staging: hv: Fixed bounce kmap problem by using correct index

commit 0c47a70a9a8a6d1ec37a53d2f9cb82f8b8ef8aa2 upstream.

Fixed bounce offset kmap problem by using correct index.
The symptom of the problem is that in some NAS appliances this problem
represents Itself by a unresponsive VM under a load with many clients writing
small files.

Signed-off-by:Hank Janssen <hjanssen@microsoft.com>
Signed-off-by:Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index d22e35f598ba43a0925281a7df7403da3e7029c2..062519a09b7d706886d75eeb6f1691f3c0dabda9 100644 (file)
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -526,7 +526,7 @@ static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
 
                /* ASSERT(orig_sgl[i].offset + orig_sgl[i].length <= PAGE_SIZE); */
 
-               if (j == 0)
+               if (bounce_addr == 0)
                        bounce_addr = (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])), KM_IRQ0);
 
                while (srclen) {
@@ -587,7 +587,7 @@ static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
                destlen = orig_sgl[i].length;
                /* ASSERT(orig_sgl[i].offset + orig_sgl[i].length <= PAGE_SIZE); */
 
-               if (j == 0)
+               if (bounce_addr == 0)
                        bounce_addr = (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])), KM_IRQ0);
 
                while (destlen) {