[PATCH] 3ware: kmap_atomic() fix

We must disable local IRQs while holding KM_IRQ0 or KM_IRQ1.  Otherwise, an
IRQ handler could use those kmap slots while this code is using them,
resulting in memory corruption.

Thanks to Nick Orlov <bugfixer@list.ru> for reporting.

Cc: <linuxraid@amcc.com>
Cc: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/scsi/3w-xxxx.c b/drivers/scsi/3w-xxxx.c
index 25f678d0780b..e8e41e6eb42a 100644
--- a/drivers/scsi/3w-xxxx.c
+++ b/drivers/scsi/3w-xxxx.c
@@ -1508,10 +1508,12 @@ static void tw_transfer_internal(TW_Device_Extension *tw_dev, int request_id,
         struct scsi_cmnd *cmd = tw_dev->srb[request_id];
         void *buf;
         unsigned int transfer_len;
+        unsigned long flags = 0;
 
         if (cmd->use_sg) {
                 struct scatterlist *sg =
                         (struct scatterlist *)cmd->request_buffer;
+                local_irq_save(flags);
                 buf = kmap_atomic(sg->page, KM_IRQ0) + sg->offset;
                 transfer_len = min(sg->length, len);
         } else {
@@ -1526,6 +1528,7 @@ static void tw_transfer_internal(TW_Device_Extension *tw_dev, int request_id,
 
                 sg = (struct scatterlist *)cmd->request_buffer;
                 kunmap_atomic(buf - sg->offset, KM_IRQ0);
+                local_irq_restore(flags);
         }
 }