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 d49dc21d4cb4a4117c570e5818dee8b2ec5a19eb..9eaca784d2a47d47937873f9ec3b0729bea0aef7 100644 (file)
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -532,7 +532,7 @@ 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) {
@@ -593,7 +593,7 @@ 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) {