: Martin Peschke <mpeschke@linux.vnet.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/include/asm/qdio.h b/arch/s390/include/asm/qdio.h
index d786c634e05206ee47271882a6030fac5d3f29b5..06f3034605a19ceaa5dbd80d150bc1308208871f 100644 (file)
--- a/arch/s390/include/asm/qdio.h
+++ b/arch/s390/include/asm/qdio.h
@@ -415,6 +415,10 @@ struct qdio_brinfo_entry_l2 {
 #define QDIO_FLAG_SYNC_OUTPUT          0x02
 #define QDIO_FLAG_PCI_OUT              0x10
 
+int qdio_alloc_buffers(struct qdio_buffer **buf, unsigned int count);
+void qdio_free_buffers(struct qdio_buffer **buf, unsigned int count);
+void qdio_reset_buffers(struct qdio_buffer **buf, unsigned int count);
+
 extern int qdio_allocate(struct qdio_initialize *);
 extern int qdio_establish(struct qdio_initialize *);
 extern int qdio_activate(struct ccw_device *);

diff --git a/drivers/s390/cio/qdio_setup.c b/drivers/s390/cio/qdio_setup.c
index f5f4a91fab44e71b3c7d8ca5e307c19b2b139912..f76bff68d1de875c525b5f76a215787f156c42e8 100644 (file)
--- a/drivers/s390/cio/qdio_setup.c
+++ b/drivers/s390/cio/qdio_setup.c
@@ -17,6 +17,8 @@
 #include "qdio.h"
 #include "qdio_debug.h"
 
+#define QBUFF_PER_PAGE (PAGE_SIZE / sizeof(struct qdio_buffer))
+
 static struct kmem_cache *qdio_q_cache;
 static struct kmem_cache *qdio_aob_cache;
 
@@ -32,6 +34,57 @@ void qdio_release_aob(struct qaob *aob)
 }
 EXPORT_SYMBOL_GPL(qdio_release_aob);
 
+/**
+ * qdio_free_buffers() - free qdio buffers
+ * @buf: array of pointers to qdio buffers
+ * @count: number of qdio buffers to free
+ */
+void qdio_free_buffers(struct qdio_buffer **buf, unsigned int count)
+{
+       int pos;
+
+       for (pos = 0; pos < count; pos += QBUFF_PER_PAGE)
+               free_page((unsigned long) buf[pos]);
+}
+EXPORT_SYMBOL_GPL(qdio_free_buffers);
+
+/**
+ * qdio_alloc_buffers() - allocate qdio buffers
+ * @buf: array of pointers to qdio buffers
+ * @count: number of qdio buffers to allocate
+ */
+int qdio_alloc_buffers(struct qdio_buffer **buf, unsigned int count)
+{
+       int pos;
+
+       for (pos = 0; pos < count; pos += QBUFF_PER_PAGE) {
+               buf[pos] = (void *) get_zeroed_page(GFP_KERNEL);
+               if (!buf[pos]) {
+                       qdio_free_buffers(buf, count);
+                       return -ENOMEM;
+               }
+       }
+       for (pos = 0; pos < count; pos++)
+               if (pos % QBUFF_PER_PAGE)
+                       buf[pos] = buf[pos - 1] + 1;
+       return 0;
+}
+EXPORT_SYMBOL_GPL(qdio_alloc_buffers);
+
+/**
+ * qdio_reset_buffers() - reset qdio buffers
+ * @buf: array of pointers to qdio buffers
+ * @count: number of qdio buffers that will be zeroed
+ */
+void qdio_reset_buffers(struct qdio_buffer **buf, unsigned int count)
+{
+       int pos;
+
+       for (pos = 0; pos < count; pos++)
+               memset(buf[pos], 0, sizeof(struct qdio_buffer));
+}
+EXPORT_SYMBOL_GPL(qdio_reset_buffers);
+
 /*
  * qebsm is only available under 64bit but the adapter sets the feature
  * flag anyway, so we manually override it.