[PATCH 3.12 054/142] scsi: storvsc: Fix a bug in copy_from_bounce_buffer()

Jiri Slaby
2015-05-16T08:11:22Z

From: "K. Y. Srinivasan" <kys@microsoft.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 8de580742fee8bc34d116f57a20b22b9a5f08403 upstream.

We may exit this function without properly freeing up the maapings
we may have acquired. Fix the bug.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/scsi/storvsc_drv.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 86b05151fdab..97892f258043 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -739,21 +739,22 @@ static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
if (bounce_sgl[j].length == PAGE_SIZE) {
/* full..move to next entry */
sg_kunmap_atomic(bounce_addr);
+ bounce_addr = 0;
j++;
+ }

- /* if we need to use another bounce buffer */
- if (srclen || i != orig_sgl_count - 1)
- bounce_addr = sg_kmap_atomic(bounce_sgl,j);
+ /* if we need to use another bounce buffer */
+ if (srclen && bounce_addr == 0)
+ bounce_addr = sg_kmap_atomic(bounce_sgl, j);

- } else if (srclen == 0 && i == orig_sgl_count - 1) {
- /* unmap the last bounce that is < PAGE_SIZE */
- sg_kunmap_atomic(bounce_addr);
- }
}

sg_kunmap_atomic(src_addr - orig_sgl[i].offset);
}

+ if (bounce_addr)
+ sg_kunmap_atomic(bounce_addr);
+
local_irq_restore(flags);

return total_copied;
--
2.3.7