Staging: zram: Fix kunmapping order

This patch fixes the unmapping order of KM_USER0/1 in
handle_uncompressed_page() and zram_read() so that kmap()/kunmap() calls
are correctly nested.

Reported-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Reviewed-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index c5fdc55..d70ec1a 100644 (file)
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -199,8 +199,8 @@ static void handle_uncompressed_page(struct zram *zram, struct bio_vec *bvec,
        cmem = kmap_atomic(zram->table[index].page, KM_USER1);
 
        memcpy(user_mem + bvec->bv_offset, cmem + offset, bvec->bv_len);
-       kunmap_atomic(user_mem, KM_USER0);
        kunmap_atomic(cmem, KM_USER1);
+       kunmap_atomic(user_mem, KM_USER0);
 
        flush_dcache_page(page);
 }
@@ -267,8 +267,8 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
                kfree(uncmem);
        }
 
-       kunmap_atomic(user_mem, KM_USER0);
        kunmap_atomic(cmem, KM_USER1);
+       kunmap_atomic(user_mem, KM_USER0);
 
        /* Should NEVER happen. Return bio error if it does. */
        if (unlikely(ret != LZO_E_OK)) {