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From: Christoph Hellwig <hch@lst.de>
To: linux-scsi@vger.kernel.org
Subject: [PATCH] scsi: ->queue_rq can't sleep
Date: Wed,  7 Jan 2015 15:20:53 +0100	[thread overview]
Message-ID: <1420640453-3493-1-git-send-email-hch@lst.de> (raw)

The blk-mq ->queue_rq method is always called from process context,
but might have preemption disabled.  This means we still always
have to use GFP_ATOMIC for memory allocations, and thus need to
revert part of commit 3c356bde1 ("scsi: stop passing a gfp_mask
argument down the command setup path").

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
---
 drivers/scsi/scsi_lib.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9ea95dd..6d5c0b8 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -591,7 +591,6 @@ static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq)
 static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq)
 {
 	struct scatterlist *first_chunk = NULL;
-	gfp_t gfp_mask = mq ? GFP_NOIO : GFP_ATOMIC;
 	int ret;
 
 	BUG_ON(!nents);
@@ -606,7 +605,7 @@ static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq)
 	}
 
 	ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
-			       first_chunk, gfp_mask, scsi_sg_alloc);
+			       first_chunk, GFP_ATOMIC, scsi_sg_alloc);
 	if (unlikely(ret))
 		scsi_free_sgtable(sdb, mq);
 	return ret;
-- 
1.9.1


             reply	other threads:[~2015-01-07 14:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-07 14:20 Christoph Hellwig [this message]
2015-01-09 11:51 ` [PATCH] scsi: ->queue_rq can't sleep Christoph Hellwig
2015-01-09 15:48   ` Jens Axboe
2015-01-09 12:41 ` Bart Van Assche

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