From 610a63498f7f366031a6327eaaa9963ffa110b2b Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Thu, 8 Jul 2010 10:16:17 +0200 Subject: [PATCH] scsi: fix discard page leak We leak a page allocated for discard on some error conditions (e.g. scsi_prep_state_check returns BLKPREP_DEFER in scsi_setup_blk_pc_cmnd). We unprep on requests that weren't prepped in the error path of scsi_init_io. It makes the error path to clean up scsi commands messy. Let's strictly apply the rule that we can't unprep on a request that wasn't prepped. Calling just scsi_put_command() in the error path of scsi_init_io() is enough. We don't set REQ_DONTPREP yet. scsi_setup_discard_cmnd can safely free a page on the error case with the above rule. Signed-off-by: FUJITA Tomonori Signed-off-by: Jens Axboe --- drivers/scsi/scsi_lib.c | 7 ++----- drivers/scsi/sd.c | 10 ++++++++-- 2 files changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index ee836193f531..b8de389636f8 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1011,11 +1011,8 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) err_exit: scsi_release_buffers(cmd); - if (error == BLKPREP_KILL) - scsi_put_command(cmd); - else /* BLKPREP_DEFER */ - scsi_unprep_request(cmd->request); - + scsi_put_command(cmd); + cmd->request->special = NULL; return error; } EXPORT_SYMBOL(scsi_init_io); diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 0994ab63b598..1d0c4b7c3b69 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -468,6 +468,10 @@ static int scsi_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq) blk_add_request_payload(rq, page, len); ret = scsi_setup_blk_pc_cmnd(sdp, rq); rq->buffer = page_address(page); + if (ret != BLKPREP_OK) { + __free_page(page); + rq->buffer = NULL; + } return ret; } @@ -485,8 +489,10 @@ static int scsi_setup_flush_cmnd(struct scsi_device *sdp, struct request *rq) static void sd_unprep_fn(struct request_queue *q, struct request *rq) { - if (rq->cmd_flags & REQ_DISCARD) - __free_page(virt_to_page(rq->buffer)); + if (rq->cmd_flags & REQ_DISCARD) { + free_page((unsigned long)rq->buffer); + rq->buffer = NULL; + } } /** -- 2.30.2